Essential Oils - Concept and Extraction

#### **Chapter 1**

## Extractions Methods and Biological Applications of Essential Oils

*Sonu Kumar Mahawer, Himani, Sushila Arya, Ravendra Kumar and Om Prakash*

#### **Abstract**

Plants produce secondary metabolites for defense and based on the biosynthetic pathway, these chemical compounds are broadly divided into three categories namely nitrogen-containing compounds, phenolic compounds, and terpenes. Essential oils and other such compounds are known for their biological activities. The extraction of essential oils is a challenging aspect for researchers in the field of natural products. Hydrodistillation is a time-consuming and very tedious method. Nowadays, accelerated solvent extraction, supercritical fluid extraction, subcritical water extraction, microwave hydrodiffusion are promising alternatives for conventional methods with several advantages. Essential oils have several biological activities in the field of pharmacological, ethnopharmacological, pesticidal, etc.

**Keywords:** essential oils, secondary metabolites, hydrodistillation, biological activities, accelerated solvent extraction

#### **1. Introduction**

Essential oils are the highly concentrated, fragrant oil of plant origin that are obtained by steam distillation, dry distillation, hydrodiffusion, or other suitable mechanical methods without heating. These are also denoted as plant "essences" in aromatherapy literature and the method of extraction is critical to categorizing an aromatic constituent as an essential oil [1]. Chemically, these are the mixture of several terpenes or terpenoids which are the polymers of isoprene units. Essential oils are synthesized in the cytoplasm and are usually present in the form of minute droplets between cells. These are insoluble in water, lipophilic and soluble in organic solvents, volatile and aromatic in nature. Almost all plant parts, such as leaves barks, flowers, rhizomes or roots, peels, seeds buds, are reported as the source of essential oils, and several techniques are also known to obtain the essentials from different plant parts [2].

The plant families encompassing species known for most economically significant essential oils are not limited to one taxonomic group only but these are found in all plant classes—gymnosperms such as Pinaceae and Cupressaceae families; angiosperms such as Magnoliopsida, Liliopsida, and Rosopsida. The most important plant families among dicots are Apiaceae, Compositae, Germiniaceae,

Illiciaceae, Lamiaceae, Lauraceae, Myristicaceae, Myrtaceae, Oleaceae, Rosaceae, Santalaceae, etc. whereas, among monocots Zingiberaceae, Poaceae and Acoraceae are the important families [3].

The variations in chemical properties of essential oils vary with their chemical composition and their stereochemical structures, the chemical composition may vary in respect to types of chemical components and their stereochemical nature with the extraction methods used along with the plant type, age, climatic conditions, growth stage, altitude, etc. [4]. Essential oils are the plant secondary metabolites synthesized in the plant cell via metabolic pathways derived from the primary metabolic pathways the synthesis of these metabolites in the plants is often under stress (abiotic and/or biotic) conditions, primarily intervened by different signaling molecules [5] and have been reported for several biological activities which depend upon the chemical composition and stereochemical nature of constituent compounds in essential oils.

In this chapter, we are focusing on the basic information of essential oils, their extraction methods available, and their biological activities in the pharmacological, antimicrobial, and crop protection in agents in agricultural fields.

#### **2. Essential oils and their chemical constituents**

Essential oils are complex mixtures composed of terpenoids and nonterpenoid volatile hydrocarbons. The basic building unit of essential oils is called an isoprene unit (C5H8; 2-methyl-1,3-butadiene) and these are arranged following the isoprene rule in a head-to-tail fashion. There are some functional groups also attached which contribute to the biological activities of the essential oils. These groups are mainly alcohols, aldehydes, esters, ethers, ketones, and phenols [6]. Among terpenes, there are subclasses as monoterpenes, sesquiterpenes, diterpenes in the essential oils. Mono terpenes are the results of the combination of two isoprene units, similarly, sesquiterpenes have resulted from three and diterpenes are from four isoprene units. Alcohols, ketones, and carboxylic acids are the functional groups found in the oxygenated derivatives of terpenes, which are jointly known as terpenoids. Apart from terpenes, alcohols, ketones, esters are also found in essential oils as a single component or in combination with terpenes. The basic classification of terpenes is given in **Table 1**.


**Table 1.** *Classification of terpenes.*

#### **3. Extraction methods**

Various parts of aromatic plants can be extracted to obtain the essential oils. Choice of extraction method depends upon the characteristics and components needed for the purposes. In some circumstances, improper and unsuitable extraction techniques can destruct and alter the biological activity of chemical compounds present in essential oils, for example, loss of active compounds, staining, off flavor, and in some cases physical changes in essential oils. For effective extraction with high efficiency, low cost and less tedious methods are required to obtain the high-quality essential oils with high production yield. There are numerous methods that are available for the extraction of essential oils from different parts of plants.

These methods can be grouped into two categories; conventional methods and advanced methods.

#### **3.1 Convention extraction methods**

#### *3.1.1 Hydrodistillation*

Hydrodistillation is the oldest and most basic oils extraction method which was discovered by Avicenna. The process of extracting essential plant oils by hydrodistillation begins with the plant materials being immersed directly in water inside the vessel and then boiling the entire combination. The devices consist of a heating source, vessel (Alembic), a condenser to convert vapor into liquid, and a decanter to collect the condensate and to separate essential oils with water [7]. This extraction process is a one-of-a-kind way to extract plant materials, such as wood or flowers, and it is commonly employed for extractions requiring hydrophobic natural plant material with a high boiling point. Because the oils are surrounded by water, this process allows essential oils to be extracted at a controlled temperature without overheating. The extraction principle is based on isotropic distillation. Water or other solvents, as well as oil molecules, are present under atmospheric pressure and during the extraction process (heating). The capacity to isolate plant components below 100°C is the fundamental benefit of this extraction approach [8].

#### *3.1.2 Steam distillation*

Steam distillation is a form of distillation or separation technique for temperaturesensitive compounds that are insoluble in water and may break down at their boiling points, such as oils, resins, and hydrocarbons. The basic principle of steam distillation is that it allows a mixture of compounds to be distilled at a temperature that is significantly lower than the individual constituent's boiling point. These compounds, on the other hand, are volatilized at a temperature close to 100°C under atmospheric pressure in the presence of steam or boiling water, by heating plant materials with steam generated by a steam generator. Heat is the primary determinant of how well plant material structures degrade and rupture, releasing aromatic components or essential oils in vapor form [9]. The steam condenses into water when it cools. The film on the water surface (distillate/hydrosol) is then decanted from the top to separate the essential oil from it. At its most basic level, steam distillation has the advantage of being a reasonably inexpensive process to operate, and the qualities of the oils produced by this approach are well known [10]. Masango designed a novel steam distillation extraction technique to enhance separated essential oil yields while

reducing wastewater production during the extraction process. A packed sheet of plant samples is put above the steam source in this setup. Boiling water is not allowed to combine with the botanical components, and only steam is allowed to travel through the plants. As a result, less steam is required in the process, and the amount of water in the distillate can be lowered [11]. In another study, by adopting the steam distillation extraction procedure, Yildirim et al. reported a component 2,2- diphenyl-1-picryl hydrazyl (DPPH) that was utilized to evaluate the antioxidant activities of essential oils [12]. It was shown to have a higher yield of antioxidant components than hydrodistillation-extracted oils.

#### *3.1.3 Cold expression*

In the cold expression method, oil is expeller-pressed at low temperatures and pressure. This method ensures that the resultant oil is 100% pure and keeps all of the plant characteristics. It is a mechanical extraction method in which heat is lowered and minimized throughout the raw material batching process. This process is mostly used to extract essential oils from plants, flowers, seeds, and citrus oils, such as lemon and tangerine [13]. In this process, scrubbing is used to remove the outer layer of the plants that contain the oil. The entire plant is then crushed to extract the substance from the pulp and the essential oil from the vesicles. By centrifugation, the essential oil rises to the surface of the substance and is separated from it [14]. The oils derived in this manner have a short shelf life. According to reports, oil produced in this manner contains more of the fruit aromatic character than oil made any other way.

#### *3.1.4 Destructive distillation*

Only birch (*Betula lenta* or *Betula alba*) and cade trees (Juniperus oxycedrus) are used to extract using this approach. After enduring a destructive process under tremendous heat, the hardest components of these woods (e.g., barks, boughs, and roots) are subjected to dry distillation through tar. After condensation, decantation, and separation, a characteristic leathery and empyreumatic oil is formed [15].

#### *3.1.5 Hydrodiffusion*

Contrasting to steam distillation, the steam in this technique is fed from the top to the bottom of the alembic. Through a perforated tray, the vapor mixture, including Eos, is directly condensed underneath the plant support. Separating EOs is done in the same way as previous distillation processes. In comparison to steam distillation, this approach can minimize steam usage and distillation time while also providing a higher yield [15].

#### **3.2 Advanced extraction methods**

Considering the concepts of economically sound, eco-friendly, high efficiency, and quality production, the efforts were made with respect to the extraction techniques for essential oils from plants.

#### *3.2.1 Microwave-assisted extraction (MAE)*

A microwave is a contactless heat source that can attain more effective and selective heating. Microwaves can complete the distillation in minutes instead of several hours

#### *Extractions Methods and Biological Applications of Essential Oils DOI: http://dx.doi.org/10.5772/intechopen.102955*

in the conventional distillation method. In this method, plant materials are subjected to a microwave reactor with or without organic solvents or water under different levels of microwave treatments, according to the required protocols [15]. Nowadays, this technique is of high attention among researchers because of its unique heating mechanism (based on friction), cost-effectiveness, high efficacy under normal conditions, higher extraction yield, less extraction times, and high selectivity. Several studies have been reported on the extraction of essential oils using MAE. Recently in 2020, Drinić et al. performed the microwave-assisted hydrodistillation (MAHD) of *Origanum vulgare* L. *spp. hirtum* essential oil and compared with conventional hydrodistillation (HD) using Clevenger-type apparatus [16]. For MAHD, they used an apparatus consisting of a microwave oven connected with a Clevenger-type apparatus. The water to plant ratio was kept similar for both HD and MAHD, 20:1 (w/w). MAHD was accomplished at three different power levels (180, 360, and 600 W) till no more essential oil was obtained. MAHD was found to be a method with several pros over conventional HD. MAHD was found to have less extraction time (24–45 min) as compared to HD

**Figure 1.** *Microwave-assisted extraction setup.*

(136 min), higher yields of essential oil (2.55–7.10%) as compared to HD (5.81%), higher oxygenated compounds percentage (78.89–85.15%) as compared to (76.82), and it was proven to be a more eco-friendly method (in terms of electrical consumption (0.135–0.240 kW h) as compared to HD (1.360 kW h). Several authors have been published regarding the optimization of extraction procedure using MAE techniques, for instance, successive microwave-assisted extraction optimization for essential oil from lemon peels waste [17] and microwave extraction of essential oils from Eucalyptus globulus leaves [18], and many more. A schematic diagram of the microwave-assisted extraction setup is depicted in **Figure 1**.

#### *3.2.2 Ultrasound-assisted extraction*

Similar to MAE, ultrasound-assisted extraction has also been developed to enhance the efficacy along with the reduction in extraction time. The collapse of cavitation bubbles generated through ultrasonication mass transfer and release rate of essential oils get increased by the breakdown of cavitation bubble generated and this cavitation effect is largely depending upon different parameters, such as frequency and intensity of ultrasound, incubation time, temperature in UAE, there are less chances of thermal breakdown, and quality and flavor remain better of essential oils [19, 20].

In a study, ultrasound-assisted hydrodistillation was performed to increase the yield of essential oil from cinnamon bark [21]. They optimized several parameters, and the method developed was compared with conventional hydrodistillation. They found an enhanced yield of essential oils along with a significant reduction in extraction time. Moreover, the scrutiny of electricity utilization and CO2 production demonstrates the eco-friendly and economically soundness of ultrasound-assisted hydrodistillation procedure over conventional hydrodistillation. A schematic diagram of the ultrasound-assisted extraction setup is shown in **Figure 2**.

#### *3.2.3 Supercritical fluid extraction (SFE)*

When temperature and pressure are increased over critical points for a given liquid or gas, a supercritical fluid (SF) occurs. The boundary between liquid and gas vanishes in the supercritical zone, and a homogenous fluid arises. Supercritical fluids have a diffusivity and density that distinguishes them from liquids and gases. In contrast to liquids, the density of SFs varies when pressure and temperature values vary, hence a little rise in pressure can result in a massive increase in fluid density, followed by a change in the SF's solvating power. This phenomenon allows for the extraction of specific components from a multicomponent mixture. As a result, supercritical fluid extraction's key benefit is selectivity. The use of this technique may help in the extraction of natural products which have a chance to be degraded at high temperatures. Along with high extraction yield and less extraction time required, this method also allows to recover the solvent used because of the SF's volatile nature, which makes it an economic and environmentally sound extraction method for essential oils and other natural products [22]. Presently, more than 90% of SFE activities are carried out by using CO2, for a variety of uses. CO2 is abstemiously nonflammable, nonexplosive, nontoxic, accessible at cheap cost and high purity, and readily removed from extracts, in addition to having a relatively low critical temperature (32°C) and pressure (7.4 MPa). CO2 also has low surface tension and viscosity but has a diffusivity that is two or three times that of other fluids [23]. CO2 has a polarity similar to pentane in the supercritical zone, making it appropriate for lipophilic compounds

*Extractions Methods and Biological Applications of Essential Oils DOI: http://dx.doi.org/10.5772/intechopen.102955*

#### **Figure 2.** *Schematic diagram of ultrasound-assisted extraction method of essential oils from plant materials.*

extraction. CO2's fundamental flaw is that it lacks the polarity needed to remove polar compounds [24]. Regarding practical application, in a study, the supercritical CO2 extraction was optimized for the extraction of flower essential oil of the tea (*Camellia sinensis* L.) plants. As per the results showed, the optimum conditions were observed as—pressure of 30 MPa, temperature of 50°C, static time of 10 min, and dynamic time of 90 min for successful extraction of essential oils from the flowers of the tea plant in the sufficient amount [25]. A schematic presentation of the supercritical fluid extraction technique is shown in **Figure 3**.

#### *3.2.4 Subcritical water extraction*

Subcritical water is defined as water with a temperature above boiling point to a critical point (100–374°C) and a pressure high enough to keep the liquid condition. A phase diagram of water is shown in **Figure 4**. At ambient temperature and pressure, the dielectric constant of water remains highest among all the nonmetallic liquids,

**Figure 3.** *Schematic diagram of supercritical fluid extraction.*

which is reduced significantly in the range of organic solvents, such as acetonitrile, methanol, ethanol, and acetone, and water acts as organic solvent at this temperature and pressure conditions and the plant compounds can be extracted efficiently using

*Extractions Methods and Biological Applications of Essential Oils DOI: http://dx.doi.org/10.5772/intechopen.102955*

#### **Figure 5.**

*Simple laboratory setup for SCWE.*

subcritical water (**Figure 5**). The extraction by using subcritical water occurs in the following steps; (1) rapid entry into matrix pores, (2) desorption of solutes from active sites of the matrix, (3) dissolution of solutes in the aqueous fluid, (4) diffusion of solutes through static aqueous fluid in porous materials, (5) diffusion of solutes through the layer of stagnant fluid outside particles and finally, (6) elution of solutes by the flowing of the bulk of aqueous fluid [26]. Currently, SCWE is getting importance in the extraction of essential oils also from different plant parts. For example, SCWE is used to extract essential oils from *Alpinia malaccensis* leaves. The optimum conditions for extraction were found as; the temperature of 156°C, extraction time of 25 minutes. They also reported the interaction of temperature and reaction time parameters using regression analysis. They also conducted kinetics modeling and reported that second-order kinetics was followed by SCWE [27].

#### *3.2.5 Turbo distillation*

The turbo distillation method is similar to conventional water distillation; however, in turbo distillation, the mixture is agitated constantly at a suitable speed using a stainless steel stirrer (**Figure 6**). This approach works well with coarse raw materials and difficult-to-extract substances (spices, woods). When compared to aqueous distillation, turbo distillation reduces distillation durations and energy consumption while also preventing volatile components from degradation. In actuality, it is a type of water distillation-based green extraction [28]. Essential oils can be extracted from difficultto-extract parts from plants and others using the turbo distillation extraction method. In a study conducted by Mnayer et al., the essential oils and flavonoids were extracted simultaneously using turbo extraction-distillation [29].

#### *3.2.6 Simultaneous distillation extraction*

Likens and Nickerson established simultaneous distillation–extraction (SDE) in 1964, and it has been effectively used to extract essential oils, aromatic compounds, and other volatile products from a variety of matrices. Steam distillation, in combination with continuous extraction with solvent of the mixture of solvents, becomes superior as compared to conventional solvent extraction or extraction with a mixture of solvents.

#### **Figure 6.** *Turbo hydrodistillation apparatus.*

This is a single-step isolation-concentration technique which reduces extraction time significantly, along with the reduction in the solvents used because of continuous recycling and there is no need for clean up after this approach as the extracts obtained in this technique are devoid of no-volatile components, such as cuticular waxes and chlorophylls [30, 31]. Ribeiro and his coworkers in 2021 performed SDE for the extraction of essential oils from *Rosmarinus officinalis* L [32]. In this study, they assessed the effect of the solvent nature and the optimum time required for extraction. Pentane solvent was found to be best for the performance of SDE for 1 h extraction time.

#### *3.2.7 Pulsed electric field-assisted extraction (PEFAE)*

Pulsed electric field (PEF) reduces negative impacts of traditional heating approaches and is a capable substitute to other extraction methods, such as boiling and ultrasound-assisted or microwave-assisted extraction. Moderate to the high strength of the electric field is used on. The PEFAE technique uses moderate to high electric field strength (EFS) ranging from 100 to 300 V/cm and 20 to 80 kV/cm in batch mode and continuous mode extraction, simultaneously. In the electroporation or electropermeabilization (mechanism involved in PEFAE) external electric force is used to augment the cell membrane permeability [33]. The material of interest is kept in between the electrodes and a high-strength electric field in terms of voltage which punctures the cell membrane by the formation of hydrophilic pores and the membrane, its physical functionality and the extraction takes place [34]. PEFAE is of two types viz. batch PEFAE and continuous PEFAE. In Batch PEFAE, the simple is

#### *Extractions Methods and Biological Applications of Essential Oils DOI: http://dx.doi.org/10.5772/intechopen.102955*

firstly treated with a little solvent between two electrodes and then treated samples removed from the pretreatment unit and stirred at different intensities with the help of a magnetic stirrer to check the solvent evaporation. Apart from the promising results, this process increases operational time because of the low capacity of the system. Therefore, continuous PEFAE is mostly in use at the place of the batch process. In continuous PEFAE, the mixture of solvents is pumped into the treatment chamber by a peristaltic pump at a constant fluid velocity [35]. This technique is getting popularized for the intensification of essential oil extraction [36]. In a study, the PEF was explored for the intensification of essential oil extraction from *Marrubium vulgare*. In this study, PEF pretreatment was done for the purpose of improvement in the permeabilization of the biological membranes. The results revealed a significant enhancement in the extraction rate of essential oils.

#### **4. Biological applications of essential oils**

#### **4.1 Pharmacological applications**

#### *4.1.1 Anticancer mechanism of essential oils*

In most cancer chemotherapies, highly cytotoxic drugs are used that target proliferating cell populations. The nondiscriminatory nature of these drugs leads to severe side effects in normal cells. Natural essential oils and their constituents play a significant role in cancer prevention and treatment. Various mechanisms are responsible for the chemopreventive properties of essential oils, such as antioxidant, antiproliferative, and antimutagenic, enhancing detoxification and synergistic action of their constituents. There is a direct relationship between the production of reactive oxygen species to the origin of oxidation and inflammation that can lead to cancer. Mitochondrial DNA damage can result from oxidative stress which leads to an increase in the mutation rate within cells and thus promoting oncogenic transformation. Besides this, reactive oxygen species (ROs) specifically activate signaling pathways and promote tumor development through the regulation of cellular proliferation, angiogenesis, and metastasis [37]. EOs components react with ROs and form reactive phenoxy radicals which can then react with further ROs to prevent further [38]. EOs also induces the expression of antioxidant enzymes, such as catalase, superoxide dismutase, glutathione peroxidase, and glutathione, which leads to an increase in intracellular antioxidant activity, subsequently leading to a significant reduction in tumor mass (**Figure 7**). Several studies have shown the anticancer activity of EOs against various cancers, some are summarized in **Table 2**.

#### *4.1.2 Essential oil as an antioxidant agent*

Free radicals and other reactive oxygen species cause oxidation of biomolecules which ultimately leads to molecular alterations, including chronic disorders associated with the aging process, arteriosclerosis and cancer [49], Alzheimer's disease [50], Parkinson's disease, diabetes, and asthma. Essential oils also exhibit remarkable antioxidant activity/free radical scavenging activity which has often been confirmed by physicochemical methods (**Table 3**). The essential oils of some medicinally important plants, such as basil, cinnamon, clove, nutmeg, oregano, and thyme, have proven radical-scavenging and antioxidant properties [63]. The antioxidant properties are

mainly dependent on the chemical constituents, such as in *Thymus* the antioxidant activity is mainly attributed to the presence of thymol and carvacrol content (36.5 and 29.8%).

#### **Figure 7.**

*Antioxidant mechanism responsible for chemo preventive mechanism.*


#### **Table 2.**

*Anticancer activity of EOs against various cancer cell lines.*


*Extractions Methods and Biological Applications of Essential Oils DOI: http://dx.doi.org/10.5772/intechopen.102955*


#### **Table 3.**

*Reported antioxidant activities of essential oils of different plant families.*

#### *4.1.3 Essential oil as an antidiabetic agent*

Hyperglycemia is a condition of diabetes that arises as a result of the inability to either produce insulin or use it to regulate normal glucose levels in the blood. Inhibition of α-glucosidase and α-amylase is an important factor to control postprandial hyperglycemia in the management of type 2 diabetes mellitus as both enzymes are involved in the digestion of carbohydrates. α-amylase is involved in the break down of long-chain carbohydrates into disaccharides while α-glucosidase breaks down starch and disaccharides to glucose or monosaccharides. Thus, by inhibiting the enzyme, carbohydrate breakdown can be delayed, and ultimately absorption of glucose in the bloodstream is reduced [64]. Essential oils bind to the active site of the enzyme (α-amylase or α-glucosidase) and act as an inhibitor to form an enzymeinhibitor complex thus inhibiting the enzyme activities (**Figure 8**).

Several essential oils and their constituents have been analyzed for their antidiabetic potential such as essential of plant *Syzygium aromaticum, Cuminum cyminum* [66], *Nepeta hindostana* [57], *Oliveria decumbens*, *Thymus kotschyanus*, *Trachyspermum ammi*, *Zataria* multiflora [67], and *Carthamus tinctorius* [68].

#### **4.2 Antimicrobial application**

EOs and their constituents play a vital role in possessing antimicrobial activities. The antimicrobial activity of essential oil mainly depends on three characteristics the nature of EO (hydrophilic or hydrophobic), its chemical constituents, and the targeted organism [69, 70]. Due to their hydrophobic nature, EOs passes across the cell wall and cytoplasmic membrane and disrupt the cell wall structure and make them more permeable. The membrane permeability leads to leakage of macromolecules and

**Figure 8.**

*Mechanism of enzyme (α-amylase and α-glucosidase) inhibition by essential oil [65].*

*Extractions Methods and Biological Applications of Essential Oils DOI: http://dx.doi.org/10.5772/intechopen.102955*

**Figure 9.** *Mechanism of essential oil action on micro-organisms.*

other cellular materials leading to cell death [71]. In bacteria, the permeabilization of the membranes is associated with loss of ions and reduction of membrane potential, the collapse of the proton pump, and depletion of the ATP pool. EOs can also damage lipids and proteins by coagulating the cytoplasm. **Figure 9** represents different kinds of the mechanism of action of essential oils on microorganisms. The antimicrobial activity of EO's is mostly due to the presence of phenols, aldehydes, and alcohols. Terpenoids are one of the major constituents present in EOs and have oxygen atoms or methyl groups, which are localized or removed from specific enzymes by which they show greater activities. Generally, it has been observed that EOs are more active in gram-positive bacteria than gram-negative bacteria due to the presence of peptidoglycan layer which lies outside the outer membrane. Whereas, in gram-negative bacteria, the outer membrane is composed of a double layer of phospholipids and it is linked with the inner membrane by lipopolysaccharides thus hydrophobic macromolecules, such as essential oils constituents are unable to penetrate the membrane which is responsible for the resistance of the gram-negative bacteria to EOs. Aflatoxins, which are toxic secondary metabolites produced by common fungi, such as *Aspergillus flavus* and *A. parasiticus,* cause contamination of many food products. These aflatoxins are teratogenic, carcinogenic, and mutagenic. Some essential oils not only inhibit the growth of such fungi but can also stop the production of aflatoxins. EOs are effective against a wide range of plants and human pathogenic bacteria, fungi, and viruses by using different assays, as summarized in **Table 4**.


#### **Table 4.**

*Antimicrobial activities of essential oils.*

#### **4.3 Pesticidal applications of essential oils**

Pesticides include a wide range of compounds with very different actions (such as herbicides, insecticides, nematicides, rodenticides, avicides, algicides, fungicides, bactericides, and others) [82]. Due to the high toxicity, environmental pollution, high cost, and many more disadvantages of chemical pesticides, researches are intended toward finding novel solutions with lower toxicity, fewer damaging behavior toward the environment, and a better specificity of action. In this regard, a number of botanicals have historically been used for the control of storage pests, particularly in the Mediterranean region and Southern Asia; however, the importance of essential oils arose in the 1990s following the discovery of their fumigant and contact insecticidal activities against a wide range of pests [83].

Essential oil plays a significant role in the plant's defense against bacteria, viruses, insects, fungi, and herbs. Essential oils are a complex and distinctive mixture of compounds that can be considered for next-generation pesticides. In the case of insecticidal actions, some oils appear to interact with the neuromodulator octopamine, while others appear to interfere with GABA-gated chloride channels, indicating that they have a neurotoxic mechanism of action. With the evidence of the potential of essential oils in pest control, these are considered as new approaches in pest control *Extractions Methods and Biological Applications of Essential Oils DOI: http://dx.doi.org/10.5772/intechopen.102955*


#### **Table 5.**

*Pesticidal applications of essential oils from different plant species.*

**Figure 10.** *Various biological activities of essential oils.* viz. essential oil-based pesticides [84]. There are several applications of essential oils in plant protection, such as insecticidal, herbicidal, nematicidal, and fungicidal. Some such recent studies have been enlisted in **Table 5**.

#### **4.4 Other biological activities of EOs**

Several pharmaceutical and biological activities, such as antibacterial, antifungal, anticancer, antiviral, antidiabetic, antimutagenic, antiprotozoal, anti-inflammatory, antipyretic, analgesic, hepatoprotective, antidiarrheal, antihyperlipidemic, diuretic, neuroprotective, and pesticidal activities, have been reported in various medicinal and aromatic plants bearing essential oil (**Figure 10**) [75]. Essential oils of different plant families of angiospermic plants possess various therapeutic qualities like medicinal and antimicrobial properties (constipation, dysentery, malaria, measles, stomach pain, yellow fever, and dental care).

#### **5. Conclusion**

Essential oils are the important secondary metabolites of plants and are found in almost all parts of the plants. There are several extraction techniques are available. Conventional methods, such as hydrodistillation, steam distillation, cold expression, have several disadvantages. To overcome such cons, researchers have been developed several advanced extraction techniques for essential oils viz. microwave-assisted extraction, supercritical fluid extraction, ultrasound-assisted extraction, subcritical water extraction, etc. These advanced methods also have some cons and there is a need to research for the cheap, easy, eco-friendly methods to be developed. In this chapter, various biological applications, such as pharmacological, antimicrobial, pesticidal activities, have been discussed. There are several aromatic plant species that are remained unexploited for their essential oils and their potential in biological application. There is a need to explore newer species of aromatic plants in this regard and further research is needed in the future in respect to the extraction techniques and biological application of essential oils.

#### **Author details**

Sonu Kumar Mahawer, Himani, Sushila Arya, Ravendra Kumar\* and Om Prakash Department of Chemistry, College of Basic Sciences and Humanities, G.B. Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, India

\*Address all correspondence to: ravichemistry.kumar@gmail.com

© 2022 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

#### **References**

[1] Manion CR, Widder RM. Essentials of essential oils. American Journal of Health-System Pharmacy. 2017;**74**(9): 153-162

[2] Tongnuanchan P, Benjakul S. Essential oils: Extraction, bioactivities, and their uses for food preservation. Journal of food science. 2014;**79**(7):1231-1249

[3] Franz C, Novak J. Sources of essential oils. In: Handbook of Essential Oils. Vol. 10. London: CRC Press; 2020. pp. 41-83

[4] Angioni A, Barra A, Coroneo V, Dessi S, Cabras P. Chemical composition, seasonal variability, and antifungal activity of Lavandula stoechas L. ssp. stoechas essential oils from stem/leaves and flowers. Journal of agricultural and food chemistry. 2006;**54**(12):4364-4370

[5] Hussein RA, El-Anssary AA. Plants secondary metabolites: The key drivers of the pharmacological actions of medicinal plants. Herbal Medicine. 2019;**1**:13

[6] Buckle J. Basic plant taxonomy, basic essential oil chemistry, extraction, biosynthesis, and analysis. Clinical Aromatherapy. 2015. pp. 37-72

[7] Asbahani A, Miladi K, Badri W, Sala M, Addi EHA, Casabianca H, et al. Essential oils: From extraction to encapsulation. International Journal of Pharmaceutics;**483**:220-243

[8] Golmakani MT, Rezaei K. Comparison of microwave-assisted hydrodistillation with the traditional hydrodistillation method in the extraction of essential oils from Thymus vulgaris L. Food Chemistry. 2008;**109**:925-930

[9] Babu KGD, Kaul VK. Variation in essential oil composition of rose scented geranium (Pelargonium sp.) distilled by different distillation techniques. Flavour and Fragrance Journal. 2005;**20**:222-231

[10] Karl-Georg F, Franz-Josef H, Johannes P, Wilhelm P, Dietmar S, Kurt B, et al. Flavors and fragrances. Ullmann's Encyclopedia of Industrial Chemistry. 2003. DOI: 10.1002/ 14356007.a11\_141

[11] Masango P. Cleaner production of essential oils by steam distillation. Journal of Cleaner Production. 2005;**13**:833-839

[12] Yildirim A, Cakir A, Mavi A, Yalcin M, Fauler G, Taskesenligil Y. The variation of antioxidant activities and chemical composition of essential oils of Teucriumorientale L. var. orientale during harvesting stages. Flavour and Fragrance Journal. 2004;**19**:367-372

[13] Arnould-Taylor WE. Aromatherapy for the Whole Person. UK: Stanley Thornes; 1981. pp. 22-26

[14] Rassem HH, Nour AH, Yunus RM. Techniques for extraction of essential oils from plants: A review. Australian Journal of Basic and Applied Sciences. 2016;**10**(16):117-127

[15] Li Y, Fabiano-Tixier AS, Chemat F. Essential oils: From conventional to green extraction. Essential oils as reagents in Green Chemistry. 2014. pp. 9-20

[16] Drinić Z, Pljevljakušić D, Živković J, Bigović D, Šavikin K. Microwave-assisted extraction of O. vulgare L. spp. hirtum essential oil: Comparison with conventional hydro-distillation. Food and Bioproducts Processing. 2020;**120**:158-165

[17] Martínez-Abad A, Ramos M, Hamzaoui M, Kohnen S, Jiménez A, Garrigós MC. Optimisation of sequential microwave-assisted extraction of essential oil and pigment from lemon peels waste. Food. 2020;**9**(10):1493

[18] Tran TH, Ngo TC, Dao TP, Nguyen PT, Pham TN, Nguyen TD, et al. Optimizatoin of Microwaveassisted extraction and compositional determination of essential oil from leaves of Eucalyptus globulus. IOP Conference Series: Materials Science and Engineering. 2020;**736**(2):022040

[19] Asfaw N, Licence P, Novitskii AA, Poliakoff M. Green chemistry in Ethiopia: The cleaner extraction of essential oils from Artemisia afra: A comparison of clean technology with conventional methodology. Green Chemistry. 2005;**7**(5):352-356

[20] Da Porto C, Decorti D, Kikic I. Flavour compounds of *Lavandula angustifolia* L. to use in food manufacturing: Comparison of three different extraction methods. Food Chemistry. 2009;**112**(4):1072-1078

[21] Chen G, Sun F, Wang S, Wang W, Dong J, Gao F. Enhanced extraction of essential oil from Cinnamomum cassia bark by ultrasound assisted hydrodistillation. Chinese Journal of Chemical Engineering. 2021;**36**:38-46

[22] Yousefi M, Rahimi-Nasrabadi M, Pourmortazavi SM, Wysokowski M, Jesionowski T, Ehrlich H, et al. Supercritical fluid extraction of essential oils. TrAC Trends in Analytical Chemistry. 2019;**118**:182-193

[23] Yamini Y, Khajeh M, Ghasemi E, Mirza M, Javidnia K. Comparison of essential oil compositions of *Salvia mirzayanii* obtained by supercritical carbon dioxide extraction and

hydrodistillation methods. Food Chemistry. 2008;**108**(1):341-346

[24] Wang SM, Ling YC, Giang YS. Forensic applications of supercritical fluid extraction and chromatography. Journal of Forensic Sciences. 2003;**2**(5):5-18

[25] Chen Z, Mei X, Jin Y, Kim EH, Yang Z, Tu Y. Optimisation of supercritical carbon dioxide extraction of essential oil of flowers of tea (*Camellia sinensis* L.) plants and its antioxidative activity. Journal of the Science of Food and Agriculture. 2014;**94**(2):316-321

[26] Gbashi S, Adebo OA, Piater L, Madala NE, Njobeh PB. Subcritical water extraction of biological materials. Separation & Purification Reviews. 2017;**46**(1):21-34

[27] Samadi M, Zainal Abidin Z, Yoshida H, Yunus R, Awang Biak DR, Lee CH, et al. Subcritical water extraction of essential oil from *Aquilaria malaccensis* leaves. Separation Science and Technology. 2020;**55**(15):2779-2798

[28] Ghasemy-piranloo F, Kavousi F, Dadashian S. Comparison for the production of essential oil by conventional, novel and biotechnology methods. Authorea Preprints. 2020;**20**:1-34

[29] Mnayer D, Fabiano-Tixier AS, Petitcolas E, Ruiz K, Hamieh T, Chemat F. Simultaneous extraction of essential oils and flavonoids from onions using turbo extraction-distillation. Food Analytical Methods. 2015;**8**(3):586-595

[30] Chaintreau A. Simultaneous distillation–extraction: From birth to maturity. Flavour and Fragrance Journal. 2001;**16**(2):136-148

[31] Teixeira S, Mendes A, Alves A, Santos L. Simultaneous distillation– *Extractions Methods and Biological Applications of Essential Oils DOI: http://dx.doi.org/10.5772/intechopen.102955*

extraction of high-value volatile compounds from Cistus ladanifer L. Analytica Chimica Acta. 2007;**584**: 439-446

[32] Ribeiro BS, Ferreira MD, Moreira JL, Santos L. Simultaneous distillation– Extraction of essential oils from rosmarinus officinalis L. Cosmetics. 2021;**8**(4):117

[33] Panja P. Green extraction methods of food polyphenols from vegetable materials. Current Opinion in Food Science. 2018;**23**:173-182

[34] Redondo D, Venturini ME, Luengo E, Raso J, Arias E. Pulsed electric fields as a green technology for the extraction of bioactive compounds from thinned peach by-products. Innovative Food Science & Emerging Technologies. 2018;**45**:335-343

[35] Ranjha MM, Kanwal R, Shafique B, Arshad RN, Irfan S, Kieliszek M, et al. A critical review on pulsed electric field: A novel technology for the extraction of phytoconstituents. Molecules. 2021;**26**(16):4893

[36] Miloudi K, Hamimed A, Benmimoun Y, Bellebna Y, Taibi A, Tilmatine A. Intensification of essential oil extraction of the Marrubium vulgare using pulsed electric field. Journal of Essential Oil Bearing Plants. 2018;**21**(3):811-824

[37] Storz P. Reactive oxygen species in tumor progression. Frontiers in Bioscience. 2005;**10**(1-3):1881-1896

[38] Arenas DRM, Acevedo AM, Méndez LYV, Kouznetsov VV. Scavenger activity evaluation of the clove bud essential oil (*Eugenia caryophyllus*) and eugenol derivatives employing ABTS+• decolorization. Scientia Pharmaceutica. 2011;**79**(4):779

[39] Rajivgandhi G, Saravanan K, Ramachandran G, Li JL, Yin L, Quero F, et al. Enhanced anti-cancer activity of chitosan loaded *Morinda citrifolia* essential oil against A549 human lung cancer cells. International Journal of Biological Macromolecules. 2020;**164**:4010-4021

[40] Suhail MM, Wu W, Cao A, Mondalek FG, Fung KM, Shih PT, et al. *Boswellia sacra* essential oil induces tumor cell-specific apoptosis and suppresses tumor aggressiveness in cultured human breast cancer cells. BMC Complementary and Alternative Medicine. 2011;**11**(1):1-14

[41] Jayaprakasha GK,

Murthy KC, Uckoo RM, Patil BS. Chemical composition of volatile oil from *Citrus limettioides* and their inhibition of colon cancer cell proliferation. Industrial Crops and Products. 2013;**45**:200-207

[42] Shakeri A, Khakdan F, Soheili V, Sahebkar A, Rassam G, Asili J. Chemical composition, antibacterial activity, and cytotoxicity of essential oil from *Nepeta ucrainica* L. spp. *kopetdaghensis*. Industrial Crops and Products. 2014;**58**:315-321

[43] Wu S, Wei FX, Li HZ, Liu XG, Zhang JH, Liu JX. Chemical composition of essential oil from *Thymus citriodorus* and its toxic effect on liver cancer cells. Journal of Chinese Medicinal Materials. 2013;**36**(5):756-759

[44] Bou DD, Lago JHG, Figueiredo CR, Matsuo AL, Guadagnin RC, Soares MG, et al. Chemical composition and cytotoxicity evaluation of essential oil from leaves of *Casearia sylvestris*, its main compound α-zingiberene and derivatives. Molecules. 2013;**18**(8):9477-9487

[45] Keawsa-Ard S, Liawruangrath B, Liawruangrath S, Teerawutgulrag A, Pyne SG. Chemical constituents and antioxidant and biological

activities of the essential oil from leaves of *Solanum spirale*. Natural Product Communications. 2012;**7**(7):1934578X1200700740

[46] Sigurdsson S, Ogmundsdóttir HM, Gudbjarnason S. The cytotoxic effect of two chemotypes of essential oils from the fruits of *Angelica archangelica* L. Anticancer Research. 2005;**25**(3B):1877-1880

[47] Walia M, Mann TS, Kumar D, Agnihotri VK, Singh B. Chemical composition and in vitro cytotoxic activity of essential oil of leaves of *Malus domestica* growing in Western Himalaya (India). Evidence-Based Complementary and Alternative Medicine. 2012;**2012**:1-6

[48] Li YL, Yeung CM, Chiu LC, Cen YZ, Ooi VE. Chemical composition and antiproliferative activity of essential oil from the leaves of a medicinal herb, *Schefflera heptaphylla*. Phytotherapy Research: An International Journal Devoted to Pharmacological and Toxicological Evaluation of Natural Product Derivatives. 2009;**23**(1):140-142

[49] Gardner P. Superoxide-driven aconitase FE-S center cycling. Bioscience Reports. 1997;**17**:33-42

[50] Butterfield D, Lauderback C. Lipid peroxidation and protein oxidation in Alzheimer's disease brain: Potential causes and consequences involving amyloid beta-peptideassociated free radical oxidative stress. Free Radical Biology & Medicine. 2020;**32**:1050-1060

[51] Kumar R, Kumar R, Prakash O, Srivastava RM, Pant AK. Chemical composition, in vitro antioxidant, antiinflammatory and antifeedant properties in the essential oil of Asian marsh weed *Limnophila indica* L.(Druce). Journal of Pharmacognosy and Phytochemistry. 2019;**8**(1):1689-1694

[52] Dhami A, Singh A, Palariya D, Kumar R, Prakash O, Rawat DS, et al. α-pinene rich bark essential oils of *Zanthoxylum armatum* DC. from three different altitudes of Uttarakhand, India and their antioxidant, in vitro antiinflammatory and antibacterial activity. Journal of Essential Oil Bearing Plants. 2019;**22**(3):660-674

[53] Palariya D, Singh A, Dhami A, Pant AK, Kumar R, Prakash O. Phytochemical analysis and screening of antioxidant, antibacterial and antiinflammatory activity of essential oil of *Premna mucronat*a Roxb. leaves. Trends in Phytochemical Research. 2019;**3**(4):275-286

[54] Goswami S, Kanyal J, Prakash O, Kumar R, Rawat DS, Srivastava RM, et al. Chemical composition, antioxidant, antifungal and antifeedant activity of the *Salvia reflexa* hornem. Essential oil. Asian Journal of Applied Sciences. 2019;**12**(4):185-191

[55] Kanyal J, Prakash O, Kumar R, Rawat DS, Srivastava RM, Singh RP, et al. Study on comparative chemical composition and biological activities in the essential oils from different parts of *Coleus barbatus* (Andrews) Bent. ex G. Don. Journal of Essential Oil Bearing Plants. 2021;**24**(4):808-825

[56] Kumar R, Prakash O, Pant AK, Isidorov VA, Mathela CS. Chemical composition, antioxidant and myorelaxant activity of essential oils of *Globba sessiliflora* Sims. Journal of Essential Oil Research. 2012; **24**(4):385-391

[57] Joshi A, Pant AK, Prakash O, Kumar R, Stocki M, Isidorov VA. Chemical composition, antimicrobial, and antioxidant activities of the essential oils from stem, leaves, and seeds of *Caryopteris foetida* (D. don) Thell.

*Extractions Methods and Biological Applications of Essential Oils DOI: http://dx.doi.org/10.5772/intechopen.102955*

Indian Journal of Natural Products and Resources*.* 2021;**12**(2):214-224

[58] Joshi M, Himani Kumar R, Prakash O, Pant AK, Rawat DS. Chemical composition and biological activities of *Nepeta hindostana* (Roth) Haines, *Nepeta graciliflora* Benth. and *Nepeta cataria* L. from India. Journal of Medicinal Herb*.* 2021;**12**(2):35-46

[59] Thapa P, Prakash O, Rawat A, Kumar R, Srivastava RM, Rawat DS, et al. Essential oil composition, antioxidant, anti-inflammatory, insect antifeedant and sprout suppressant activity in essential oil from aerial parts of *Cotinus coggygria* scop. Journal of Essential Oil Bearing Plants. 2020;**23**(1):65-76

[60] Shahat AA, Ibrahim AY, Hendawy SF, Omer EA, Hammouda FM, Abdel-Rahman FH, et al. Chemical composition, antimicrobial and antioxidant activities of essential oils from organically cultivated fennel cultivars. Molecules. 2011;**16**(2):1366-1377

[61] Han F, Ma GQ, Yang M, Yan L, Xiong W, Shu JC, et al. Chemical composition and antioxidant activities of essential oils from different parts of the oregano. Journal of Zhejiang University-Science B. 2017;**18**(1):79-84

[62] Farouk A, Fikry R, Mohsen M. Chemical composition and antioxidant activity of *Ocimum basilicum* L. essential oil cultivated in Madinah Monawara, Saudi Arabia and its comparison to the Egyptian chemotype. Journal of Essential Oil Bearing Plants. 2016;**19**(5):1119-1128

[63] Tomaino A, Cimino F, Zimbalatti V, Venuti V, Sulfaro V, De PA, et al. Influence of heating on antioxidant activity and the chemical composition of some spice essential oils. Food Chemistry. 2015;**89**:549-554

[64] Butterworth PJ, Warren FJ, Ellis PR. Human α-amylase and starch digestion: An interesting marriage. Starch-Stärke. 2011;**63**(7):395-405

[65] Sani DH, Munna AN, Alam MJ, Salim M, Alam M. Evaluation

of α-amylase inhibition and cytotoxic activities of the *Arachis hypogaea* and *Cinnamomum tamala*. Current Nutrition and Food Science. 2021;**17**(3):328-336

[66] Tahir HU, Sarfraz RA, Ashraf A, Adil S. Chemical composition and antidiabetic activity of essential oils obtained from two spices (*Syzygium aromaticum* and *Cuminum cyminum*). International Journal of Food Properties. 2016;**19**(10):2156-2164

[67] Siahbalaei R, Kavoosi G, Shakeri R. In vitro antioxidant and antidiabetic activity of essential oils encapsulated in gelatin-pectin particles against sugar, lipid and protein oxidation and amylase and glucosidase activity. Food Science & Nutrition. 2020;**8**(12):6457-6466

[68] Li L, Wang Q, Yang Y, Wu G, Xin X, Aisa HA. Chemical components and antidiabetic activity of essential oils obtained by hydrodistillation and three solvent extraction methods from *Carthamus tinctorius* L. Acta Chromatographica. 2012;**24**(4):653-665

[69] Fisher K, Phillips C. Potential antimicrobial uses of essential oils in food: Is citrus the answer? Trends in Food Science and Technology. 2008;**19**(3):156-164

[70] Holley R, Patel D. Improvement in shelf-life and safety of perishable foods by plant essential oils and smoke antimicrobials. Food Microbiology. 2005;**22**(4):273-292

[71] Dorman HD, Deans SG. Antimicrobial agents from plants: Antibacterial activity of plant volatile oils. Journal of Applied Microbiology. 2000;**88**(2):308-316

[72] Chang D, Chen P, Chang S. Antibacterial activity of leaf essential oils and their constituents from *Cinnamomum osmophloeum*. Journal of Ethnopharmacology. 2001;**77**(1):123-127

[73] Karagözlü N, Ergönül B, Özcan D. Determination of antimicrobial effect of mint and basil essential oils on survival of *E. coli* O157:H7 and *S. typhimurium* in fresh-cut lettuce and purslane. Food Control. 2011;**22**(12):1851-1855

[74] Al-Bayati FA. Synergistic antibacterial activity between *Thymus vulgaris* and *Pimpinella anisum* essential oils and methanol extracts. Journal of Ethnopharmacology. 2008;**116**(3):403-406

[75] Raut JS, Karuppayil SM. A status review on the medicinal properties of essential oils. Industrial Crops and Products. 2014;**62**:250-264

[76] Kordali S, Kotan R, Mavi A, Cakir A, Ala A, Yildirim A. Determination of the chemical composition and antioxidant activity of the essential oil of *Artemisia dracunculus* and of the antifungal and antibacterial activities of Turkish *Artemisia absinthium, A. dracunculus, Artemisia santonicum,* and *Artemisia spicigera* essential oils. Journal of Agricultural and Food Chemistry. 2005;**53**(24):9452-9458

[77] Saikia D, Khanuja SP,

Kahol AP, Gupta SC, Kumar S. Comparative antifungal activity of essential oils and constituents from three distinct genotypes of *Cymbopogon* spp. Current Science. 2001;**80**(10):1264-1266

[78] Benkeblia N. Antimicrobial activity of essential oil extracts of various

onions (*Allium cepa*) and garlic (*Allium sativum*). LWT-Food Science and Technology. 2004;**37**(2):263-268

[79] Arena ME, Alberto MR, Cartagena E. Potential use of citrus essential oils against acute respiratory syndrome caused by coronavirus. Journal of Essential Oil Research. 2021;**33**:1-12

[80] Astani A, Reichling J, Schnitzler P. Screening for antiviral activities of isolated compounds from essential oils. Evidence-Based Complementary and Alternative Medicine. 2011;**2011**:1-8

[81] Romeilah RM, Fayed SA, Mahmoud GI. Chemical compositions, antiviral and antioxidant activities of seven essential oils. Journal of Applied Sciences Research. 2010;**6**(1):50-62

[82] Aktar MW, Sengupta D, Chowdhury A. Impact of pesticides use in agriculture: Their benefits and hazards. Interdisciplinary Toxicology. 2021;**2**:1-12

[83] Isman MB. Plant essential oils for pest and disease management. Crop Protection. 2000;**19**(8-10):603-608

[84] Amaral AC, Ramos AS, Pena MR, Ferreira JL, Menezes JM, Vasconcelos GJ. Acaricidal activity of Derris floribunda essential oil and its main constituent. Asian Pacific Journal of Tropical Biomedicine. 2017;**7**:791-796

[85] Rawat A, Thapa P, Prakash O, Kumar R, Pant AK, Srivastava RM, et al. Chemical composition, herbicidal, antifeedant and cytotoxic activity of *Hedychium spicatum* Sm.: A Zingiberaceae herb. TPR. 2019;**3**(2):123-136

[86] Jiang H, Wang J, Song L, Cao X, Yao X, Tang F, et al. Analysis of essential oils composition from leaves, twigs and seeds of *Cinnamomum camphora* L.

*Extractions Methods and Biological Applications of Essential Oils DOI: http://dx.doi.org/10.5772/intechopen.102955*

Presl and their insecticidal and repellent activities. Molecules. 2016;**21**:423

[87] Kumar R, Kumar R, Prakash O. Evaluation of in-vitro herbicidal efficacy of essential oil and chloroform extract of *Limnophila indica*. The Pharma Innovation Journal. 2021;**10**:386-390

[88] Jeon YJ, Lee SG, Lee HS. Acaricidal and insecticidal activities of essential oils of *Cinnamomum zeylanicum* barks cultivated from France and India against Dermatophagoides spp., *Tyrophagus putrescentiae* and *Ricania sp*. Applied Biological Chemistry. 2017;**60**:259-264

[89] Sethi S, Prakash O, Chandra M, Punetha H, Pant AK. Antifungal activity of essential oils of some Ocimum species collected from different locations of Uttarakhand. Indian Journal of Natural Products and Resources. 2013;**4**:392-397

[90] Sethi S, Prakash O, Pant AK. Essential oil composition, antioxidant assay and antifungal activity of essential oil and various extracts of *Alpinia allughas* (Retz.) Roscoe leaves. Cogent Chemistry. 2015;**1**(1):1079349

[91] Sethi S, Prakash O, Pant AK. Phytochemical analysis, antioxidant assay and antifungal activity of essential oil and various extracts of *Alpinia malaccensis* (Burm. f.) Roscoe leaves. Cogent Chemistry. 2016;**2**(1):1223781

#### **Chapter 2**

## Physiochemical Properties of Essential Oils and Applications

*Sunil Kumar Yadav*

#### **Abstract**

Essential oils have received increasing interest due to the high potential of their novel properties, i.e. antibacterial, antifungal and antioxidant activities. Essential oils are obtained from various parts of aromatic cultures, i.e. roots, leaves, seeds, bark, fruits, flowers, stems, etc. by various oil production methods, i.e. field distillation unit (FDU), steam distillation, water and steam distillation & several advanced (supercritical fluid extraction). Therefore, it is necessary to understand the characterization of the essential oils. This study reports on the method of determination of physiochemical properties with the test parameters, i.e. odor, color, optical rotation, solubility, refractive index, specific gravity, acid value, ester value, and ester value after acetylation. There is also discussion about instruments such as gas chromatography-mass spectrometry due to one of the best tools for identifying and quantifying the constituents of essential oils as its simplicity, rapidity, accuracy, and efficiency.

**Keywords:** essential oils, physiochemical properties, method, components, application

#### **1. Introduction**

Essential oils are volatile components of aromatic or aromatic crops that give aroma due to their volatility. Generally, aromatic cultures are those that have aromatic compounds that are volatile at room temperature and give a smell [1]. These compounds are present in essential oils preserved in plant cells, tissues, stomas, and other parts of the plant. Usually, essential oils are stored in the roots, leaves, seeds, bark, fruits, flowers, and stems of plants [2]. The essential oil of the various parts of a plant can be obtained by various distillation methods such as hydro-electric distillation, hydro-vapor distillation, steam distillation, solvent extraction, and supercritical extraction, etc. [3]. Essential oils are the secondary plant metabolites synthesized in different parts of the plant, such as leaves, flowers, stems, roots, and seeds [4]. These are of great importance for perfumery and pharmacy. Natural essential oils are considered biodegradable and have no residual toxicity [5]. Due to the improvement in living standards and taste for natural essential oils as fragrant, flavoring, and pharmaceutical ingredients, the demand for natural essential oils has increased in many ways in the recent past. Many industries use synthetic fragrances that are developed in a laboratory to mimic the aromatic and chemical components of natural oils, based on plants that are more expensive to produce. However, synthetic fragrances may not contain the beneficial aspects of natural plant-based essential oils and may even be dangerous for human applications. Chemicals found in artificial fragrances include, for example, phthalates, endocrine disruptors, and carcinogens known as benzene derivatives [6].

On the other hand, the global market for natural fragrances has grown strongly due to the increasing use of natural fragrances such as essential oils over synthetic fragrances as a result of their associated numerous health benefits associated with them, such as aromatherapy, which will drive market growth in the coming years [7]. The analysis of the essential oil purity test can be confirmed with physiochemical, instrumental analysis. The qualitative and quantitative analysis is carried out to know the components of the oil and the percentage of the components contained in the oil respectively, in doing so, we can know the purity of this particular oil. Only pure oils contain a full range of compounds that simply cannot duplicate cheap imitations.

#### **2. Physico-chemical analysis**

#### **2.1 Odor evaluation**

Take smelling strips and one end of each odors strip must be clearly marked before use. Now, dip the unmarked end of a strip (about 0.5 to 1.0 ml) in the material under examination and of another strip to the same depth in the standard sample after it has attained room temperature. For certain perfumery materials, such as fatty, absolute, and solid aldehydes, solutions of I to 10 percent solutions in ethyl alcohol or diethyl phthalate for olfactory evaluation [8]. Odorant profile of essential oil can be investigated by gas chromatography (GC)-olfactometry using aroma extract dilution analysis (AEDA) and vocabulary-intensity-duration of elementary odors by sniffing (VIDEO-Sniff) [9]. **Table 1** shows the standards for the odor of some essential oils, according to the Bureau of Indian Standards (BIS).

#### **2.2 Solubility determination**

Take exactly 1.0 ml of the essential oil in the measuring cylinder (**Figure 1**) and place it in a constant temperature device [10]. Then, maintain the specified temperature as mentioned in the specification. Now, add the dilute alcohol (as specified) for the particular materials. i.e. 60%, 70%, 80% 90% while shaking. Record the volume of the alcohol required for producing a clear solution. Standards of solubility results for some essential oils are shown in **Table 1**.

#### **2.3 Optical rotation determination**

#### *2.3.1 Polarimeter*

Switch on the light source and wait until full luminosity is obtained (**Figure 2a**) [11]. Then put the blank cell (**Figure 2b**) for normal sample use (100 mm cell) in the cell compartment to get the cell error whether dextro or levo. Now fill up the cell with sample. After that rotate the analyzer knob for alignment with polarized light.


#### *Physiochemical Properties of Essential Oils and Applications DOI: http://dx.doi.org/10.5772/intechopen.104112*



*Physiochemical Properties of Essential Oils and Applications DOI: http://dx.doi.org/10.5772/intechopen.104112*

> **Table 1.** *Physico-chemical propertiesofessential*

 *oils [1–17].*

#### *2.3.2 Digital polarimeter*

Switch on the power input in the instrument (**Figure 3**) then switch on the light source (sodium vapor lamp) knob of the instrument and wait until the energy (70–80 i.e. full intensity of the lamp) is obtained. Now, check the cell error (dextro or levo) then fill the sample in the cell. Put the cell in the cell compartment of the instrument and note the reading, directly from the display of instrument. Optical oration results of some essential oils are shown in **Table 1**.

#### **2.4 Refractive index determination**

Sample should be free from moisture and any other residual matters and record the ambient temperature [12]. Then open the prism of ABBE type refractometer (**Figure 4**) and clean it with soft cotton. Now, place some drops of the oil to be tested on the lower part of the prism and close the refractometer. Then, observe through the eyepiece and turn the dispersion correction compensator knob until the colored indistinct boundary seen between the light and darkfield becomes a sharp line. Now, adjust the knurled knob until the sharp line exactly intersects the midpoint of the cross wires in the image. Read the refractive index from the magnifier in the pointer and record the reading. RI results of some essential oils are shown in **Table 1**.

*Physiochemical Properties of Essential Oils and Applications DOI: http://dx.doi.org/10.5772/intechopen.104112*

**Figure 2.** *(a) Polarimeter and (b) sample cell.*

**Figure 3.** *Digital polarimeter.*

#### **2.5 Specific gravity determination**

The sample should be free from moisture and any other residual matters [13]. Then, carefully wash and clean the pyknometer (**Figure 5**) or specific gravity bottle and dry the interior with a current of dry air. Now, weigh the pyknometer or specific gravity bottle and record the weight and fill the pyknometer or specific gravity bottle with distilled water and record the weight with temperature. Then again clean the pyknometer/specific gravity bottle and dry the interior with a current of dry air.

**Figure 4.** *Abbe type refractometer.*

**Figure 5.** *Pyknometer/specific gravity bottle.*

Now, again fill the same pyknometer/specific gravity bottle with the material under test and record the weight with temperature.

It can be calculated by the equation as under.

$$\mathbf{d} = \frac{W\mathbf{1} - W}{W\mathbf{2} - W} \tag{1}$$

where, d = density, *W* = weight of pycnometer or relative density bottle, *W*1 = weight of sample, *W*2 = weight of distilled water. The relative densities value of some essential oils is shown in **Table 1**.

#### **2.6 Acid value determination**

Sample should be free from moisture and any other residual matters [14]. Weigh about 2.5 g of sample material. Then, dissolve the sample in 20 ml rectified spirit (neutralized). Now, titrate it with potassium hydroxide 0.1 N solution (aqueous/ alcoholic) using phenolphthalein indicator until the solution remains faintly pink after 10 s of shaking. Now, note the volume of KOH consumed and put the value in the formula.

$$\text{Acid value} = \frac{56.1 \times \text{V} \times \text{N}}{\text{M}} \tag{2}$$

where V = volume of KOH consumed, N = normality of KOH solution, M = weight of material (grams) taken.

#### **2.7 Ester value determination**

Take an appropriate sample of the material reserved from the acid value determination [15]. Now, add 25 ml of 0.5 N alcoholic KOH, and reflux it on water bath for 1 h. Then, cool it and add 20 ml distilled water and remove the condenser. Now, add few drops of phenolphthalein as an indicator and titrate it against 0.5 N HCl. Simultaneously, a blank determination is also carried out (conditions remain the same except the material to be tested). Put the values in the following formula.

$$\text{Ester value} = \frac{\mathbf{56.1} \times \mathbf{N} \ (\mathbf{V1} - \mathbf{V2})}{\mathbf{M}} \tag{3}$$

where N = normality of HCl, V1 = vol. in ml of HCl used for blank determination, V2 = vol. in ml. of HCl used in determination to neutralize the excess alkali after hydrolysis, M = weight in g of the material taken.

#### **2.8 Ester value after acetylation determination**

Take 10 ml of sample and 20 ml acetic anhydride and 2 g of anhydrous sodium acetate in a round bottom flask then add fragments of pumice-stone or porcelain pieces [16]. Now, connect the flask with an air condenser for reflux for 2 h. After this, cool the content. Now, add 50 ml of cold water and heat it at a temperature between 40 and 50°C for 15 min. Then again, cool it and transfer it to a separating funnel. After that, wash the flask twice with 10 ml of distilled water and separate the water layer from the oil layer.

Wash the oil layer by shaking successively with (a) 50 ml of sodium chloride solution (brine solution), (b) 50 ml of sodium carbonate (solution 2% in brine), (c) 50 ml of sodium chloride solution (brine), and (d) 20 ml of distilled water. Now, shake the acetylated sample material vigorously with the distilled water and check the water layer with litmus paper as should be neutral. After that, dry the acetylated sample material by adding anhydrous sodium sulfate for the saponification of the ester hydrolysis process. The saponification process is carried out as under steps needed.

First take 1–1.5 g of acetylated sample material into a flask and add 25 ml of 0.5 N alcoholic KOH solution. Then, reflux it in a water bath for one-hour and cool it then

add 20 ml of distilled water from the top of the condenser. Now, titrate it against 0.5 N HCI in the same way, a blank titration is also carried out at the same condition without a sample. Put the value in the following formula for calculation of ester value after acetylation as

$$\text{Ester value after acetylation} = \frac{56.1 \times \text{N} \times (\text{V1} - \text{V2})}{\text{M}} \tag{4}$$

where, N = normality of HCl, *V*<sup>1</sup> = volume in ml of HCl used for blank determination, *V*<sup>2</sup> = volume in ml of HCl used in determination to neutralize the excess alkali after hydrolysis, and M = mass in g of the material taken.

#### **2.9 Instrumental analysis**

#### *2.9.1 GC-MS (gas chromatography-mass spectrometry)*

Gas chromatography-mass spectrometry (GC-MS) analysis is more feasible for the authenticity of essential oil as determining its maximum chemical component. The

#### **Figure 6.**

*(a) Gas chromatography-mass spectrometry instrument, (b) role of the different parts of gas chromatography-mass spectrometry, and (c) gas chromatography-mass spectrometry-chromatogram.*

qualitative GC-MS analysis for the extracted essential oils can be carried out by using HP 6890 gas chromatography coupled with HP 5973 mass selective detector (**Figure 6a**) operating in 70 eV mode. Samples of 0.2 μL need to inject in the capillary column with the split mode at a ratio of 5:1. The compounds separate on a 30 m long capillary column (HP-5MS), 0.25 mm in diameter, and with 0.25 μm thick stationary phase film (5% phenyl)-methylpolysiloxane). The flow rate of helium into the column needs to be kept at 1.2 mL min�<sup>1</sup> . Initially, the temperature of the column 45°C, then it increases to 200°C at a rate of 5°C min�<sup>1</sup> (kept constant for 10 min), and then heat up to a final temperature of 250°C at a rate of 5°C min�<sup>1</sup> (**Figure 6b**).

The oven stays kept at this temperature for 20 min. The solvent delays 4 min. The total running time for a sample is about 70 min. The relative percentage of the essential oil constituents evaluate from the total peak area (TIC) by apparatus software [18]. Essential oil constituents' identification by comparison of their mass spectra (**Figure 6c**) with those stored in the libraries i.e. NIST (National Institute of Standards and Technology), flavor, and Adam's mass spectral libraries using various search engines. **Table 2** is an example of some essential oils and their major components.



**Table 2.**

*Major constituents of the essential oils.*

#### **3. Applications**

The applications of essential oils are diverse. Widely used in cosmetics and perfumes, they also have medicinal applications due to their therapeutic properties as well as agro-alimentary uses because of their antimicrobial and antioxidant effects.

a. Oil of *Mentha arvensis*

Uses for stomach disorders, inflammation, and treatment of fever headache, cold, and asthma.

b. Oil of Geranium

Uses for female reproductive disorders, menstrual cramps, infertility, endometriosis, premenstrual syndrome. Menopausal symptoms, circulatory disorders, Raynaud's disease, varicose veins, hemorrhoids, neuralgia, nervous skin disorders, depression, fatigue, emotional crisis, stress-related conditions, wounds, acne, bruises, minor burns, dermatitis, eczema, ulcers, hemorrhoids, head lice, ringworm, sebum balancing, urinary, and liver tonic.

c. Oil of Vetiver

Uses for nervous tension, muscular spasm, muscular pain, menstrual cramps, premenstrual syndrome, restlessness, acne, arthritis, cuts, depression, exhaustion, insomnia, muscular aches, oily skin, rheumatism, sores, stress.

d. Oil of Citronella (Java)

Uses for muscular aches, infectious skin conditions, fevers, heat rash, excessive perspiration, fungal infections, fatigue, insect bites, insect deterrent.

e. Oil of Eucalyptus globules

Uses for respiratory infection, bronchitis, infectious disease, fever, catarrh, sinusitis, fever, muscular aches and pains, rheumatism, arthritis, urinary infection, cystitis, parasitic infection.

f. Oil of Clove bud

Uses for cognitive support and brain health, pain relief, bacterial infection, fungal infection, viral skin infection, warts, verrucas, toothache, gum disease, muscle pain, rheumatism, flu, bronchitis, tired limbs, nausea, flatulence, stomach cramp, abdominal spasm, parasitic, infection, scabies, ringworm.

g. Oil of Cumin seed

Uses for toxin buildup, poor circulation, low blood pressure, colic, stomach cramps, indigestion, gas, fatigue.

h. Oil of Cardamom

Uses for appetite (loss of), colic, fatigue, stress.

i. Oil of Patchouli

Uses for treating skin conditions such as dermatitis, acne, or dry, cracked skin, easing symptoms of conditions like colds, headaches, and stomach upset, relieving depression, providing feelings of relaxation and helping to ease stress or anxiety, helping with oily hair or dandruff, controlling appetite, using as an insecticide, antifungal, or antibacterial agent, using as an additive in low concentrations to flavor foods like candies, baked goods, and beverages.

j. Oil of Sandalwood

Uses for bronchitis, chapped skin, depression, dry skin, laryngitis, leucorrhea, oily skin, scars, sensitive skin stress, stretch marks.

k. Oil of Ginger

Uses for aching muscles, arthritis, nausea, indigestion, poor circulation, nervous exhaustion.

l. Oil of Palmarosa (var. Motia)

Uses for sinusitis, excess mucus, cystitis, urinary tract infection, gastrointestinal disorders, scarring, wounds acne, pimples, boils, fungal infection, general fatigue, muscular aches, over-exercised muscles, stress, irritability, restlessness, insect bites, and stings.

m. Oil of Lemongrass

Uses for muscular aches and pains, gastrointestinal disorders, indigestion, physical and mental exhaustion acne, insect repellent.

n. Oil of Basil

Uses for bronchitis, colds, coughs, exhaustion, flatulence, flu, gout, insect bites, insect repellent, muscle aches rheumatism, sinusitis.

o. Oil of Cinnamon leaf

Uses for sluggish digestion, colds/flu exhaustion, lice, circulation, rheumatism, scabies, stress.

p. Oil of Dill seed

Uses for dyspepsia, flatulence, indigestion, bronchial asthma, dysmenorrhea, and the promotion of lactation.

q. Oil of Davana

Uses for bacterial infection, bronchial congestion, coughs, colds, influenza, nervous stomach, indigestion, nausea, menstrual cramps, menopausal symptoms, general debility, anxiety, stress, irritability, tension, anxiety, wound healing, antiseptic, coughs.

r. Oil of Himalayan Cedarwood

Uses for acne, arthritis, bronchitis, coughing, cystitis, dandruff, dermatitis, stress.

s. Oil of Black Pepper

Uses for aching muscles, arthritis, chilblains, constipation, muscle cramps, poor circulation, sluggish digestion, quitting smoking, and nicotine addiction.

t. Oil of Jamarosa

Jamarosa essential oil regulates skin moisture & sebum production. Can restore luster to dull aged skin and remove wrinkles & other signs of aging. Has disinfectant, antiseptic properties, and is widely used for treating insect bites and as insect repellents. Aids in repairing the damaged skin cells. Fights anxiety, stress and promotes peaceful sleep.

u. Oil of Rose

Uses for depression, eczema, frigidity, mature skin, menopause, and stress.

#### **4. Conclusion**

This study will facilitate the identification of essential oils or fragrant raw materials purity and quality. Physiochemical methods and their range of value can be utilized by traders of fragrant raw material as avoiding adulteration. GC-MS is an ideal instrumental analysis for maximum major and minor chemical constituents of the essential oils. Advanced analytical techniques for the characterization of essential oils are more reliable by their fruitful results. Since, good quality of the raw material i.e. essential oils can be used in various purposes i.e. antimicrobial, insecticide, antiseptic, antifungal, and analgesic activities, aromatherapy, disease treatments and cosmetics & allied products as desired results. Quality assessment improves the confidence of both producer & consumer as well.

#### **Conflict of interest**

The authors have no conflict of interest to declare.

### **Author details**

Sunil Kumar Yadav Quality Assessment Laboratory, Fragrance and Flavor Development Centre, Ministry of MSME, Government of India, Kannauj, U.P., India

\*Address all correspondence to: sunilffdc@gmail.com

© 2022 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

### **References**

[1] Wissal D, Sana B, Sabrine J, Nada B, Wissem M. Essential oils' chemical characterization and investigation of some biological activities: A critical review. Medicines (Basel). 2016; **3**(4):25. DOI: 10.3390/medicines 3040025

[2] Ghaderinia P, Shapouri R. Assessment of immunogenicity of alginate microparticle containing *Brucella melitensis* 16M oligo polysaccharide tetanus toxoid conjugate in mouse. Banat's Journal of Biotechnology. 2017; **8**(16):83-92

[3] Qing-Wen Z, Li-Gen L, Wen-Cai Y. Techniques for extraction and isolation of natural products: A comprehensive review. Chinese Medicine. 2018;**13**:20

[4] Jones M, Kossel A. A biographical sketch. Yale Journal of Biology and Medicine. 1953;**26**(1):80-97

[5] Falleh H, Jemaa MB, Saada M, Ksouri R. Essential oils: A promising ecofriendly food preservative. Food Chemistry. 2020;**330**:127268. DOI: 10.1016/j.foodchem.2020.127268

[6] Olujimi O, Fatoki OS, Odendaal JP, Okonkwo J. Endocrine disrupting chemicals (phenol and phthalates) in the South African environment: A need for more monitoring. Water SA. 2010;**6**:5. DOI: 10.4314/wsa.v36i5.62001

[7] Jugreet BS, Fawzi MM, Gokhan Z, Filippo M. Essential oils as natural sources of fragrance compounds for cosmetics and cosmeceuticals. Molecules. 2021;**26**(3):666. DOI: 10.3390/molecules26030666

[8] Bureau of Indian Standards (BIS) method for olfactory assessment of natural and synthetic perfumery

materials (First Revision). IS 2284: 1988 (1 Revision): Reaffirmation 2019

[9] Katharina B, Pascal T, Xavier F, Uwe JM, Hugues B, Daniel J, et al. Identification of odor impact compounds of *Tagetes minuta* l. essential oil: Comparison of two GC-olfactometry methods. Journal of Agricultural and Food Chemistry. 2009;**57**(18):8572-8580. DOI: 10.1021/jf9016509

[10] Bureau of Indian Standards (BIS). Determination of solubility. IS 326 (Part 6): 2005 (RA 2015)

[11] Bureau of Indian Standards (BIS). Methods of sampling and test for natural and synthetic perfumery materials: Part 4 determination of optical rotation (Third Revision), IS 326: Part 4: 2005/ ISO 592: 1998 (2 Revision)

[12] Methods of sampling and test for natural and synthetic perfumery materials: Part 5 determination of refractive index (Third Revision): IS 326: Part 5:2006/ISO 280: 1998:(3 Revision)

[13] Bureau of Indian Standards (BIS). Methods of sampling and test for natural and synthetic perfumery materials: Part 3 determination of relative density (Third Revision), IS 326:Part 3:2006/ISO 279:1998 (3 Revision)

[14] Bureau of Indian Standards (BIS). Methods of sampling and test for natural and synthetic perfumery materials: Part 7 determination of acid value (Third Revision): IS 326:Part 7:2006/ISO 1242: 1999 (3 Revision)

[15] Bureau of Indian Standards (BIS). Methods of sampling and test for natural and synthetic perfumery materials part8 determination of ester value (Third

*Physiochemical Properties of Essential Oils and Applications DOI: http://dx.doi.org/10.5772/intechopen.104112*

Revision): IS 326:Part 8:2005/ISO 709: 2001 (2 Revision)

[16] Bureau of Indian Standards (BIS). Methods of sampling and test for natural and synthetic perfumery materials: Part 9: determination of ester value and free alcohols. Section 1: determination of ester values, before and after acetylation, and evaluation of the contents of free and total alcohols (Third Revision): IS 326:Part 9:Sec 1:2017/ISO 1241: 1996

[17] Bureau of Indian Standards (BIS). Manak Bhavan, 9 Bahadur Shah Zafar Marg, New Delhi-110002. Available from: https://standardsbis.bsbedge.com/

[18] Hassanpouraghdam MB, Hassani A, Shalamzari MS. Menthone-and estragole-rich essential oil of cultivated *Ocimum basilicum* L. from Northwest Iran. Chemija. 2010;**21**:59-62

[19] Harpreet K, Ritu T, Anu K, Charu M. Chemical composition and antifungal activity of essential oils from aerial parts of *Mentha piperita* and *Mentha arvensis*. International Journal of Pharmacognosy. 2018;**5**(12):767-773

[20] Farukh SS, Hanjing Z, William NS. Composition of geranium (*Pelargonium graveolens*) essential oil from Tajikistan. American Journal of Essential Oils and Natural Products. 2014;**2**(2):13-16

[21] Smitha GR, Varghese TS, Manivel P. Vol. 387. Anand, Gujarat: Icar— Directorate of Medicinal and Aromatic Plants Research Boriavi; 2014. p. 310

[22] Lee SW, Wendy W. Chemical composition and antimicrobial activity of cymbopogon nardus citronella essential oil against systemic bacteria of aquatic animals. Iranian Journal of Microbiology. 2013;**5**(2):147-152

[23] Ismail A, Ester I, Francis M, William K. Chemical composition of essential oils from Eucalyptus globulus and Eucalyptus maculata grown in Tanzania. Scientific African. 2021;**12**:e00758

[24] Nurdjannah N, Bermawie N. Handbook of Herbs and Spices. Woodhead Publishing Series in Food Science, Technology and Nutrition; 2012. pp. 197-215

[25] Sahadeo DP, Maniker PP, Sushilkumar JW, Chandrakiran SU, Mahendra KR. Chemical composition, antimicrobial and antioxidant activity of essential oils from cumin and ajowan. 2016;**8**(1):60-65

[26] Wei-Cai Z, Zeng Z, Hong G, Li-Rong J, Qiang H. Chemical composition, antioxidant, and antimicrobial activities of essential oil from pine needle (*Cedrus deodara*). Journal of Food Science. 2012; **77**:C824-C829

[27] Kaliyaperumal AK, Sampathrajan V, Muthusamy M, Dhanya MK, Gunasekaran A, Shaji A, et al. Essential oil profile diversity in cardamom accessions from southern India. Frontiers in Sustainable Food Systems. 2021;**5**:1-8

[28] Ermaya D, Sari SP, Patria A, Hidayat F, Razi F. Identification of patchouli oil chemical components as the results on distillation using GC–MS. IOP Conference Series: Earth and Environmental Science. 2019;**365**:1-5

[29] Upul S, Manuri G, Hettiarachchi DS. Essential oil content and composition of Indian sandalwood (*Santalum album*) in Sri Lanka. Journal of Forest Research. 2013;**24**:27-130

[30] Pantea S, Roshanak M, Leila A, Maryam HM. Volatile constituents of ginger oil prepared according to Iranian traditional medicine and conventional method: A comparative study. African Journal of Traditional, Complementary, and Alternative Medicines. 2016;**13**(6): 68-73

[31] Rajeswara Rao BR, Rajput DK, Patel RP. Essential oil profiles of different parts of palmarosa (*Cymbopogon martinii* (roxb.) wats. var. motia burk.). Journal of Essential Oil Research. 2009;**21**:519-521

[32] Somit RC, Tandon PK, Chowdhury AR. Chemical composition of the essential oil of *Cymbopogon flexuosus* (steud) wats. growing in Kumaon region. Journal of Essential Oil-Bearing Plants. 2010;**13**:588-593

[33] Poonkodi K, Subban R. Chemical composition of the essential oil from basil (*Ocimum basilicum* Linn.) and its in vitro cytotoxicity against HeLa and HEp-2 human cancer cell lines and NIH 3T3 mouse embryonic fibroblasts. Natural Product Research. 2012;**26**(12):1112-1118

[34] Erich S, Leopold J, Gerhard B, Gernot AE, Ivanka S, Albert K, et al. Composition and antioxidant activities of the essential oil of cinnamon (*Cinnamomum zeylanicum* blume) leaves from Sri Lanka. Journal of Essential Oil-Bearing Plants. 2006;**9**:170-182

[35] Vishaldeep K, Ramandeep K, Urvashi B. A review on dill essential oil and its chief compounds as natural biocide. 2021;**36**:412-431

[36] Stefanie B, Gerhard B, Erich S, Juergen W, Alexander S, Albena S, et al. GC-MS-analysis, antimicrobial activities and olfactory evaluation of essential davana (*Artemisia pallens* wall. ex dc) oil from India. Natural Product Communications. 2008;**3**(7):1057-1062

[37] Ewa R, Renata NW, Andrzej S, Piotr G. The chemical composition of the essential oil of leaf celery (*Apium graveolens* l. var. *Secalinum alef*.) under the plants' irrigation and harvesting method. Acta Scientiarum Polonorum Hortorum Cultus. 2016;**15**(1):147-157

[38] Mohamed G, Badr S, Maroc AC, Abderrahman A. Turpentine chemical composition and antimicrobial activity of *Pinus pinaster* and *Pinus halepensis* of Morocco. Acta Botanica Gallica. 2007; **154**:29-300

[39] Chaudhary A, Kaur P, Singh B, Pathania V. Chemical composition of hydrodistilled and solvent volatiles extracted from woodchips of Himalayan Cedrus: *Cedrus deodara* (Roxb.) Loud. Natural Product Communications. 2009; **4**(9):1257-1260

[40] Milos N, Dejan S, Jasmina G, Ana C, Tatjana M, Marija S, et al. Could essential oils of green and black pepper be used as food preservatives? Journal of Food Science and Technology. 2015;**52**: 6565-6573

[41] Nadeem A, Saxena BK. Isolation of geraniol content from various essential oils. The Asian Journal of Experimental Chemistry. 2009;4(1&2):14-17

[42] Ram SV, Rajendra CP, Amit C, Anand S, Ajai KY. Volatile constituents of essential oil and rose water of damask rose (*Rosa damascena* mill.) cultivars from North Indian hills. Natural Product Research. 2011;**25**:1577-1584

#### **Chapter 3**

## Essential Oil as Green Preservative Obtained by Ecofriendly Extraction Techniques

*Nashwa Fathy Sayed Morsy*

#### **Abstract**

Essential oils are formed by a complex matrix of substances that are biosynthesized in the secondary metabolism of plants. Nowadays, different ecofriendly extraction techniques (e.g., ultrasound-, microwave-, enzyme-assisted extraction, and supercritical fluid by CO2, etc.) have been adopted to obtain essential oils. These techniques provide unique quality of essentials oils or extracts from aromatic plants in a short time with high energy savings. Essential oils not only impart aroma, but also possess antimicrobial and antioxidant activities. Health limitations in the use of synthetic additives have drawn researchers' attention towards essential oils as safe natural preservatives. Therefore, this chapter summarizes novel technologies to recover essential oils or extracts. In addition, it focuses on application of essential oils and their constituents as green preservatives to retard microbial growth and oxidative spoilage.

**Keywords:** essential oil, green preservative, ecofriendly techniques, enzyme assisted extraction, ultrasound assisted extraction

#### **1. Introduction**

Conventional techniques (hydrodistillation, steam distillation) used for EO extraction from aromatic plants have several disadvantages such as long extraction time, high energy consumption and degradation of thermally labile aromatic compounds [1]. Characteristic natural flavor of an essential oil depends mainly on its components and their concentrations. Therefore, extraction procedure has to be sensitive enough to keep the proportions of its constituents in their natural state. The oxygenated compounds of EO is considered the main indicator for its quality [2]. The level of these compounds in the EO is affected by the extraction technique used. Recently, novel (green) techniques have been applied solely or in combination with other technique to recover essential oils with high quality in a short time [3]. These green techniques include: Enzyme (EAE), ultrasound (UAE), and microwave (MAE) and supercritical fluid extraction (SFE) [4].

Essential oils (EOs) are used in a wide range of food types as biopreservatives according to their antioxidant and antimicrobial properties [5]. Essential oils are

directly added to food matrix, incorporated into food packaging materials, applied in edible coatings or in modified atmosphere packaging [6]. Some EOs and their components such as carvacrol, carvone, cinnamaldehyde, citral, eugenol, linalool, limonene, thymol and vanillin, were accepted for use as flavorings and food additives by the European Commission. Application of essential oils at high concentration required in food preservation is limited by its sensorial characteristics, which would affect negatively the original organoleptic properties of foods [7–9].

#### **2. Ecofriendly extraction techniques**

#### **2.1 Ultrasonic assisted extraction (UAE)**

Ultrasonication is considered as a green extraction technique for EO [10]. Ultrasound (U) waves are successfully utilized in the extraction of essential oils, oleoresins, and other bioactive compounds from spice matrices [11]. The advantages of this technique include: low-temperature, short extraction time, low energy consumption, and superior quality of the extracted EO [12]. Microsecond pulses of ultrasound wave generated vapor bubbles within the liquid medium. The bubbles expanded to a large size during expansion cycles before implosion on the surface of plant material, that lead to micro cracking in the cell wall which helps to penetrate the solvent in the cell wall of the powder and release the intracellular components into the medium [13]. This observation could be noticed in **Figure 1**.

There are two types of UAE of EO: ultrasound (US) as a pretreatment prior to HD and simultaneous ultrasound-assisted HD extraction [14]. The UAE efficiency of EO is affected by power, sonication time, frequency, temperature, solvent type and liquid to solid ratio.

Lilia et al. [15] evaluated the effect of UAE time (10, 20, 30, 45 and 60 min) prior to HD on the EO yield from dried flowering tops of *Lavandula stoechas* L. Plants were collected from two regions: Keddara and Adekar in Algeria. The highest yield was obtained in the Adekar sample (1.59%) and Keddara sample (0.87%) after 10 min and 45 min of ultrasound (US), respectively. UAE pretreatment was followed by HD for 90 min. However, the yield of EO obtained by conventional HD (180 min) represented ~70% of that produced by US-HD technique.

Wu et al. [16] extracted EO from dried aerial parts of *Artemisia annua* by ultrasonic-assisted steam distillation extraction. The investigated independent factors were steam distillation (SD) time (1 h, 3.5, and 6 h), US time (0 h, 0.5, 1 h), and solid to liquid ratio (g/mL) (1:6, 1:10 and 1:14). The EO yield reached 0.71% with the optimal conditions (SD extraction time of 3.5 h, US time of 0.5 h, and solid to liquid ratio of 1:10 (g/mL) instead of 0.49% obtained with the conventional SD for 6 h.

Jadhav et al. [17] investigated the UAE of EO from *Piper betle* leaf powder in presence of water at different sonication time (20, 30 and 40 min), dissipated energy (5.64, 12.24, 19.8, 34.56, and 47.32 W) and temperature (30, 40, 50 and 60°C), with different leaf powder to solvent ratios (1:3, 1:4, 1:5 and 1:6). The maximum yield of EO (0.5%) was recorded at 30 min of US irradiation while it did not exceed 0.35% after 3 h of HD. Increasing temperature more than 30°C, dissipated energy higher than 34.56 W and solvent to solid ratio higher than 5 did not significantly increase the yield of EO. They attributed the obtained results at high US power to the formation of large bubble cloud in the solvent that shielded and scattered the bubble energy discharged during the collapse process.

*Essential Oil as Green Preservative Obtained by Ecofriendly Extraction Techniques DOI: http://dx.doi.org/10.5772/intechopen.103035*

#### **Figure 1.**

*Scanning electron micrographs of wild mint (Mentha longifolia) leaves (a) control without any treatment (b) after extraction with HD for 3 h (c) after extraction with U (60 W) for 10 min (d) after extraction with U (60 W) for 10 min + HD for 33 min (×200–×1000 magnification, 25 kV).*

Chen et al. [14] studied the effect of the US power on EO yield from cinnamon bark. The samples were subjected to US irradiation ranged from 100 to 500 W for 30 min prior HD. The EO yield (2%) increased with the increase of US power to 300 W. The yield decreased at higher US irradiation (>300 W). They attributed this decrement to high temperature generated, high acoustic pressure created, formation of big bubbles and increase of cavitation bubbles bursting that led to decomposition of EO constituents. Extending US time to 30°min caused a significant increase in EO yield and decrease HD time from 2 h to 1 h. Further increase in US time caused lower yield due to loss of volatile constituents. US at water to solid ratios ranged from 4 to 12 (mL/g) was evaluated. The highest EO yield was recorded for water to solid ratio of 6 (mL/g) and decreased with the continual increase of liquid to solid ratio due to the reduction of the ultrasound intensity needed for the breakage of cell walls. Statistical analysis of the data showed that the order of influence of the dependent factors on EO yield was US time > HD time > US power > liquid to solid ratio.

Ghule et al. [18] extracted eugenol and eugenol acetate from ground clove buds by ultrasound assisted hydrotropic extraction (UAHE). Sodium cumene sulfonate was used to prepare the hydrotropic solution, since solubility of eugenol in water was found to be 1.35 g/L instead of 500 g/L in the aqueous solution (1.8 M) of sodium cumene sulfonate. The extraction time (15–75 min), temperature (30–70°C), hydrotrope concentration (0.2–1.8 M), solid loading (6–22 g/150 mL of hydrotrope solution) and US power (120–200 W) were selected as independent variables. The combined yield of eugenol and eugenol acetate was used as a response. After sonication the mixture was filtered. Eugenol and its derivative were recovered from the filtrate by extraction with hexane. The highest extraction yield (20.04%) was obtained with the following optimal conditions; US power of 158 W, 38°C, hydrotrope concentration of 1.04 M, solid loading of 8.2 g, and extraction time of 30 min. The EO yield obtained by conventional hydrotropic extraction for 1 h was not significantly different than that resulted from UAHE technique.

Guo et al. [19] used ultrasound to enhance subcritical water extraction (USWE) of EO from ground cinnamon bark. The following independent factors were used, through Box-Behnken design, to optimize the extraction conditions: extraction time (20, 25, and 30 min), extraction temperature (120, 130, and 140°C), and US power (100, 125, and 150 W) with a pressure of 5 MPa. The yield of cinnamaldehyde was set as the dependent variable, while its content in the EO was used as a quality index. They compared USWE with the following extraction techniques: steam distillation for 4 h, ultrasound assisted extraction (UAE) by dichloromethane with US power of 150 W for 40 min, and subcritical water extraction (SWE) under pressure of 5 MPa, with a liquid to solid ratio of 12 mL/g, at 132°C for 38 min. Although UAE resulted in the highest EO yield (2.1%) compared to other extraction techniques (1.58–1.83%), the cinnamaldehyde content that obtained with UAE was the lowest (8.965 mg/g). The optimal conditions of USWE were found to be extraction time of 25 min, extraction temperature of 140°C, and US power of 145 W, a pressure of 5 MPa and liquid to solid ratio of 8 mL/g. Under these conditions the maximum yield of EO and cinnamaldehyde content were 1.78% and 12.662 mg/g, respectively. Results indicated that coupling ultrasound with SWE shortened the extraction time and improved the quality of the obtained EO.

Zhang et al. [20] extracted EO from dried citronella leaves with ultrasonic ohmic heating distiller in presence of distilled water. The EO yield of 18 mL/kg dry weight as obtained with liquid to solid ratio of 6. Increasing liquid to solid ratio to 12 caused significant decrease in the yield. They attributed this to difficult in distilling out the EO from large volume of solvent. Meanwhile, increasing US power from 36 to 144 W was accompanied by a significant increase in the EO yield. No significant increase in the EO yield was noticed by further increase in US power. Increasing the current intensity from 1 to 5 A significantly increased EO yield to 20 mL/kg dry weight. This yield was obtained when extraction process was conducted for 40 min, after which no further increase was observed. They suggested that excessive extraction time under the US and ohmic conditions used affected negatively the release of EO due to gelatinization of intracellular components. They used response surface method to optimize the extraction conditions. The EO yield reached 22.91 mL/kg dry weight under the optimal conditions (liquid to solid ratio of 7 mL/g, US power of 180 W, current of 5°A, and time of 30 min).

#### **2.2 Enzyme-assisted extraction (EAE)**

The EAE technique is considered as a green extraction technology [21]. In EAE, hydrolytic enzymes act on the polysaccharides of the cell wall, disrupt it and release *Essential Oil as Green Preservative Obtained by Ecofriendly Extraction Techniques DOI: http://dx.doi.org/10.5772/intechopen.103035*

#### **Figure 2.**

*Scanning electron micrographs of lemon verbena (Aloysia citrodora) leaves (a) control without any treatment (b) after HD (c) pretreated with Cellulase (d) pretreated with pectinase (e) pretreated with Viscozyme.*

the intracellular essential oil and other bioactive compounds [22]. This observation could be noticed in **Figure 2**.

However, low solubility of essential oil in the aqueous buffer system restrains complete extraction [23, 24]. Therefore, this technique is used as a pretreatment to enhance extraction of volatile oil. The extraction of essential oils (EOs) is carried out by a single enzyme or a combination of enzymes; i.e. cellulase, hemicellulase, pectinase, protease, amylase or viscozyme (mixture of cellulase, arabinase, β-glucanase, hemicellulase and xylanase) [25]. Mahmoudi et al. [26] found that treating sweet basil (*Ocimum basilicum* L.) leaves with viscozyme before HD increased the EO yield to 9.32% instead of 6.1% in the control samples. Enzymatic pretreatment was carried out with 5 mg of enzyme/50 g leaves in distilled water (250 mL) during stirring at 40°C for 1 h prior to HD for 2 h. Li et al. [27] reported that EAE of EO from *Mentha haplocalyx* leaves with a mixture of enzymes (cellulase and pectinase) was more efficient than each of them. They attributed this effect to the synergistic influence of enzyme mixture on the cell wall. Moreover, the efficiency of EAE is affected by type and activity of enzymes used, enzyme concentration, buffer to solid ratio, incubation temperature, and incubation time [28, 29]. In addition, difference in plant structures affects the enzyme efficiency with respect to the oil yield [30].

Baby and Ranganathan [31, 32] pretreated cardamom and fennel seeds with either of celluclast, pectinex, viscozyme and protease prior to steam distillation led to an increase in EO yield by 7–16% and 11–22.5%, respectively. The maximum yield was obtained by viscozyme at 1% (*v/w*) under optimized conditions of 50°C, pH 5 and incubation time of 90 min. GC-MS analysis showed that enzyme pretreatment increased significantly the main characteristic oxygenated compounds (1,8-cineole and α-terpinyl acetate) in cardamom EO and *trans*-anethole and fenchone in fennel EO.

Increasing enzyme concentration enhances the degradation of cell wall and the release of EO up to a level after which no significant increase of EO yield could be

obtained [32]. They ascribed this to the saturation of enzyme sites by the substrate. Shimotori et al. [33] treated peppermint (*Mentha arvensis*) leaves powder with enzyme aqueous solution at a ratio of 1:10 (*w/v*). Each of cellulase and hemicellulose was used at different concentrations (0.1, 1.0, 2.0, 5.0 and 10.0%, *w/w*), individually. The mixture was incubated for 3 h at 40°C, before subjecting to hydrodistillation for 1 h to obtain EO. Levels of L*-*menthol and L-menthone, the main components of EO, were used to examine the efficiency of the treatment. Maximum yields of L-menthol and L-menthone were obtained at each enzyme concentration of 2%. They found that the yield of EO increased by the combined use of 2% cellulase and 2% hemicellulase compared with the use of one enzyme.

Pretreatment of *Ocimum canum* aerial parts powder with viscozyme at 1% concentration before HD increased the EO yield to 1.2% compared to 0.83% with HD only [34]. This pretreatment decreased HD time from 180 to 30 min. They found that EAE increased the level of oxygenated monoterpenes in the obtained oil.

Vladić et al. [35] incubated *Origanum vulgare* aerial parts with viscozyme at 8%, pH 4.9, 45°C for 60 min before extraction for 4 h increased EO yield to 6.59% compared to 3.39% that obtained by the control. The EAE led to an increase of oxygenated compounds in the extracted EO to 94.67% compared to the control (88.06%).

#### **2.3 Microwave-assisted extraction**

Microwave-assisted extraction (MAE) accelerates the extraction of EO and saves energy and time without negative changes in the EO composition [36]. Microwaves (electromagnetic waves) rotate molecules with dipoles inside the plant cell that creates heat, generates high inwards pressure (as a result of the abrupt rise in temperature) on the cell wall disrupts it and releases cells' content into the extraction medium [37].

Hassanein et al. [38] extracted EO from the dried aerial parts of 7 plants from Lamiaceae family (*Origanum majorana* L., *Mentha pipereta* L., *Mentha longifolia* L., *Origanum syriacum* L., *Lavandula angustifolia* L., *Rosmarinus officinalis* L., and *Thymus vulgaris* L.) using MAHD at 100°C and 800 W for 60 min. The yield and oxygenated constituents of EO extracted by MAHD were higher than those of EO obtained by the HD technique in 180 min, indicating the higher quality of MAHD EOs. They reported that long extraction time by HD enhanced decomposition of the oxygenated compounds.

Ghazanfari et al. [39] extracted EO from coriander seeds powder by microwaveassisted hydrodistillation (MAHD). The microwave oven was operated as follows; 10 min at 800 W up to 100°C, and then kept at 100°C for 60 min at 500 W, followed by 10 min of ventilation. The EO yield (*v/w*) obtained by MAHD (0.325%) was not significantly different (*p* > 0.05) from that extracted by HD (0.31%). The MAHD technique reduced extraction time from 240 min during HD to 60 min.

Memarzadeh et al. [40] studied the effect of microwave-assisted steam hydrodiffusion (MSHD) technique and extraction time on the EO yield of the Bakhtiari savory (*S. bachtiarica* Bunge.) aerial parts. The MSHD was carried out at 800 W for 75 min. The highest EO yield (1.80, *v/w* dry weight basis) was obtained after 60 min of MSHD *vs* 150 min by the HD. The maximum level of oxygenated monoterpenes (69%) was obtained by MSHD after 20 min instead of 65.5% that extracted by the HD after 150 min. The MSHD technique reduced energy required for EO recovery from 4.5 kWh by the HD to 0.26 kWh.

Yingngam et al. [41] used solvent-free microwave extraction (SFME) attached to a Clevenger apparatus to retrieve EO from the fresh *Shorea roxburghii* flowers. The

#### *Essential Oil as Green Preservative Obtained by Ecofriendly Extraction Techniques DOI: http://dx.doi.org/10.5772/intechopen.103035*

moisture content of the fresh flowers ranged between 69% and 74%. They subjected water inside plant cells to microwave energy. The effects of microwave power (480, 640, and 800 W) and irradiation time (10, 30, and 50 min) as independent variables, on the EO yield (%, *w/w*) were evaluated. The highest yield of EO (0.0114%) was recorded at 780 W and 38 min. The oil obtained by HD for 8 h had the similar yield. The EO recovered by SFME technique was characterized by the same scent of fresh flowers. The energy consumption decreased from 3.60 kWh by HD to 0.58 kWh with the SFME. In other research, Yingngam et al. [42] used the same SFME technique to extract EO from fresh aerial parts of *Limnophila aromatic* (70.11–75.14% moisture content)*.* The highest yield of EO (0.21% *v/w*) was recovered at 700 W and 25 min instead of 4 h by HD. Oxygenated monoterpenes of the EO produced by SFME technique (50.29%) was higher than that obtained by HD (39.09%). However, they reported that the quality of the EO obtained by both methods was similar. Peng et al. [43] used a combined technique of solvent-free MAE (SFME) and the screw extrusion of *Pinus pumila* fresh needles to obtain the EO. Response surface method was applied to optimize the extraction conditions. The investigated independent factors used were; moisture content (30, 40, and 50%), MAE time (20, 30, and 40 min), and MAE power (385, 540, and 700 W) while yield of EO was the response factor. Fresh needles were crushed in the extrusion treatment and the cell wall was ruptured with the increase of intracellular pressure in the cells due to the evaporation of water (100°C) by the microwave irradiation. Increasing the moisture content of needles from 20% to 40%, increased the yield of EO. The highest yield (12.00 mL/kg) was obtained at moisture content of 40%, power of 540 W and irradiation time of 30 min. On the other hand, the EO yield from *P. pumila* did not exceed 7.00 mL/kg after 4 h of conventional HD.

#### **2.4 Supercritical fluid extraction by CO2**

Supercritical fluid extraction (SFE) is a green, non-selective, and solvent free technique [44]. Carbon dioxide is applied in the SFE because it is cheap, non-flammable, has low critical temperature (31.1°C) and pressure (73.8 bar) and has a polarity appropriate for extraction of non-polar materials such as EO [45]. **Figure 3** illustrates a flow diagram of SFE.

This extraction technique, avoid degradation of thermolabile compounds compared to other techniques. However, the SFE has the disadvantage of high investment and operating costs [46].

Quintana et al. [47] reported that SFE produces high yield extracts with higher quality but lower concentration of volatile compounds compared with HD technique.

The efficiency of SFE process is affected by the following independent variables: particle size of the material, pressure, temperature, co-solvent and time [48].

The most appropriate particle size of the ground material is within the range of 0.4–0.8 mm [49]. The decrease of particle size (diameter) increases surface area of the material that is subjected to fluid CO2 and enhances the extractability of the target components. Too small particle size reduces extract yield due to agglomeration of particles and reduction of surface area [50]. Under SFE conditions, increasing pressure at a specific temperature increases the CO2 density, and consequently the solubility of the target compounds. However, increasing pressure above a certain level could result in a higher solubility of waxes and other hydrocarbons besides essential oil components. Meanwhile, increased temperature at constant pressure decrease the CO2 density, and reduce the extraction yield though it increases the vapor pressure of

**Figure 3.** *A flow diagram of supercritical fluid extraction by CO2.*

the EO [51, 52]. The SFE temperature is used in the range 35–50°C to avoid degradation of thermolabile compounds. Since CO2 is nonpolar, addition of small amounts of co-solvents (polar modifiers) such as methanol and ethanol increase the solubility of more polar compounds (phenolic compounds). The moisture content of the plant material can be used as a modifier. However, the modifier has to be separated from the resulted extract [45].

Markom et al. [53] studied the effect of co-solvents on the efficiency of SFE of EO from *Polygonum minus* dried leaves. The co-solvents used were: water, methanol, ethanol, and aqueous solutions of methanol and ethanol. The SFE was performed at 40°C and pressure of 150 bars. The CO2 flow rate was 3 mL/min while the cosolvents flow rate was adjusted at 0.3 mL/min. The static and dynamic periods were set for 20 min and 240 min, respectively. The highest extraction yields (>25%) were obtained by the aqueous solutions of methanol and ethanol while the lowest yields (<9%) were obtained by the pure alcohols. The yield reached ~20% when water was used as a co-solvent.

Ara et al. [54] used central composite design to optimize the extraction yield of EO from *Descurainia sophia* L. ground dried seeds by SFE. The independent factors were: pressure (100, 228 and 355 bar), temperature (35, 50 and 65°C), modifier volume (methanol) (50, 100 and 150 μL), dynamic time (10, 25 and 40 min) and static extraction time (10, 25 and 40 min). The EO yield was used as a response. They found that increasing static extraction time from 10 to 40 min at the same extraction conditions (100 bar, 35°C, dynamic time of 10 min, without modifier) caused a slight increase in the yield from 0.5 to 1.1%. Increasing extraction temperature from 35 to 65°C at the same extraction conditions (100 bar, dynamic time of 40 min, static time of 10 min and modifier, 100 μL) resulted the same extraction yield (1.2%). Therefore, temperature and static time were fixed at 65°C and 10 min, respectively. Increasing pressure from 100 bar to 228 bar, at the same extraction conditions (methanol, 100 μL and dynamic time, 25 min), increased the extraction yield from 2.07 to 10.4%, due to increase of CO2 density, which increases the solubility of the target components. Increasing modifier volume from 50 to 100 and 150 μL, at the same extraction conditions (228 bar and dynamic time, 25 min), increased the extraction yield from 9.24 to 10.4 and 12.72%, respectively. They attributed this increase to the ability of polar modifier to increase the solubility of polar compounds in the CO2 and consequently, increases the extraction yield. The highest yield (18.48%) was obtained at the optimum conditions (355 bar, 65°C, static time of 10 min, dynamic time of 35 min and modifier volume of 150 μL).

Oliveira et al. [55] extracted EO fractions from *Piper divaricatum* dried leaves using SFE at temperature of 35°C and 55°C, and pressure of 100, 300 and 500 bar. Increasing pressure from 100 bar to 300 bar at 35°C caused an increase in the CO2 density from 712.8 to 929.1 kg/m3 , which consequently increased significantly the EO yield from 4.68 to 6.03% dry weight basis. Further increase in pressure to 500 bar, at the same temperature, did not significantly increase the yield, though the CO2 density increased to 1005 kg/m3 . The same trend was also noted when SFE was performed at 55°C using the same investigated levels of pressure. The yields at 55°C were found to be higher than those at 35°C. The highest yield (7.15%) was obtained at 55°C/300 bar instead of 3.03% that obtained after 3 h of HD. The highest concentrations of eugenol (21.7%) and methyl eugenol (61.85%) and the lowest concentration of eugenyl acetate (4.35%) were recorded for the EO obtained by HD. The concentration of eugenol did not exceed 13.2% in the extracts obtained by SFE. The SFE extracts were characterized by higher level of eugenyl acetate (>14.75%).

Marzlan et al. [56] extracted the EO from dried ground Torch ginger inflorescence with SFE at combinations of temperature of 34.7, 38, 46, 54, and 57.3°C and pressure of 83.6, 125, 225, 325 and 366.4 bar. The static and dynamic times were 2 h and 1 h, respectively. At a constant temperature (46°C), increasing pressure from 83.6 bar to 225 bar caused an increase in the EO yield from 0.65 to 5.2%, while continual increase in pressure to 366.4 bar resulted in a decrease in EO yield to 4.16%. On the other hand, at a constant pressure (225 bar), increasing temperature from 34.7 to 46°C caused an increase in the EO yield from 3.68 to 5.21%, while continual increase in temperature to 57.3°C resulted in a low increase in EO yield to 5.72%.

Silva et al. [57] obtained the EO from dried ground leaves of *Lippia thymoides* by SFE at 40 and 50°C, and pressures of 100, 200, and 300 bar. The static and the dynamic periods were 30 min and 120 min, respectively. The EO yield was 1.29% (*w/w*) at 200 bar and increased to ~1.6% (*w/w*) at 300 bar, regardless of the temperature used. The thymol (the major constituent, >74%) and oxygenated monoterpene contents of the EO obtained at 50°C were higher than those extracted at 40°C, regardless the level of pressure used.

#### **3. Essential oil as a green preservative and flavoring agent**

#### **3.1 Essential oil as antioxidant agent**

Oxidation of food products during processing and/or storage causes undesirable changes. It affects negatively nutritional quality and consumer acceptability (color changes and off-flavors). Antioxidants at low concentrations can delay

oxidative reactions and extend the shelf life of the food products [58]. Many essential oils have antioxidant properties through scavenging of free-radicals and singlet oxygen quencher [59–62]. Essential oil constituents like thymol, eugenol, carvacrol, linalool, 1,8-cineole, geranial/neral, citronellal, isomenthone, and menthone are potent antioxidants. They can convert free radicals into more stable compounds by the addition of hydrogen atoms [63]. Strong antioxidant activity of essential oils is attributed to their phenolic structure [64].

The peroxide value (PV) is used for assessing the early stages of fat oxidation. Meanwhile, the thiobarbituric acid (TBA) value represented the secondary product (Malondialdehyde (MDA) of oxidation of polyunsaturated fatty acids. Direct addition of peppermint essential oil to refined soybean oil (without synthetic antioxidant) at 200 ppm or packaging it in a high density polyethylene package incorporated with 3700 ppm peppermint essential oil kept its oxidative stability not significantly different from that containing 200 ppm butylated hydroxyl toluene (BHT) during storage for 45 days at 40°C [65]. They attributed this activity to the main constituents: L-menthol, menthone and isomenthone of essential oil. Mezza et al. [66] found that addition of rosemary essential oil, obtained by hydrodistillation, to refined sunflower oil at 0.1 g/100 g extended its shelf life from 26 days to 36 days during storage in a dark place at 23°C, in presence of air. Meanwhile, the residue fractions of the essential oil, obtained by molecular distillation, displayed a longer shelf life that reached 44 days at the same storage conditions. The levels of less volatile constituents (camphor, α-terpineol and *cis*-sabinene hydrate) increased progressively with successive stages of molecular distillation. Okhli et al. [67] investigated the antioxidant properties of Citron peel essential oil, obtained by steam distillation, on sunflower oil at 800 ppm during storage at 65°C for 5 days. Oxidative stability of oil samples was measured with a Rancimat apparatus. Oxidative stability of oil samples enriched with essential oil (3.39 h) was higher than that of oil supplemented with 200 ppm BHT (3.0 h) at the end of storage period.

Immersion of Atlantic mackerel (*Scomber scombrus*) fillets in 1% (*w/v*) basil (*Ocimum basilicum*) and rosemary (*Rosmarinus officinalis*) essential oils for 30 min at 2°C and stored at the same temperature after packing into air-proofed polyamide/ polyethylene packs delayed the development of lipid oxidation. TBA of the treated samples was followed during storage. TBA value exceeded the acceptable level (~5 mg MDA/kg of fish flesh according to Bensid et al. [68] after 8, 10, and 11 days for the control, rosemary, and basil groups, respectively. The basil and rosemary essential oils extended the shelf life of the fish fillets by 2 and 3 days, respectively, compared to the control group [69].

Boskovic et al. [70] evaluated the efficacy of thyme and oregano essential oils in retarding lipid oxidation of minced pork stored in modified conditions (vacuum and 30% O2 conditions) at 3 ± 1°C during 15 days of storage. Minced pork samples were homogenized with different concentrations (0%, 0.3%, 0.6%, and 0.9%) of thyme or oregano essential oils. The control mince was prepared without essential oils. Essential oils reduced significantly (*p* < 0.05) the TBARS (mg malondialdehyde/kg) values in the mince even at the low level (0.3%). Minced samples with this concentration of essential oil were sensory acceptable. The antioxidant activity was attributed to the phenolic compounds in the investigated volatile oils.

Dipping raspberry fruits into lemon verbena essential oil emulsion at 250 μl/L for 3 min reduced the damage caused by reactive oxygen species during cold storage at 4°C for 9 days and extended shelf life of the fruits. The use of this essential oil as an edible coating increased antioxidant activity measured by inhibition of 2.2 diphenyl picrylhydrazyl (DPPH) radicals from 50.99 to 85.63% [71].

#### *Essential Oil as Green Preservative Obtained by Ecofriendly Extraction Techniques DOI: http://dx.doi.org/10.5772/intechopen.103035*

The DPPH radical-scavenging activity of edible films based on konjac glucomannan (KGM) polysaccharide loaded with thyme essential oil (TEO) at 0.4, 0.8, 1.2 and 1.6% (*v/v*) increased significantly (*p* < 0.05) with the increase of TEO concentration. Loading KGM-based films with TEO at 1.6% increased its antioxidant capacity by about 50% [72]. They suggested using these films loaded with TEO in food packaging.

Food grade nano-emulsions have been widely used to enhance the water solubility and stability of essential oils [73]. The cellulose nanofibrils films prepared by O/W Pickering emulsion with oregano essential oil exhibit excellent antioxidant activity [74]. They attributed this activity to phenolic compounds of oregano essential oil and recommended these films for packaging of easily oxidized foods.

Cinnamon and clove essential oils improved the antioxidant capacity of mandarin (*Citrus reticulata*) essential oil nanocapsules by 4.43 and 3.52 times, respectively. This increment of antioxidant activity was attributed to the high antioxidant activity of cinnamon and clove essential oils components [75].

Nanoemulsion-based basil seed gum (NBSG) films containing clove essential oil (CEO) had higher antioxidant activity than that of BSG films prepared by conventional method with the same concentration of CEO. The DPPH and ABTS radical scavenging activities of NBSG-CEO films containing 10 mg CEO/mL were not significantly different from those of NBSG-BHT films containing 1 mg BHT/mL. Eugenol is the main constituent of CEO. Wrapping minced camel meat sample with NBSG films containing resveratrol (4 μg/mL) + CEO (10 mg/mL) kept its oxidative stability after 20 days of storage at 4°C better than that of the control group. Peroxide and thiobarbituric acid (TBA) values of the NBSG wrapped meat samples did not exceed 4.03 meq/kg lipid and 1.03 mg malondialdehyde/kg after 20 days of cold storage [76].

Kiralan et al. [77] flavored olive oil with peppermint, oregano, thyme and laurel essential oils at 0.05% (*v/w*). GC-MS analysis of the headspace of flavored samples was carried out after 15, 30, and 45 days of storage at 60°C. The major components of essential oil transferred into olive oil samples. *E*-2-hexenal and hexanal were the main volatile constituents of olive oils during oxidation. After 30 days of thermal oxidation the *E*-2-hexenal level of the control and the peppermint flavored oil exceeded its initial level by 30 and 90 times, respectively. Flavoring olive oil with oregano, thyme and laurel essential oils kept *E*-2-hexenal level in the headspace of flavored samples during thermal oxidation lower than 2 times its original level.

#### **3.2 Essential oil as antimicrobial agent**

EOs with antimicrobial activity inhibit the microbial cells reproductive ability, or damage bacterial cells [78, 79]. Hydrophobicity/lipophilicity property of EOs allows them to cross the cell cytoplasmic membrane and raising permeability of fatty acids, polysaccharides, and phospholipid layers [80]. This causes leakage of cell contents, and loss of macromolecules.

EOs have the ability to coagulate the cytoplasm and inhibit enzymes responsible for the synthesis of biologically active components [81]. Gram positive-bacteria are more sensitive to EOs effect than gram-negative ones, since the outer membrane surrounding the cell wall of gram negative-bacteria, restricts the penetration of EOs through the lipopolysaccharide layer [62].

EOs rich in phenolic compounds like thymol, carvacrol or eugenol display high antimicrobial activities against foodborne pathogens [82, 83]. Aromatic plants that are rich in these phenolic compounds are illustrated in **Figure 4**.

#### **Figure 4.**

*Examples of some aromatic plants rich in thymol, carvacrol and eugenol as phenolic components found in essential oils of these plants.*

These phenolic compounds attack the amine groups in the cell membrane, alter its permeability leading to cell lysis [7, 84]. Moreover, a synergistic effect between EOs components enhances its antimicrobial efficiency. The synergistic effect between ρ-cymene and carvacrol, geraniol and menthol is a good example against wide bacteria range (**Figure 5**).

This antimicrobial efficiency was significantly weaker when each compound acted separately in the same medium. Some EO constituents do not possess antibacterial properties when used alone, but they enhance the bacterial inhibition of other compounds [85].

The incorporation of lemongrass (*Cymbopogon citratus*) essential oil (LEO) into chitosan-based films at 9% level controlled the growth of Gram-positive bacteria (*B. cereus* and *L. monocytogenes*) and Gram-negative bacteria (*E. coli* and *S. typhi*). The antibacterial activity of the films was evaluated using the disk-diffusion method. The chitosan/LEO composite film with 9% LEO completely inhibited the growth of *S. typhi* [86].

Chitosan, gum arabic, and polyethylene glycol composite film incorporated with black pepper essential oil or ginger essential oil possessed high antimicrobial activity against *Bacillus cereus*, *Staphylococcus aureus, Escherichia coli,* and *Salmonella typhimurium* [87].

*Essential Oil as Green Preservative Obtained by Ecofriendly Extraction Techniques DOI: http://dx.doi.org/10.5772/intechopen.103035*

#### **Figure 5.**

*Schematic representation the synergistic effect of ρ-cymene and carvacrol, geraniol and menthol mechanism of action as antimicrobial.*

Fattahian et al. [88] investigated he antimicrobial activity of cumin essential oil (EO) against *Staphylococcus aureus* and *Escherichia coli* O157:H7. They found that *Staphylococcus aureus* was more sensitive to EO than *E. coli* O157:H7. Meanwhile, they studied the effect of coating fresh veal fillets with a biodegradable film of chitosan (CH) incorporated with cumin nanoliposomal EO at 1% level on the microbial properties of veal samples stored in modified atmosphere packages (20% CO2 and 80% O2) at 4°C for 21 days. The total microbial count, lactic acid bacteria, enterobacteriaceae, and pseudomonas were used as microbiological indicators. Encapsulation of cumin EO controlled the release of the antimicrobial compounds on coated samples that extended antimicrobial activity during cold storage for 21 days compared to free EO. At the end of storage, the investigated bacterial strains count of the CH + Nano EO coated samples were lower than those of CH + EO groups. Both coating films kept the bacterial load of meat fillets less than the CH group till the end of storage time.

The antibacterial activity was attributed to cuminaldehyde and the phenolic compounds in cumin essential oil and the synergistic effect of chitosan with EO.

Langroodi et al. [89] coated turkey breast fillet with chitosan incorporated with 1% (*v/v*) of *Origanum vulgare* essential oil and dried ethanolic extract of grape seeds (GSE, 2% *v/v*) before storage at 4°C for 20 days. Alterations in total viable count (TVC), lactic acid bacteria (LAB), Enterobacteriaceae, *Pseudomonas* spp., and yeast-mold counts of cold stored turkey meat samples and sensorial properties of roasted (10 min at 100°C) turkey samples were studied. Incorporation of oregano EO and GSE into chitosan increased the antibacterial activity of the coating film. The TVC counts of control and chitosan coated samples turned unacceptable (>6 CFU/g) after 12 and 16 days of storage, respectively. Coating with chitosan containing oregano essential oil and GSE kept TVC count of the samples less than 5 Log CFU/g after 20 days of storage. At the end of cold storage, the LAB and Enterobacteriaceae counts of samples coated with chitosan-oregano essential oiland GSE were ~ 4 and 4.39 Log CFU/g instead of 7.22 and 7.14 Log CFU/g for the chitosan coated samples, respectively. Furthermore, inclusion of oregano essential oil and GSE into chitosan coating reduced the Pseudomonads counts in the samples by ~3 Log CFU/g, at the end of storage time. Application of oregano EO at 1% level and GSE at 2% enhanced the antifungal activity of chitosan coating. Yeast-mold count of turkey meat samples coated with chitosan-oregano EO-GSE did not exceed 4.27 Log CFU/g at the end of storage time. They attributed this strong antibacterial activity of the coating film to the synergistic effect of oregano EOs and GSE. CH-GSE 2%-O coated samples depicted the highest consumer scores compared with other samples till the end of storage.

Sayadi et al. [90] packaged fresh chicken pieces (2 cm thickness and 20 cm length) in plain and nano composite edible films of gelatin (GE) containing 1% TiO2 nanoparticles (GE + TiO2), 2% cumin essential oil (GE + CEO), and 1% TiO2 + 2% CEO (GE + TiO2 + CEO) before storing in polyethylene plastic bags at 4 ± 1°C for 24 days. The population of total mesophilic bacteria, Enterobacteriaceae, lactic acid bacteria, and *Pseudomonas* spp., of packaged samples were evaluated. The bacterial growth (for different bacteria) in the control increased by ≥4 log CFU/g, after 24 days of storage. At the end of storage time the lowest population (<6 log CFU/g) of the tested bacteria was recorded for GE + CEO and GE + TiO2 + CEO chicken samples. They attributed the antimicrobial activity to cuminaldehyde component and phenolic compounds of CEO in addition to reactive oxygen species generated by TiO2-N that disrupt the bacteria membrane. Although the GE + CEO and GE + TiO2 + CEO groups obtained the highest sensory scores among chicken samples, both groups showed unacceptable scores of sensory attributes (odor and overall acceptability) after 16 days of storage.

Sharma et al. [91] tested essential oils of clove bud, tagetes, thyme, eucalyptus, neem, cinnamon leaf, himalayan pine needle, and tea tree against the total bread molds by agar well-diffusion method. Thyme oil completely inhibited the growth of bread molds than other essential oils. They found that sealing fresh white slices of bread in a biodegradable film (poly, 3-hydroxybutyrate-co-4-hydroxybutyrate) incorporated with thyme essential oil at 30% (*v/w*) extended its shelf-life against molds to >5 days at ambient conditions (25–28°C and 35–45% RH), compared to 1–4 days in neat biopolymer film. The molds count of the bread packaged in this film after 5 days of storage was *<*1.00 log (CFU/mL), the same level at the zerotime storage.

#### **3.3 Essential oil as flavoring agent**

Flavoring is one of the main application of essential oils in the food and beverage industries [81]. Flavorings are used to improve the odor of foods in order to satisfy the consumer. EOs are used in the preparation of carbonated beverage to give the product its distinctive aroma.

Recently, flavored edible oils are produced in order to improve its sensory properties [92, 93]. Flavoring of oils is carried out by infusion or maceration of the aromatic plant into the oil [94, 95]. Theses flavoring techniques enhance the extraction of waxes and undesirable components into oil [96]. To overcome these defects, EOs have been used as flavoring materials [97]. However, strong flavors with some EOs may negatively affect the consumer acceptability of the food. The flavoring of edible oils improves their sensory properties [92], increase their use for the preparation of daily food condiments [98] and extend their usage by non-traditional consumers [99].

Porto and Decorti [100] flavored ricotta cheese with thyme essential oil by mixing at 0.26, 0.33 and 0.40% (*w/w*). The main constituents of the essential oil were carvacrol, carvacrol methyl ether, ρ-cymene, γ-terpinene and thymol. Sensory studies indicated that the minimum perception level of thyme essential oil in ricotta cheese was 0.20% (*w/w*). Aroma compounds of the flavored ricotta cheese were extracted by Headspace solid-phase micro-extraction at 30°C and were identified with GC-MS. Results showed that hydrocarbons monoterpene and hydrocarbons sesquiterpene were lower in the headspace of ricotta by 25% and 40%, respectively, compared to their original level in essential oil. They attributed these decrements to the binding capacity of fat and proteins to flavor compounds.

Benkhoud et al. [101] flavored extra virgin olive oil by homogenization with Eos (500 ppm) of thyme, rosemary, black pepper, fennel, and citrus peels. Flavored oil samples were stored for 12 months, at room temperature. The headspace of flavored oil enriched mainly with the major components of the flavoring essential oils. They attributed the bitterness of rosemary, thyme, and fennel flavored samples to the presence of 1,8-cineole and carvacrol while pungency of black pepper flavored samples was ascribed to β-caryophyllene and α-phellandrene. Citrus-flavored oil samples were distinguished by their fruity taste due to limonene. The highest acceptability scores were recorded for fennel and citrus flavored oil samples.

Moustakime et al. [99] flavored virgin olive oil (VOO) with the seeds of green anise. The main component of the anise seeds EO was found to be *trans*-anethole (76.16%). This compound was used as an indicator for the level of flavoring. Flavoring of VOO was carried out with anise seeds at a ratio of 15% (w/w) with maceration, sonication (intensity ~1 W/cm<sup>2</sup> ) and direct addition of the EO (0.33 mL, equivalent to amount of oil from 15 g seeds) using stirring for 24 h. GC/MS analysis indicated that the diffusible *trans*-anethole reached 26.59% of the total volatile fraction of the flavored oil after 15 min of ultrasound treatment instead of 23.85% after 9 days of maceration. Meanwhile, *trans*-anethole level of the total volatile fraction reached 36.3% by direct addition of EO.

#### **4. Conclusions**

The ecofriendly techniques meet the terms of green extraction, reduces extraction time, with high yield, low energy consumption and solvent amount, allows the use

of renewable natural products, and ensures a safe and high-quality essential oil. The addition of essential oils to food as green preservative causes many positive effects such as antioxidant, antimicrobial activities and improve the flavor in food products. This effect could be due to the synergistic combination of the essential oil constituents rather than one component.

### **Conflict of interest**

"The authors declare no conflict of interest."

### **Thanks**

I would like to express my special thanks and gratitude to Professor Samy Mohamed Galal, Food Science Department, Faculty of Agriculture, Cairo University, who encouraged me to write this chapter, and he also helped me in revising it. I appreciated his efforts.

### **Author details**

Nashwa Fathy Sayed Morsy Faculty of Agriculture, Food Science Department, Cairo University, Giza, Egypt

\*Address all correspondence to: nanafsm@yahoo.com

© 2022 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

*Essential Oil as Green Preservative Obtained by Ecofriendly Extraction Techniques DOI: http://dx.doi.org/10.5772/intechopen.103035*

#### **References**

[1] Liu XY, Ou H, Xiang ZB, Gregersen H. Optimization, chemical constituents and bioactivity of essential oil from *Iberis amara* seeds extracted by ultrasound assisted hydro-distillation compared to conventional techniques. Journal of Applied Research on Medicinal and Aromatic Plants. 2019;**13**:100204. DOI: 10.1016/j.jarmap.2019.100204

[2] Ferhat MA, Meklati BY, Smadja J, Chemat F. An improved microwave Clevenger apparatus for distillation of essential oils from orange peel. Journal of Chromatography A. 2006;**1112**:121-126. DOI: 10.1016/j.chroma.2005.12.030

[3] Mohamad N, Ramli N, Abd-Aziz S, Ibrahim MF. Comparison of hydrodistillation, hydro-distillation with enzyme-assisted and supercritical fluid for the extraction of essential oil from pineapple peels. 3 Biotech. 2019;**9**:234. DOI: 10.1007/s13205-019-1767-8

[4] Huang P, Gu Z, Yang L, Yang R, Ji Y, Zeng Q, et al. Study on optimization of extraction technique of pericarp essential oil in *Litsea Cubeba* (Lour) Pers. Journal of Food Measurement and Characterization. 2021;**15**:758-768. DOI: 10.1007/s11694-020-00657-0

[5] Fernández-López J, Viuda-Martos M. Introduction to the special issue: Application of essential oils in food systems. Foods. 2018;**7**(4):56. DOI: 10.3390/foods7040056

[6] Pelaes Vital AC, Guerrero A, Guarnido P, Cordeiro Severino I, Olleta JL, Blasco M, et al. Effect of activeedible coating and essential oils on lamb patties oxidation during display. Foods. 2021;**10**(2):263. DOI: 10.3390/ foods10020263

[7] Hyldgaard M, Mygind T, Meyer RL. Essential oils in food preservation: Mode of action, synergies, and interactions with food matrix components. Frontiers in Microbiology. 2012;**3**:1-24. DOI: 10.3389/fmicb.2012. 00012

[8] Simionato I, Domingues FC, Nerín C, Silva F. Encapsulation of cinnamon oil in cyclodextrin nanosponges and their potential use for antimicrobial food packaging. Food and Chemical Toxicology. 2019;**132**:110647. DOI: 10.1016/j.fct.2019.110647

[9] Chaudhari AK, Dwivedy AK, Singh VK, Das S, Singh A, Dubey NK. Essential oils and their bioactive compounds as green preservatives against fungal and mycotoxin contamination of food commodities with special reference to their nanoencapsulation. Environmental Science and Pollution Research. 2019;**26**:25414-25431. DOI: 10.1007/ s11356-019-05932-2

[10] Rao MV, Sengar AS, Sunil CK, Rawson A. Ultrasonication—A green technology extraction technique for spices: A review. Trends in Food Science and Technology. 2021;**116**:975-991. DOI: 10.1016/j.tifs.2021.09.006

[11] Muhammad DRA, Tuenter E, Patria GD, Foubert K, Pieters L, Dewettinck K. Phytochemical composition and antioxidant activity of *Cinnamomum burmannii* Blume extracts and their potential application in white chocolate. Food Chemistry. 2021;**340**:127983. DOI: 10.1016/j. foodchem.2020.127983

[12] Arya P, Kumar P. Comparison of ultrasound and microwave assisted extraction of diosgenin from *Trigonella foenum graceum* seed. Ultrasonics Sonochemistry. 2021;**74**:105572. DOI: 10.1016/j.ultsonch.2021.105572

[13] Chemat F, Rombaut N, Sicaire AG, Meullemiestre A, Fabiano-Tixier AS, Abert-Vian M. Ultrasound assisted extraction of food and natural products. Mechanisms, techniques, combinations, protocols and applications. A review. Ultrasonics Sonochemistry. 2017;**34**:540- 560. DOI: 10.1016/j.ultsonch.2016.06.035

[14] Chen G, Sun F, Wang S, Wang W. Enhanced extraction of essential oil from *Cinnamomum cassia* bark by ultrasound assisted hydrodistillation. Chinese Journal of Chemical Engineering. 2020;**36**:38-46. DOI: 10.1016/j. cjche.2020.08.007

[15] Lilia C, Abdelkader A, Karima AKA, Tarek B. The effect of ultrasound pre-treatment on the yield, chemical composition and antioxidant activity of essential oil from Wild *Lavandula stoechas* L. Journal of Essential Oil Bearing Plants. 2018;**21**:253-263. DOI: 10.1080/0972060X.2018.1432419

[16] Wu Y, Jiang X, Zhang L, Zhou Y. Ultrasonic-assisted extraction, comparative chemical composition and biological activities of essential oils of fresh and dry aboveground parts of *Artemisia annua* L. Journal of Essential Oil Bearing Plants. 2018;**21**:1624-1635. DOI: 10.1080/0972060X.2019.1574244

[17] Jadhav NL, Garule PA, Pinjari DV. Comparative study of ultrasound pretreatment method with conventional hydrodistillation method for extraction of essential oil from *Piper betle* L. (Paan). Indian Chemical Engineer. 2020. DOI: 10.1080/00194506.2020.1828193

[18] Ghule SN, Desai MA. Intensified extraction of valuable compounds from clove buds using ultrasound assisted hydrotropic extraction. Journal of Applied Research on Medicinal and Aromatic Plants. 2021;**25**:100325. DOI: 10.1016/j.jarmap.2021.100325

[19] Guo J, Yang R, Gong Y, Hu K, Hu Y, Song F. Optimization and evaluation of the ultrasound-enhanced subcritical water extraction of cinnamon bark oil. LWT—Food Science and Technology. 2021;**147**:111673. DOI: 10.1016/j. lwt.2021.111673

[20] Zhang X, Zhu H, Wang J, Li F, Wang J, Ma X, et al. Anti-microbial activity of citronella (*Cymbopogon citratus*) essential oil separation by ultrasound assisted ohmic heating hydrodistillation. Industrial Crops and Products. 2022;**176**:114299. DOI: 10.1016/j.indcrop.2021.114299

[21] Reis NS, Brito AR, Pacheco CSV, Costa LCB, Gross E, Santos TP, et al. Improvement in menthol extraction of fresh leaves of *Mentha arvensis* by the application of multi-enzymatic extract of *Aspergillus niger*. Chemical Engineering Communications. 2019;**206**:387-397. DOI: 10.1080/00986445.2018.1494580

[22] Liu Z, Li H, Cui G, Wei M, Zou Z, Ni H. Efficient extraction of essential oil from *Cinnamomum burmannii* leaves using enzymolysis pretreatment and followed by microwave-assisted method. LWT—Food Science and Technology. 2021;**147**:111497. DOI: 10.1016/j. lwt.2021.111497

[23] Gligor O, Mocan A, Moldovan C, Locatelli M, Crișan G, Ferreira ICFR. Enzyme-assisted extractions of polyphenols: A comprehensive review. Trends in Food Science and Technology. 2019;**88**:302-315. DOI: 10.1016/j. tifs.2019.03.029

[24] Patil PD, Patil SP, Kelkar RK, Patil NP, Pise PV, Nadar SS. Enzymeassisted supercritical fluid extraction: An integral approach to extract bioactive compounds. Trends in Food Science and Technology. 2021;**116**:357-369. DOI: 10.1016/j.tifs.2021.07.032

*Essential Oil as Green Preservative Obtained by Ecofriendly Extraction Techniques DOI: http://dx.doi.org/10.5772/intechopen.103035*

[25] Chiang CF, Lai LS. Effect of enzyme-assisted extraction on the physicochemical properties of mucilage from the fronds of *Asplenium australasicum* (J. Sm.) Hook. International Journal of Biological Macromolecules. 2019;**124**:346-353. DOI: 10.1016/j.ijbiomac.2018.11.181

[26] Mahmoudi H, Marzouki M, M'Rabet Y, Mezni M, Ait Ouazzou A, Hosni K. Enzyme pretreatment improves the recovery of bioactive phytochemicals from sweet basil (*Ocimum basilicum* L.) leaves and their hydrodistilled residue by-products, and potentiates their biological activities. Arabian Journal of Chemistry. 2020;**13**:6451-6460. DOI: 10.1016/j.arabjc.2020.06.003

[27] Li Z, Wang H, Pan X, Guo Y, Gao W, Wang J, et al. Enzyme-deep eutectic solvent pre-treatment for extraction of essential oil from *Mentha haplocalyx* Briq. leaves: Kinetic, chemical composition and inhibitory enzyme activity. Industrial Crops and Products. 2022;**177**:114429. DOI: 10.1016/j. indcrop.2021.114429

[28] Pontillo ARN, Papakosta-Tsigkri L, Lymperopoulou T, Mamma D, Kekos D, Detsi A. Conventional and enzymeassisted extraction of rosemary leaves (*Rosmarinus officinalis* L.): Toward a greener approach to high added-value extracts. Applied Sciences. 2021;**11**:3724. DOI: 10.3390/app11083724

[29] Picot-Allain C, Mahomoodally MF, Ak G, Zengin G. Conventional versus green extraction techniques: A comparative perspective. Current Opinion in Food Science. 2021;**40**: 144-156. DOI: 10.1016/j.cofs.2021.02.009

[30] Hosni K, Hassen I, Chaabane H, Jemli M, Dallali S. Enzyme-assisted extraction of essential oils from thyme (*Thymus capitatus* L.) and rosemary

(*Rosmarinus officinalis* L.): Impact on yield, chemical composition and antimicrobial activity. Industrial Crops and Products. 2013;**47**:291-299. DOI: 10.1016/j.indcrop.2013.03.023

[31] Baby KC, Ranganathan TV. Effect of enzyme pre-treatment on extraction yield and quality ofcardamom (*Elettaria cardamomum* maton.) volatile oil. Industrial Crops and Products. 2016a;**89**:200-206. DOI: 10.1016/j. indcrop.2016.05.017

[32] Baby KC, Ranganathan TV. Effect of enzyme pre-treatment on extraction yield and quality of fennel (*Foeniculum vulgare*) volatile oil. Biocatalysis and Agricultural Biotechnology. 2016b;**8**: 248-256. DOI: 10.1016/j.bcab.2016.10.001

[33] Shimotori Y, Watanabe T, Kohari Y, Chiou T, Ohtsu N, Nagata Y, et al. Enzyme-assisted extraction of bioactive phytochemicals from Japanese peppermint (*Mentha arvensis* L. cv. 'Hokuto'). Journal of Oleo Science. 2020;**69**(6):635-642. DOI: 10.5650/jos. ess19181

[34] Morsy NFS, Hammad KSM. Extraction of essential oil from methyl cinnamate basil (*Ocimum canum* Sims) with high yield in a short time using enzyme pretreatment. Journal of Science and Technology. 2021;**58**(7):2599-2605. DOI: 10.1007/s13197-020-04766-y

[35] Vladić J, Duarte ARC, Radman S, Simić S, Jerković I. Enzymatic and microwave pretreatments and supercritical CO2 extraction for improving extraction efficiency and quality of *Origanum vulgare* L. spp. hirtum extracts. Plants. 2022;**11**:54. DOI: 10.3390/plants11010054

[36] Memarzadeh SM, Pirbalouti AG, AdibNejad M. Chemical composition and yield of essential oils from Bakhtiari savory (*Satureja bachtiarica* Bunge.) under different extraction methods. Industrial Crops and Products. 2015;**76**:809-816. DOI: 10.1016/j. indcrop.2015.07.068

[37] Kazemi M, Niazi A, Yazdanipour A. Extraction of *Satureja rechingeri* volatile components through ultrasoundassisted and microwave-assisted extractions and comparison of the chemical composition with headspace solid-phase microextraction. Journal of Essential Oil Research. 2022;**34**. DOI: 10.1080/10412905.2021.1975575

[38] Hassanein HD, El-Gendy AE-NG, Saleh IA, Hendawy SF, Elmissiry MM, Omer EA. Profiling of essential oil chemical composition of some Lamiaceae species extracted using conventional and microwave-assisted hydrodistillation extraction methods via chemometrics tools. Flavour and Fragrance Journal. 2020;**35**:329-340. DOI: 10.1002/ffj.3566

[39] Ghazanfari N, Mortazavi SA, Yazdi FT, Mohammadi M. Microwaveassisted hydrodistillation extraction of essential oil from coriander seeds and evaluation of their composition, antioxidant and antimicrobial activity. Heliyon. 2020;**6**:e04893. DOI: 10.1016/j. heliyon.2020.e04893

[40] Memarzadeh SM, Gholami A, Pirbalouti AG, Masoum S. Bakhtiari savory (*Satureja bachtiarica* Bunge.) essential oil and its chemical profile, antioxidant activities, and leaf micromorphology under green and conventional extraction techniques. Industrial Crops and Products. 2020;**154**:112719. DOI: 10.1016/j. indcrop.2020.112719

[41] Yingngam B, Navabhatra A, Brantner A. Increasing the essential oil yield from *Shorea roxburghii* inflorescences using an eco-friendly solvent-free microwave extraction method for fragrance applications. Journal of Applied Research on Medicinal and Aromatic Plants. 2021;**24**:100332. DOI: 10.1016/j.jarmap.2021.100332

[42] Yingngam B, Brantner A, Treichler M, Brugger N, Navabhatra A, Nakonrat P. Optimization of the eco-friendly solvent-free microwave extraction of *Limnophila aromatica* essential oil. Industrial Crops and Products. 2021;**165**:113443. DOI: 10.1016/j.indcrop.2021.113443

[43] Peng X, Yang X, Gu H, Yang L, Gao H. Essential oil extraction from fresh needles of *Pinus pumila* (Pall.) Regel using a solvent-free microwaveassisted methodology and an evaluation of acetylcholinesterase inhibition activity in vitro compared to that of its main components. Industrial Crops and Products. 2021;**167**:113549. DOI: 10.1016/j.indcrop.2021.113549

[44] Khaw KY, Parat MO, Shaw PN, Falconer JR. Solvent supercritical fluid technologies to extract bioactive compounds from natural sources: A review. Molecules. 2017;**22**:1186. DOI: 10.3390/molecules22071186

[45] Yousefi M, Rahimi-Nasrabadi M, Pourmortazavi SM, Wysokowski M, Jesionowski T, Ehrlich H, et al. Supercritical fluid extraction of essential oils. TrAC Trends in Analytical Chemistry. 2019;**118**:182-193. DOI: 10.1016/j. trac.2019.05.038

[46] Cvjetko M, Jokić S, Lepojević Ž, Vidović S, Marić B, Redovniković IR. Optimization of the supercritical CO2 extraction of oil from rapeseed using response surface methodology. Food Technology and Biotechnology. 2012;**50**:208-215

[47] Somaris E, Quintana SE, Llalla O, Garcia-Risco MR, Fornari T. Comparison *Essential Oil as Green Preservative Obtained by Ecofriendly Extraction Techniques DOI: http://dx.doi.org/10.5772/intechopen.103035*

between essential oils and supercritical extracts into chitosan based edible coatings on strawberry quality during cold storage. The Journal of Supercritical Fluids. 2021;**171**:105198. DOI: 10.1016/j. supflu.2021.105198

[48] Fornari T, Vicente G, Vázquez E, García-Risco MR, Reglero G. Isolation of essential oil from different plants and herbs by supercritical fluid extraction. Journal of Chromatography A. 2012;**1250**:34-48. DOI: 10.1016/j. chroma.2012.04.051

[49] Bubalo CM, Vidović S, Redovniković IR, Jokić S. New perspective in extraction of plant biologically active compounds by green solvents. Food and Bioproducts Processing. 2018;**109**:52-73. DOI: 10.1016/j.fbp.2018.03.001

[50] Xiong K, Chen Y. Supercritical carbon dioxide extraction of essential oil from tangerine peel: Experimental optimization and kinetics modelling. Chemical Engineering Research and Design. 2020;**164**:412-423. DOI: 10.1016/j.cherd.2020.09.032

[51] Uwineza PA, Waskiewicz A. Recent advances in supercritical fluid extraction of natural bioactive compounds from natural plant materials. Molecules. 2020;**25**:3847. DOI: 10.3390/ molecules25173847

[52] Leila M, Ratiba D, Al-Marzouqi A-H. Experimental and mathematical modelling data of green process of essential oil extraction: Supercritical CO2 extraction. Materials Today: Proceedings. 2022;**49**:1023-1029. DOI: 10.1016/j. matpr.2021.08.125

[53] Markom M, Hassim N, Anuar N, Baharum S. Co-solvent selection for supercritical fluid extraction of essential oil and bioactive compounds from

*Polygonum minus*. ASEAN Journal of Chemical Engineering. 2013;**12**:19-26. DOI: 10.22146/ajche.49739

[54] Ara KM, Jowkarderis M, Raofie F. Optimization of supercritical fluid extraction of essential oils and fatty acids from flixweed (*Descurainia sophia* L.) seed using response surface methodology and central composite design. Journal of Food Science and Technology. 2015;**52**:4450-4458. DOI: 10.1007/s13197-014-1353-3

[55] Oliveira MS, da Cruz JN, Silva SG, da Costa WA, de Sousa SHB, Bezerra FWF, et al. Phytochemical profile, antioxidant activity, inhibition of acetylcholinesterase and interaction mechanism of the major components of the *Piper divaricattun* essential oil obtained by supercritical CO2. The Journal of Supercritical Fluids. 2019;**145**:74-84. DOI: 10.1016/j. supflu.2018.12.003

[56] Marzlan AA, Muhialdin BJ, Abedin NHZ, Mohammed NK, Abadl MMT, Roby BHM, et al. Optimized supercritical CO2 extraction conditions on yield and quality of Torch Ginger (*Etlingera Elatior* (Jack) RM Smith) inflorescence essential oil. Industrial Crops and Products. 2020;**154**:112581. DOI: 10.1016/j. indcrop.2020.112581

[57] Silva SG, de Oliveira MS, Cruz JN. Supercritical CO2 extraction to obtain *Lippia thymoides* Mart. & Schauer (Verbenaceae) essential oil rich in thymol and evaluation of its antimicrobial activity. The Journal of Supercritical Fluids. 2021;**168**:105064. DOI: 10.1016/j. supflu.2020.105064

[58] Amorati R, Foti MC, Valgimigli L. Antioxidant activity of essential oils. Journal of Agricultural and Food Chemistry. 2013;**61**(46):10835-10847. DOI: 10.1021/jf403496k

[59] Maqsood S, Benjakul S, Abushelaibi A, Alam A. Phenolic compounds and plant phenolic extracts as natural antioxidants in prevention of lipid oxidation in seafood: A detailed review. Comprehensive Reviews in Food Science and Food Safety. 2014;**13**(6):1125-1140. DOI: 10.1111/1541-4337.12106

[60] Tongnuanchan P, Benjakul S. Essential oils: Extraction, bioactivities, and their uses for food preservation. Journal of Food Science. 2014;**79**(7): R1231-R1249. DOI: 10.1111/1750-3841. 12492

[61] Prakash B, Kedia A, Mishra PK, Dubey NK. Plant essential oils as food preservatives to control moulds, mycotoxin contamination and oxidative deterioration of agri-food commodities e Potentials and challenges. Food Control. 2015;**47**:381-391. DOI: 10.1016/j. foodcont.2018. 01.018

[62] Rodriguez-Garcia I, Espinoza AS, Ortega Ramirez A, Leyva M, Siddiqui W, Cruz-Valenzuela R, et al. Oregano essential oil as an antimicrobial and antioxidant additive in food products. Critical Reviews in Food Science and Nutrition. 2016;**56**:1717-1727. DOI: 10.1080/10408398.2013.800832

[63] De Souza WFM, Mariano XM, Isnard JL, De Souza GS, De Souza Gomes AL, De Carvalho RJT, et al. Evaluation of the volatile composition, toxicological and antioxidant potentials of the essential oils and teas of commercial Chilean boldo samples. Food Research International. 2019;**124**:27-33. DOI: 10.1016/j.foodres.2018.12.059

[64] Sharma H, Mendiratta SK, Kant R, Gurunathan K, Kumar S, Pal T. Use of various essential oils as bio preservatives and their effect on the quality of vacuum packaged fresh chicken sausages under frozen conditions. LWT—Food Science

and Technology. 2017;**81**:118-127. DOI: 10.1016/j.lwt.2017.03.048

[65] Dastgerdi GF, Goli SAH, Kadivar M. New antioxidant active film based on HDPE and peppermint essential oil for packaging soybean oil. Journal of the American Oil Chemists' Society. 2016;**93**:657-664. DOI: 10.1007/ s11746-016-2806-9

[66] Mezza GN, Borgarello AV, Grosso NR, Fernandez H, Pramparo MC, Gayol MF. Antioxidant activity of rosemary essential oil fractions obtained by molecular distillation and their effect on oxidative stability of sunflower oil. Food Chemistry. 2018;**242**:9-15. DOI: 10.1016/j.foodchem.2017.09.042

[67] Okhli S, Mirzaei H, Hosseini SE. Antioxidant activity of citron peel (*Citrus medica* L.) essential oil and extract on stabilization of sunflower oil. Oilseeds & Fats Crops and Lipids. 2020;**27**:32. DOI: 10.1051/ocl/2020022

[68] Bensid A, Ucar Y, Bendeddouche B, Ozogul F. Effect of the icing with thyme, oregano and clove extracts on quality parameters of gutted and beheaded anchovy (*Engraulis encrasicholus*) during chilled storage. Food Chemistry. 2014;**145**:681-686. DOI: 10.1016/j. foodchem.2013.08.106

[69] Karoui R, Hassoun A. Efficiency of rosemary and basil essential oils on the shelf-life extension of atlantic mackerel (*Scomber Scombrus*) fillets stored at 2°C. Journal of AOAC International. 2017;**100**:335-344. DOI: 10.5740/ jaoacint.16-0410

[70] Boskovic M, Glisic M, Djordjevic J, Starcevic M, Glamoclija N, Djordjevic V, et al. Antioxidative activity of Thyme (*Thymus vulgaris*) and Oregano (*Origanum vulgare*) essential oils and their effect on oxidative stability of

*Essential Oil as Green Preservative Obtained by Ecofriendly Extraction Techniques DOI: http://dx.doi.org/10.5772/intechopen.103035*

minced pork packaged under vacuum and modified atmosphere. Journal of Food Science. 2019;**84**(9):2467-2474. DOI: 10.1111/1750-3841.14788

[71] Ishkeh SR, Asghari M, Shirzad H, Alirezalu A, Ghasemi G. Lemon verbena (*Lippia citrodora*) essential oil effects on antioxidant capacity and phytochemical content of raspberry (*Rubus ulmifolius* subsp. sanctus). Scientia Horticulturae. 2019;**248**:297-304. DOI: 10.1016/j. scienta.2018.12.040

[72] Liu Z, Lin D, Shen R, Zhang R, Liu L, Yang X. Konjac glucomannan-based edible films loaded with thyme essential oil: Physical properties and antioxidantantibacterial activities. Food Packaging and Shelf Life. 2021;**29**:100700. DOI: 10.1016/j.fpsl.2021.100700

[73] Hien LTM, Dao DTA. Black pepper essential oil nanoemulsions formulation using EPI and PIT methods. Journal of Food Processing and Preservation. 2021;**45**(3):e15216. DOI: 10.1111/ jfpp.15216

[74] Wu M, Zhou Z, Yang J, Zhang M, Cai F, Lu P. ZnO nanoparticles stabilized oregano essential oil Pickering emulsion for functional cellulose nanofibrils packaging films with antimicrobial and antioxidant activity. International Journal of Biological Macromolecules. 2021;**190**:433-440. DOI: 10.1016/j. ijbiomac.2021.08.210

[75] Mahdi AA, Al-Maqtari QA, Mohammed JK, Al-Ansi W, Cui H, Lin L. Enhancement of antioxidant activity, antifungal activity, and oxidation stability of *Citrus reticulata* essential oil nanocapsules by clove and cinnamon essential oils. Food Bioscience. 2021;**43**:101226. DOI: 10.1016/j. fbio.2021.101226

[76] Ansarian E, Aminzare M, Azar HH, Mehrasbi MR, Bimakr M. Nanoemulsion-based basil seed gum edible film containing resveratrol and clove essential oil: In vitro antioxidant properties and its effect on oxidative stability and sensory characteristic of camel meat during refrigeration storage. Meat Science. 2022;**185**:108716. DOI: 10.1016/j.meatsci.2021.108716

[77] Kiralan SS, Karagoz SG, Ozkan G, Kiralan M, Ketenoglu O. Changes in volatile compounds of virgin olive oil flavored with essential oils during thermal and photo-oxidation. Food Analytical Methods. 2021;**14**:883-896. DOI: 10.1007/s12161-020-01926-w

[78] Calo JR, Crandall PG, O'Bryan CA, Ricke SC. Essential oils as antimicrobials in food systems: A Review. Food Control. 2014;**54**:111-119. DOI: 10.1016/j. foodcont.2014.12.040

[79] Dhifi W, Bellili S, Jazi S, Bahloul N, Mnif W. Essential oils' chemical characterization and investigation of some biological activities: A critical review. Medecines. 2016;**3**:1-16. DOI: 10.3390/medicines 3040025

[80] Falleh H, Jemaa MB, Saada M, Ksouri R. Essential oils: A promising eco-friendly food preservative. Food Chemistry. 2020;**330**:127268. DOI: 10.1016/j.foodchem.2020.127268

[81] Burt S. Essential oils: Their antibacterial properties and potential applications in foods: A review. International Journal of Food Microbiology. 2004;**94**:223-253. DOI: 10.1016/j.ijfoodmicro.2004.03.022

[82] Ben Jemaa M, Falleh H, Saada M, Oueslati M, Snoussi M, Ksouri R. *Thymus capitatus* essential oil ameliorates pasteurized milk quality. Journal of Food Science and Technology. 2018;**55**(9):3446-3452. DOI: 10.1007/ s13197-018-3261-4

[83] Gutiérrez-del-Río I, Fernández J, Lombó F. Plant nutraceuticals as antimicrobial agents in food preservation: Terpenoids, polyphenols and thiols. International Journal of Antimicrobial Agents. 2018;**52**:309-315. DOI: 10.1016/j. ijantimicag.2018.04.024

[84] Adelakun OE, Oyelade OJ, Olanipekun BF. Use of essential oils in food preservation. In: Preedy VR, editor. Essential Oils in Food Preservation, Flavor, and Safety. London: Elsevier; 2016. pp. 71-84. DOI: 10.1016/C2012-0-06581-7

[85] Hussain MA, Sumon TA, Mazumder SK, Ali MM, Jang WJ, Abualreesh MH, et al. Essential oils and chitosan as alternatives to chemical preservatives for fish and fisheries products: A review. Food Control. 2021;**129**:108244. DOI: 10.1016/j. foodcont.2021.108244

[86] Han Lyn F, Nur Hanani ZA. Effect of Lemongrass (*Cymbopogon citratus*) essential oil on the properties of chitosan films for active packaging. Journal of Packaging Technology and Research. 2020;**4**(1):33-44. DOI: 10.1007/ s41783-019-00081-w

[87] Amalraj A, Raj KKJ,

Haponiuk JT, Thomas S, Gopi S. Preparation, characterization, and antimicrobial activity of chitosan/gum arabic/ polyethylene glycol composite films incorporated with black pepper essential oil and ginger essential oil as potential packaging and wound dressing materials. Advanced Composites and Hybrid Materials. 2020;**3**:485-497. DOI: 10.1007/ s42114-020-00178-w

[88] Fattahian A, Fazlara A, Maktabi S, Pourmahdi M, Bavarsad N. The effects of chitosan containing nano-capsulated *Cuminum cyminum* essential oil on the shelf-life of veal in modified atmosphere packaging. Journal of Food

Measurement and Characterization. 2021. DOI: 10.1007/s11694-021-01213-0

[89] Langroodi AM, Nematollahi A, Sayadi M. Chitosan coating incorporated with grape seed extract and *Origanum vulgare* essential oil: An active packaging for turkey meat preservation. Journal of Food Measurement and Characterization. 2021;**15**:2790-2804. DOI: 10.1007/s11694-021-00867-0

[90] Sayadi M, Amiri S, Radi M. Active packaging nanocomposite gelatinbased films as a carrier of nano TiO2 and cumin essential oil: The effect on quality parameters of fresh chicken. Journal of Food Measurement and Characterization. 2021. DOI: 10.1007/ s11694-021-01169-1

[91] Sharma P, Ahuja A, Izrayeel AMD, Samyn P, Rastogi VK. Physicochemical and thermal characterization of poly (3-hydroxybutyrate-co-4 hydroxybutyrate) films incorporating thyme essential oil for active packaging of white bread. Food Control. 2022;**133**:108688. DOI: 10.1016/j. foodcont.2021.108688

[92] Caponio F, Durante V, Varva G, Silletti R, Previtali MA, Viggiani I, et al. Effect of infusion of spices into the oil vs. combined malaxation of olive paste and spices on quality of naturally flavoured virgin olive oils. Food Chemistry. 2016;**202**:221-228. DOI: 10.1016/j. foodchem.2016.02.005

[93] Yilmazer M, Karagöz SG, Ozkan G, Karacabey E. Aroma transition from rosemary leaves during aromatization of olive oil. Journal of Food and Drug Analysis. 2016;**24**:299-304. DOI: 10.1016/j.jfda.2015.11.002

[94] Sousa A, Casal S, Malheiro R, Lamas H, Bento A, Pereira JA. Aromatized olive oils: Influence of *Essential Oil as Green Preservative Obtained by Ecofriendly Extraction Techniques DOI: http://dx.doi.org/10.5772/intechopen.103035*

flavouring in quality, composition, stability, antioxidants, and antiradical potential. LWT—Food Science and Technology. 2015;**60**(1):22-28. DOI: 10.1016/j.lwt.2014.08.026

[95] Perestrelo R, Silva C, Silva P, Câmara JS. Global volatile profile of virgin olive oils flavoured by aromatic/ medicinal plants. Food Chemistry. 2017;**227**:111-121. DOI: 10.1016/j. foodchem.2017.01.090

[96] Baiano A, Gambacorta G, La Notte E. Aromatization of olive oil. Transworld Research Network. 2010;**661**:1-29

[97] Arcoleo G, Indovina MC, Varvara G, Lanza CM, Mazzaglia A. Improving olive oil shelf life with lemon essential oil. Chemical Engineering Transactions. 2009;**17**:849-854. DOI: 10.3303/ CET0917142

[98] Wang D, Fan W, Guan Y, Huang H, Yi T, Ji J. Oxidative stability of sunflower oil flavored by essential oil from *Coriandrum sativum* L. during accelerated storage. LWT—Food Science and Technology. 2018;**98**:268-275. DOI: 10.1016/j.lwt.2018.08.055

[99] Moustakime Y, Hazzoumi Z, Joutei KA. Aromatization of virgin olive oil by seeds of *Pimpinella anisum* using three different methods: Physicochemical change and thermal stability of flavored oils. Grain and Oil Science and Technology. 2021;**4**:108-124. DOI: 10.1016/j.gaost.2021.07.001

[100] Porto CD, Decorti D. Analysis of the volatile compounds of aerial parts and essential oil from *Thymus serpyllum* L. cultivated in North East Italy by HS-SPME/GC-MS and evaluation of its flavouring effect on Ricotta cheese. Journal of Essential Oil Bearing Plants. 2012;**15**:561-571. DOI: 10.1080/0972060X.2012.10644089 [101] Benkhoud H, M'Rabet Y, Ali MG, Mezni M, Hosni K. Essential oils as flavoring and preservative agents: Impact on volatile profile, sensory attributes, and the oxidative stability of flavored extra virgin olive oil. Journal of Food Processing and Preservation;**2021**:e15379 10.1111/jfpp.15379

### Section 2
