**3. Physicochemical properties of garden cress seed oil**

Physicochemical parameters provide important information regarding storage, stability, and quality of the product. The physicochemical properties of garden cress seed oil (GCSO) extracted by the different methods are presented in **Table 2** [21]. Extracted oil by solvent extracted, supercritical CO<sup>2</sup> , and cold expression were 21.54, 18.15, and 12.60%, respectively. The Soxhlet method yields the maximum oil content (21.54%). Oil yield of GCS is low when compared to the other oil seeds of Cruciferae family like mustard (25–40%), rapeseed (40–45%),


Each value is a mean ± SD of three determinations. Values within the same row with different alphabetical superscripts are significantly different at P < 0.05.

1 nDt is the unit of refractive index (nD) for light with a wavelength equal to 589.3 nm at temperature, t = 24°C.

2 The direct pycnometer determination at 33°C.

3 Viscosity determined at 25°C MPa s−1. Data compiled from: Diwakar et al. [21].

**Table 2.** Physicochemical properties of garden cress seeds extracted by various extraction methods.

and camelina or false flax (40–45%) [22]. The pungency of GCSO and mustard oil are similar, while the content is lower. The physicochemical properties of GCSO as summarized in **Table 2** establish the potential of garden cress for the development of novel products with several functional properties.

#### **3.1. Physical properties of garden cress seed oil**

Physical properties like color, odor, viscosity, specific gravity, and refractive index are important during the development of food products, because these properties may affect the different quality parameters of the developed products.

### *3.1.1. Color*

Color of any oil determines the attraction of consumer and acceptability of the product. Garden cress oil color is dirty yellow due to the presence of chlorophyll and carotenoids pigments, which are unintentionally co-extracted during the oil extraction [23].

#### *3.1.2. Viscosity*

Viscosity of the GCSO ranges from 53.8 to 64.3 (**Table 2**). The cold-pressed GCO was more viscous than the oil extracted by the other two methods. Increasing extraction temperature up to a certain value increased viscosity, but at higher extraction temperatures viscosity decreased. The reduction of gum viscosity with temperature might be the result of irreversible change in molecular conformation [24]. It was concluded that high pH, low water, seed ratio, and mild extraction temperatures will give a high viscosity for *L. sativum* extract. It decides the flow behavior of the products and is considered much during the formulation of any liquid or semisolid products.

#### *3.1.3. Refractive index*

High refractive index value (1.47 ± 0.03) is the indication of substantial unsaturation and the presence of unusual components such as hydroxyl groups in GCSO [25]. It also provides useful information about the purity of oils. The refractive index of GCO is within the range of edible oils (**Table 2**); therefore, it can be a good fortifying agent for the product development.

#### *3.1.4. Specific gravity*

Specific gravity of garden cress seeds (0.91) resembles with the specific gravity value of milk. This suggests that drinks can easily be fortified with processed garden cress seeds powder and thus several health drinks can be formulated by incorporating GCS [13].

#### **3.2. Chemical properties of garden cress seed oil**

Chemical properties help in determining the stability of the GCSO and the developed blended products. It also helps in determining the shelf life of the food products.

#### *3.2.1. Free fatty acids and peroxide value*

The free fatty acids (FFA) and peroxide value (PV) of the cold-pressed GCSO is lowest compared to the oils extracted by solvent and supercritical CO<sup>2</sup> extraction (**Table 2**). The FFA content of supercritical CO2 extracted GCSO is higher than the oil extracted by cold pressed and Soxhlet extraction. The acid value of oils depends upon the oil extraction methods apply. Lower the FFA, higher the stability of oil at room temperature (25 ± 2°C). The content of FFA of GCSO (**Table 2**) is in limit with the specifications of vegetable oils (1–7% of oleic acid). The high PV in Soxhlet extracted oil could be due to the exposure of the oil to high temperature (60–80°C) during extraction. The low PV of cold-pressed GCSO indicates that it is less prone to oxidative rancidity at room temperature.

#### *3.2.2. Iodine value*

and camelina or false flax (40–45%) [22]. The pungency of GCSO and mustard oil are similar, while the content is lower. The physicochemical properties of GCSO as summarized in **Table 2** establish the potential of garden cress for the development of novel products with several

Physical properties like color, odor, viscosity, specific gravity, and refractive index are important during the development of food products, because these properties may affect the differ-

Color of any oil determines the attraction of consumer and acceptability of the product. Garden cress oil color is dirty yellow due to the presence of chlorophyll and carotenoids pig-

Viscosity of the GCSO ranges from 53.8 to 64.3 (**Table 2**). The cold-pressed GCO was more viscous than the oil extracted by the other two methods. Increasing extraction temperature up to a certain value increased viscosity, but at higher extraction temperatures viscosity decreased. The reduction of gum viscosity with temperature might be the result of irreversible change in molecular conformation [24]. It was concluded that high pH, low water, seed ratio, and mild extraction temperatures will give a high viscosity for *L. sativum* extract. It decides the flow behavior of the products and is considered much during the formulation of any liquid

High refractive index value (1.47 ± 0.03) is the indication of substantial unsaturation and the presence of unusual components such as hydroxyl groups in GCSO [25]. It also provides useful information about the purity of oils. The refractive index of GCO is within the range of edible oils (**Table 2**); therefore, it can be a good fortifying agent for the product

Specific gravity of garden cress seeds (0.91) resembles with the specific gravity value of milk. This suggests that drinks can easily be fortified with processed garden cress seeds powder

Chemical properties help in determining the stability of the GCSO and the developed blended

and thus several health drinks can be formulated by incorporating GCS [13].

products. It also helps in determining the shelf life of the food products.

**3.2. Chemical properties of garden cress seed oil**

ments, which are unintentionally co-extracted during the oil extraction [23].

functional properties.

284 Advances in Seed Biology

*3.1.1. Color*

*3.1.2. Viscosity*

or semisolid products.

*3.1.3. Refractive index*

development.

*3.1.4. Specific gravity*

**3.1. Physical properties of garden cress seed oil**

ent quality parameters of the developed products.

The unsaturation of an oil or fat is measured by the iodine value (IV). IV depends on the unsaturated fatty acids present in the oil or fat. The IV of oil extracted by cold-pressed and supercritical fluid extracted of GCSO was relatively lower than solvent extracted (**Table 2**). The IV of the oil is affected due to the presence of many long chain unsaturated components like olefins, including carotenoids and squalenes [26]. The solvent-extracted oil contained a significantly higher amount of total carotenoids than the cold-pressed oil. Thus, the higher carotenoid content might be responsible for a high IV in solvent-extracted GCSO.

#### *3.2.3. Saponification value*

SAP value is the number of milligrams of potassium hydroxide required to saponify 1 g of fat or oil. It measures the average molecular weight (or chain length) of all the fatty acids present. The range of SAP value of GCSO is 174.00–182.23, indicating that the oil contained high molecular fatty acids (**Table 2**). The SAP value of GCSO is lower (178.36) than the palm oil (196–205), olive oil (188–196), sunflower oil (186–196), soybean oil (188–195), and safflower oil (186–198) [27]. Thus, the saponification value is appropriate to form or supplement in to other product.

#### *3.2.4. Unsaponifiable matter*

Unsaponifiable matter (USM) shows the pigments, chlorophyll, and other heterocyclic compounds present in the oil. The USM content in GCSO extracted by different method varied from 1.16 to 1.65 g/100 g (**Table 2**). The USM content was higher in GCSO than in sesame (1.2%), white melon (1.1%), corn (0.92%), cotton (0.52), palm (0.34%), peanut (0.33), palm kernel (0.22), and coco kernel (0.09) oil [28]. The presence of lignan (29.4%), crude fiber (16.5%), protein (24.3%), and minerals (5.4%) in GC seeds the USM contents was high [29].

#### **3.3. Functional properties and other health benefits of garden cress seeds**

#### *3.3.1. As antioxidants: free radical scavenging activity*

The antioxidant properties depend on the phenolic compounds present in garden cress seeds. The main phenolic compounds present in GCS extracts are tocopherols. Tocopherols act as biological scavengers of free radicals that inhibit oil oxidation. Tocopherols also help in preventing diseases, besides possessing an important nutritional function for human beings as a source of vitamin E [30, 31]. High amounts of tocopherols present in GCS can be responsible for the stabilization of fats and oils to prevent the oxidative deterioration and for its applications in dietary, pharmaceutical, or biomedical products [32]. Total tocopherol contents in GCSO is 139.73 ± 0.91 mg/100 g and δ tocopherol was the most abundant in the seed oil of GC. Vitamin E (tocopherol) is an important antioxidant, which protects vitamin A and essential fatty acids from oxidation and prevents breakdown of body tissues. Garden cress seeds possess maximum DPPH inhibition activity at concentrations of 100, 150, and 200 μg of methanolic extracts as reported during DPPH radical scavenging assay. These values are comparable with the standard free radical scavenger BHA at concentration 10, 50, and 100 μg [33]. Due to high free radical scavenging potential of GCS, its fortification to prepare balanced diet may help in incorporating and exploiting its rich nutritional as well as medicinal value to the developed food.

#### *3.3.2. As galactogogue and emmenagogue: for inducing milk secretion and menstruation*

GCS can be used as a supplement for proper regulation of the menstrual cycle, because it has mild oestrogenic properties. It shows emmenagogue like herbal properties, which gave it an important place in Vedic era. Emmenagogues are herbs, which have the ability to provoke menstruation. They stimulate blood flow in the pelvic area and uterus and thus induce menstruation. GCS is used as emmenagogue in order to stimulate menstrual flow when menstruation is absent either due to pregnancy to cause an abortion or prevent pregnancy or for reasons other than pregnancy, such as hormonal disorders or conditions like oligomenorrhea. Similarly, consumption of GCS after birth of baby increases milk production and secretion in lactating mothers. Because of its high iron and protein content, it is often given post-partum as effective galactogogue to induce lactation in nursing mothers to meet the nutritional requirement of their children. Galactogogues promote lactation in humans and other animals. They exert their pharmacological effects through interactions with dopamine receptors, resulting in increased prolactin levels and thereby augmenting milk production [34].

#### *3.3.3. As gastrointestinal tract cleansing agent*

Garden cress helps in cleansing gastro intestinal tract and stimulates appetites. The testa of these seeds contain mucilage which can be used during constipation as a laxative and a purgative. The paste of GCS and honey can be taken internally to treat amoebic dysentery. The irritation of the intestines in dysentery and diarrhea effectively reduces by the use of mucilage of the germinating seeds of GCS. Crushed GCS taken with hot water is beneficial to treat colic disease especially in infants. The plant is also used in treating bleeding piles.

#### *3.3.4. As haematic agent*

The GCS is the rich source of iron, which is easily absorbed in intestine and helps to increase the hemoglobin level in blood. The bioavailability of iron content in GCS beneficial for anemia when taken daily. Vitamin C taking half an hour after consumption of these seeds enhances the iron absorption. L-ascorbic acid facilitates iron absorption by forming a chelate with ferric iron at acid pH converting them to ferrous state that remains soluble at the alkaline pH of the duodenum which gets easily absorbed [35, 36].
