**3.2 Protein-based edible films**

In recent years, protein-based edible films have drawn interest due to their advantages over synthetic films, including their usage as edible packaging materials. Furthermore, protein-based edible films can be utilized for the individual packaging of tiny amounts of food, particularly goods that are not currently wrapped individually for practical reasons, such as beans, almonds, and cashew nuts. In addition, protein-based edible films can be used at the interfaces between different layers of components inside diverse diets. Moreover, protein-based edible films can be used to transport antibacterial and antioxidant compounds. In order to better protect and confine the food matrix, many young researchers began to examine and produce

### *A Study on Edible Polymer Films for Food Packaging Industry: Current Scenario… DOI: http://dx.doi.org/10.5772/intechopen.107997*

nanostructured antibacterial edible coatings [28]. Protein-based packages can be active because the contact of the packaging with the packed food or the surrounding environment activates it. For illustrate **Figure 2** depicts the various materials and technologies that improve the value of food packages with protein [50]. Having a look at antioxidant and antibacterial compounds, which are most often employed components in the production of an active film or coating. The major goals of the active packages are to delay oxidation (by binding pro-oxidation substances or releasing antioxidants) and to limit pathogen development (organic acids, negatively charged phosphate groups, essential oils, anthocyanins, and chitosan) [51, 52]. Chemical, biochemical, or biological changes on the product's surface activate the release of active substances, ensuring a longer freshness and shelf life. Many significant protein sources may be found in a variety of vegetable and animal sources. Because of the abundance of resources in these fundamental goods, researchers began to extract polypeptides from a wide range of vegetable and animal products or by-products [53, 54]. Many authors prepared protein-based edible films for effective packaging material. Among them, Seung YongCho et al. have prepared oxygen barrier bilayer film pouches from cron zein and soya protein isolate for olive oil packaging for use with instant noodles [55]. Authors Burcu Gokkaya Erdem and Sevim Kaya have prepared edible film by freeze-drying from whey protein isolate and sunflower oil and evaluated functional properties of the films. Authors noticed that oil incorporation into the film matrix has decreased lipid droplet size and increased opacity [56]. Another author Nevena Hromis et al. have investigated possible application of edible pumpkin oil cake film as pouches for flaxseed oil protection. Author concluded that PuOC-based pouches present good protection for flaxseed oil [57]. Similarly, Long-Feng Wang and Jong-Whan Rhim have fabricated and studied the applications of agar/alginate/collagen ternary blend functional food packaging films. Authors noticed that ternary blend films exhibited good antifogging properties as well active packaging materials for highly respiring fresh agricultural products [58]. In

continuation of protein edible films, author Jose Maria Lagaron et al. successfully produced a bio-composite material by melting compounding polyhydroxyalkanoates with a keratin component generated from poultry feathers [59]. Also, Moreira, Maria del Rosario et al. have investigated the antimicrobial property of bioactive packaging material prepared from edible chitosan and casein polymers for carrot, cheese, and salami [60]. Also, Xinyu Liu et al. have conducted the review on Site-selective protein modification with polymers for advanced biomedical applications. Author tried to elaborate current achievements in site-selective protein modification with polymers into five sections: site-selective protein modification; site-selective polymer modification; site-selective in situ generations of polymers from proteins; polymer biosafety; and biomedical applications [61]. Farhan et al. claim that a water extract from the germination of fenugreek seeds may be used to create an edible film of semi-refinedcarrageenan. This edible film can be utilized as an alternative to standard plastic films used in the packaging of chicken flesh for fresh chicken breast [62, 63]. Meanwhile, Furcellaran, a genus of red algae, is one of the most important carrageenan sources. Jamróz et al. combined furcellaean with nanofillers, maghemite nanoparticles, and graphene oxide to produce a film with strong antibacterial activity (for the nanofillers) but not exceptional mechanical qualities [64]. Author prepared *Syzygium cumini* leaves extract doped PVA and PVA/chitosan blend films for food packaging applications. The authors attempted to investigate the physicochemical characteristics of created blend films using XRD, SEM, AFM, FTIR, TGA, and UTM, as well as the films' antimicrobial capabilities. They determined that produced mixes might be used in packaging materials to extend food shelf life (**Figure 2**) [65].

#### **3.3 Lipid-based edible films**

Lipids are organic substances that come from living things including plants, animals, and insects. The presence of phospholipids, phosphatides, mono-, di-, and triglycerides, terpenes, cerebrosides, fatty alcohols, and fatty acids make up the variety of lipid functional groups [66, 67]. Lipids in coatings and edible film offer a variety of benefits, including gloss, the reduction of moisture loss, lower costs, and less complicated packaging [68]. For making lipid-based edible films and coatings more hydrophobic, a very wide variety of chemicals are available. Proteins, polysaccharides, lipids, or any combination of these substances can be used to create edible coatings and films, but the nature of these constituent materials has a significant impact on how well the coatings and films work [69]. Generally, lipids are a possible coating or film-forming substance in this context since the mechanical and barrier properties of edible films are strongly related to the polarity of film components. Lipids are defined as tiny, hydrophobic, naturally occurring compounds. Examples include fats, waxes, sterols, fat-soluble vitamins, and others. Having look at lipids, hydrophobic compounds (lipids) are typically used as a barrier against the transmission of water vapor due to their polar property. Lipid compounds often exhibit mass transfer resistance to vapor and gas transport due to both their hydrophobic nature and structural makeup. To increase the hydrophobicity of edible films, a variety of lipid compounds can be utilized. The waxes of natural origin, vegetable oils, aceto-glycerides, and fatty acids are among the hydrophobic substances that exhibit good potential [70]. Generally, hydrocolloid films are frequently enhanced with lipid components, such as fatty acids and natural waxes, to improve their water barrier qualities [71, 72].

Triglycerides, the main component of fats and oils, are derived from plants and animals, respectively. Although this combination differs physically because fats are solids

*A Study on Edible Polymer Films for Food Packaging Industry: Current Scenario… DOI: http://dx.doi.org/10.5772/intechopen.107997*

and oils are liquids, it is chemically comparable [73]. In 2016, Rodrigues et al. created a palm fruit oil film with preferred water resistance and water vapor barrier for food packaging [74]. In order to improve the quality of food, Vargas et al. (2011) utilized sunflower oil in edible coatings and on pig meat hamburgers. This was done because it was crucial to oxygenate meat and control water vapor in order to avoid an unfavorable reaction [75]. Rice bran oil was tested by Hassani et al. (2012) to increase the shelf life of kiwi fruit. Fruits were mostly preserved based on flavor, color, and firmness [76]. Another level source for the creation of edible films is essential oils. By lowering lipid oxidation, essential oils obtained from diverse plants can increase the shelf-life of food. The water vapor permeability of the films is decreased by adding essential oils [77, 78]. The growth of yeast, bacteria, and mold is inhibited by the use of anise oil, clove oil, and cinnamon oil. The shelf life of dried fish may be extended from 3 to 21 days by adding anise oil (4–6%) to an edible film. This prevents the formation of yeast, bacteria, and mold [79]. One of the main drawbacks is that strong aromas found in essential oils may alter the organoleptic characteristics of food items. Additionally, some essential oils have the propensity to cause allergic reaction issues. As a result, the concentration of essential oils affects their toxicity and organoleptic characteristics [80]. In talk, Aloe veras also considered an appreciable candidate in the food industry being edible material. A. vera gel's primary applications are in the sectors of cosmetics and medicine because of its anti-inflammatory, antiviral, and anticancer properties. It has, however, recently found use as edible films for ice cream, drinks, and other liquids [81–83].

#### **3.4 Synthetic and composite edible polymers**

Diverse edible polymers that combine polysaccharides, proteins, and/or lipids may exist in nature. Synthetic and composite films are prepared by the use of multiple components. The purpose of using numerous components is to gain benefits from their synergistic interactions. This strategy enables one to make use of the unique functional traits of each type of film former. Proteins and carbohydrates, proteins and lipids, carbohydrates and lipids, synthetic polymers, and natural polymers can all be combined to make films [7]. These heterogeneous films were applied in a variety of ways, including consecutive layers, a solution in a common solvent, an emulsion, suspension, or dispersion of the non-miscible ingredients. The barrier qualities of the produced films are influenced by the application technique. Kamper and Fennema have developed emulsion films made of methylcellulose and fatty acids in order to enhance the vapor barrier property of cellulose film [84]. Composite edible polymer films exhibit good barrier qualities because a hydrophilic layer and a hydrophobic layer, which includes lipids, bind together [85]. Composite edible films have been categorized as binary or ternary based on the quantity of biopolymers, as illustrated in **Figure 3**. A binary edible film made of locust bean gum (LBG) and carrageenan is a famous example [87]. Many combinations of carbohydrate-carbohydrate, carbohydrate-protein, and protein–protein are feasible in such systems [88–90]. There is a large body of literature on composite films and coatings made from the combination of two hydrocolloids, but the combination of three hydrocolloids for the creation of edible films or coatings is uncommon. A wide range of polysaccharide-based materials, including tamarind starches, have lately been employed in the production of edible films (Chandra mohan et al. 2016). PVA/Syzygium cumini leaves extract (PSN) and PVA/chitosan/S. cumini leaves extract blend films were prepared as potential candidates in packaging material to extend the shelf life of foodstuffs [65]. In order to increase the mechanical, thermal, and antibacterial characteristics of chitosan

#### **Figure 3.**

*Barrier characteristics of composite edible films and coatings are shown schematically [86].*

films, betel leaf extract (BE) was included into chitosan and chitosan/vanillin (CH/ Vn) mix films [91]. The researchers confirmed that the plant-extract-doped polymer material may be used as a new antibacterial agent in food packaging. Looking into different series, such as chitosan and its nanoparticles, cellulose derivatives, including methyl cellulose and hydroxyl propyl methyl cellulose, pullulan, and natural gums, were prepared and studied as edible packaging material [92–94]. Many natural gums have been extracted from different sources, such as gum ghatti, locust bean gum, and sage seed gum [87, 95, 96]. Furthermore, proteins and polysaccharides have found extensive use in the creation of edible films and coatings. Some of the model proteins include whey protein, sodium caseinate, soya protein isolates, and collagen [97–99].

Suppakul et al. has prepared the soy protein and corn zein bilayer edible film for coating olive oil condiments. Study reported that incorporation of corn zein enhanced the tensile strength, moisture barrier properties, reduced the elongation at break and oxygen barrier properties [89]. Author Gu and Wang et al. has prepared the zein/ gliadin binary film. Study reported that improved flexibility elongation at break, decreased brittleness and gliadin has significant impact on moisture content and solubility [100]. In another work, Song et al. created binary films out of scarcely bran protein and gelatin [101]. Authors concluded prepared films exhibited excellent film forming properties and composite film was complexed with grapefruit seed extract to enhance the antibacterial and antioxidant properties. The result of the study showed, when compared to the control preparation, the count of escherichia coli O157:H7 and listeria monocytogenes was dramatically reduced (without grapefruit seed extract). Similarly, salicylic acid and acetyl salicylic acid were utilized as fillers in the zein films, and their structure and mechanical characteristics were investigated [102]. Thakur et al. has formulated the bilayer film using starch combined with ι-carrageenan. Steric acid and glycerol were used as plasticizers [90]. Furthermore, Antoniou et al. has prepared binary film using chitosan nanoparticles and tara gum and characterized for thermomechanical, antimicrobial and barrier properties [103]. Authors confirmed that complexation process improved the tensile strength and elongation at break. In addition, Mei et al. has formulated the water chestnut starch and chitosan based bi-layered films [104]. Author concluded that addition of fruit extract has influence on the pH and moisture content of the film and demonstrated better mechanical properties.

#### *A Study on Edible Polymer Films for Food Packaging Industry: Current Scenario… DOI: http://dx.doi.org/10.5772/intechopen.107997*

Martins et al. has fabricated the Locust bean gum combined with κ-carrageenan edible films. The study revealed that the two biopolymers had a high synergy [87].

In another research work, edible films made of chitosan and fish gelatin were irradiated with an electron beam. Quercetin was trapped in the composite film due to a decreased release profile caused by irradiation [105]. The study of gelatin/chitosan composite edible films filled with antimicrobial extract (ethanolic extracts of cinnamon, rosemary, guarana and boldo-do-chile) shown antimicrobial and antioxidant properties [106]. A number of research have concentrated on creating ternary blend films. Mention few, Jia et al. has ternary edible films using Konjac glucomannan, chitosan and soy protein isolate using glycerol as the plasticizer [99]. Wang et al. has studied the whey protein isolate, gelatin and alginate ternary edible films and demonstrated the mechanical properties and barrier properties, such as water vapor permeability and oxygen permeability [107]. A ternary edible film made of konjac glucomannan, chitosan, and nisin was created, and its physical, mechanical, barrier, optical, structural, and antibacterial characteristics were investigated [108]. In the study, it was observed that ternary blend films exhibited high tensile strength, optimum transparency, and strong antimicrobial efficacy against S. aureus, L. monocytogenes, and B. cereus. Wang and Rhim formulated the ternary blend films from agar, alginate, and collagen. Also, blended films were successfully functionalized with silver nanoparticles and grapefruit seed extract as antimicrobial agents [58]. Polycaprolactone, methylcellulose, and polycaprolactone were combined with several antimicrobial substances, including organic acids, rosmarinic acid, an Asian essential oil blend, and an Italian essential oil combo, to create quadruple edible films. The prepared antimicrobial films could significantly resist the growth of both *S. aureus* and *E. coli* [109].

#### **4. Functionality and composition**

The majority of foods are recognized to be vulnerable to mechanical harm, physiological degradation, water loss, and rot when in storage. As a result of water loss, plants become less turgid, which accelerates the loss of nutrients and organoleptic qualities and is a key factor in degradation. Spoilage might be reduced by using edible coatings and cold storage [110]. Edible films are often used to carry active compounds, such as antioxidants, tastes, fortified nutrients, colorants, antibacterial agents, or spices, while also acting as a barrier against gases or vapor. Controlling mass transfers, providing mechanical protection, and enhancing sensory perception are the three most crucial functions of an edible film or coating. Controlling mass transfers includes keeping food from drying out, managing gas microenvironments around food, and limiting component and additive migration in food systems. Edible films have two main functions: to maintain the food's mechanical integrity or handling features and to act as a selective barrier to different gases, moisture, aromas, and lipids. Edible films and coatings can improve the look of coated food and govern adhesion, cohesion, and durability in addition to their barrier capabilities. Edible films act as a conduit for interactions between the environment, the product, and the packaging. Typically, these interactions involve a range of physical, chemical, and biological activities that change the natural environment in which the food is packed, improving the product's sustainability, safety, quality, and shelf life [111]. Perhaps, by modifying and controlling the internal environment of individual items, edible coatings on fresh foods can offer an alternative to modified atmosphere storage by decreasing quality changes and quantity losses. Even while oxygen entry may lower food quality due to oxidation of the fragrance components in

the food, altering internal atmosphere by the application of edible coatings might exacerbate diseases linked to excessive carbon dioxide or low oxygen concentration [112]. For fresh items, edible film with higher water vapor permeability is also preferred, yet exceptionally high-water vapor permeability is also not preferred since it may cause fruit to lose too much moisture during storage. To maintain the integrity of the package throughout distribution, an edible film must have sufficient mechanical strength. Acceptance of finished items is largely determined by the sensory qualities of an edible coating or film. In conclusion, the most beneficial characteristic of edible films and coatings are their edibility and inherent biodegradability [113, 114].

#### **4.1 Physical and mechanical protection**

In general, edible films and coatings shield packed or coated foods from physical harm brought on by mechanical forces including pressure, vibration, and collision. The tensile strength of edible films should typically be lower than that of conventional plastic films, however, their elongation at break varies greatly. The majority of edible and coated films are extremely moisture-sensitive [115]. However, their physical strength decreases at greater relative humidity levels because absorbed moisture works as a plasticizer. Consider the importance of temperature in influencing the physical and mechanical qualities [116–118]. When temperatures rise over the glass transition point, materials' physical strength is drastically reduced.

#### **4.2 Functions of migration, permeation, and barriers**

Mass transfer events, such as moisture absorption, oil absorption, oxygen invasion, taste loss, unwanted odor absorption, and migration of packing materials into food in general deteriorate the quality of foodstuffs [119, 120]. Deterioration mechanism involves penetration of oxygen into foods, which causes the oxidation of food ingredients; inks, solvents, and monomeric additives in packaging materials might migrate into foods. Edible films and coatings prevent the migration phenomenon and quality deterioration [114, 116]. It is best to use stand-alone edible films to measure the transmission rates of certain migrants in order to define the barrier qualities of edible films and coatings. The majority of study has focused on the oil resistance, taste permeability, oxygen permeability, carbon dioxide permeability, and water vapor permeability of edible films.

When it comes to handling convenience, edible films and coatings provide a number of advantages. The reinforced surface strength of delicate items facilitates handling easier. Fruits and vegetables with coatings are far more resistant to bruising and tissue damage brought on by impact and vibration. Edible films and coatings serve a number of extremely important purposes, including quality maintenance and improvement [121]. They may prevent the microbiological degradation of food goods as well as surface dehydration, moisture absorption, ingredient oxidation, fragrance loss, frying oil absorption, and ingredient oxidation. In view of physical and chemical quality, edible films and coatings improve visual quality, surface smoothness, taste conveyance, edible color printing, and other marketing-related quality criteria [121].

#### **4.3 Extension of shelf life and improvement of safety**

Extension of shelf life and increased safety are closely connected to the improvement and maintenance of quality. Food items with higher protective functions have

*A Study on Edible Polymer Films for Food Packaging Industry: Current Scenario… DOI: http://dx.doi.org/10.5772/intechopen.107997*

longer shelf lives and are less likely to become contaminated by foreign objects [120–123]. Due to the recent significant rise in the market for fresh produce and minimally processed goods, it is necessary to keep these items safe and increase their shelf life [124, 125]. Improved systematic methods are required to preserve safety and shelf life due to the enormous size of modern food manufacturing, distribution networks, food service franchises, and fast food restaurants.

#### **4.4 Transporters for active ingredients and controlled release**

For food components, medicines, nutraceuticals, and agrochemicals, edible films and coatings can be used in the form of hard capsules, soft gel capsules, microcapsules, soluble strips, flexible pouches, coatings on hard particles, among other forms [120, 126]. Many food-grade preservatives and natural antimicrobials have been combined into edible film and coating materials. They act as successful examples of how to efficiently inactivate spoilage or pathogenic bacteria on the surface of susceptible food items [127, 128]. To prevent the autooxidation of high-fat food items, natural antioxidants have also been integrated into edible film and coating materials [129]. The capacity for regulated release is the most crucial factor to consider when evaluating the efficacy of various applications [123]. One needs to concentrate on this because various release rates, such as instantaneous release, gradual release, a particular release rate, or non-migration of active chemicals, are necessary depending on the application. To create controlled-release systems, a variety of different active ingredients can be added to film-forming polymers. Antimicrobials, antioxidants, bioactive nutraceuticals, medicines, flavors, inks, fertilizers, insecticides, insect repellents, and medical/biotechnology diagnostic agents are good examples of active chemicals needing certain migration rates. To inactivate contaminated spoilage or pathogenic bacteria, several natural phenolic compounds have been added to edible coating materials and applied to microbiologically vulnerable foods [130–134].

#### **5. Fabrication of edible films**

Understanding the chemical makeup and structural details of additives, biopolymers, and other materials that create films is crucial for configuring them for particular uses [122, 135]. It is crucial to use a solvent that is both water and ethanol soluble when wet casting or combining active agents. There two types of film-making techniques are dry and wet [116]. In dry method of making edible films does not require liquid solvents, such as water or alcohol. Dry techniques include molten casting, extrusion, and heat pressing. Generally, heat is provided to the film-forming materials during the dry process to raise the temperature over the melting point of the film forming ingredients, causing them to flow. During film preparation, it is important to note down the impact of plasticizers and other additives on the thermoplasticity of film-forming materials must be determined. Plasticizers lower the glass transition temperature.

The wet technique disperses film-forming ingredients in solvents before drying to remove the solvent and produce a film structure. One of the most significant components of the wet process is solvent selection. Only water, ethanol, and their combinations are suitable as solvents since the film-forming solution needs to be eatable and biodegradable [136]. To create film-forming solutions, all the components of film-forming materials should be dissolved or uniformly distributed in the solvents. By using a sprayer, spreader, or dipping roller, the film-forming solution should be


#### *Advances in Rheology of Materials*

**Table 2.** *Several edible films prepared using polysaccharide as edible matrix and industrial waste.*

#### *A Study on Edible Polymer Films for Food Packaging Industry: Current Scenario… DOI: http://dx.doi.org/10.5772/intechopen.107997*

applied to flat surfaces. Once cured, the solvent should be removed to create a film structure. The development of uniform edible film and coating systems including active additives depends heavily on the components' compatibility with the solvent. To create film-forming solutions, all constituents, including active additives, biopolymers, and plasticizers, should be uniformly dissolved in the solvent. The coating procedure is also impacted by the film-forming solution's viscosity. A reduced viscosity speeds up the film-forming solution's separation from the flat surface, which results in an uneven coating on the surface and the coating solution trickling down to the floor. To decrease this coating phase separation, higher viscosity of the film-forming fluid is preferred, unless doing so results in an unacceptably thick coating thickness. The likelihood of a film layer developing on the flat surface during the high-speed coating process increases if the film-forming solution has lower surface tension and a greater viscosity. However, coated films' lower surface energies after drying make it more difficult to remove the film off flat surfaces. **Table 2** summarizes the different edible films prepared using polysaccharide as edible matrix and industrial waste.

System that is commercially viable includes new processing technologies, such as extrusion, roll orientation, conveyor drying, bath coating, pan coating, or other procedures, which would be needed to produce edible films and coatings. These new manufacturing technologies should be economically viable and compatible with the methods now used to produce packaging films and food coatings. Therefore, composition of film-forming materials should be carefully tuned, and the film-forming processes must be updated correspondingly, to fulfill the feasibility of new production systems [1].

### **6. Characterization and performance analysis**

The appropriate use of edible packaging films largely depends on their mechanical and barrier properties. Therefore, it is critical to establish precise approaches for assessing film performances, particularly for the measurement of permeability values that can be effectively applied to forecast the self-life of products. The instruments employed to determine permeability are standardized ones and available for water vapor and permanent gas transfers. They were developed for use with synthetic and plastic packaging films. The rate of water vapor transmission per unit area of flat material with a unit thickness and per unit vapor pressure differential between two particular surfaces, under predetermined temperature and humidity conditions, is known as water vapor permeability (WVP). Based on infrared sensors, such as the Permatran-W series offered by Mocon, or WVP tester L80–4000 series of Dr. Lissy which works on the principle of coulombic or spectrophotometer method several methodologies have been refined by Holland and Santangelo [156]. In contrast to hydrophilic polymers, these approaches are particularly suited for high-barrier efficiency polymers, such as plastics or wax-based edible films [157]. The "cup method," which is based on the gravimetric methodology, is the approach most frequently utilized by those who work on edible packaging.

For the purposes of applying edible coatings on fruits and vegetables, it was frequently investigated how permeable they were to gases, especially oxygen and carbon dioxide. The ASTM D1434 and ISO 2556 standards' manometric and volumetric methodologies were not used for edible films [158, 159]. In this regard, Oxtran device was the best one that could be used to measure gas permeability through edible films. As a result, plastic research on the gas permeability of edible packaging

was conducted using the gas chromatographic method created by Karel et al. and Lieberman et al. for collagen films [160, 161]. A gas chromatographic technique has recently been improved by Debeaufort and Voilley to quantify permanent gases, water, and organic vapor [162]. If the mechanical qualities of an edible film or coating do not allow for the maintenance of the film togetherness during usage, packing, and transport procedures, even one with excellent barrier properties may not be effective. Therefore, it is necessary to ascertain the mechanical strength and injury of edible films. To analyze the tensile strength, young's modulus, elongation at break, and elasticity of edible films, instruments, such as a universal testing machine, dynamic mechanical thermal analyzer, and texturometer, are frequently utilized [163]. Numerous other aspects of films are frequently researched, particularly in order to comprehend their mechanical and barrier properties, such as thickness, degradability, solubility, opacity, color, antimicrobial activity, and thermal stability.
