**2. Peanut proteins**

*Grain and Seed Proteins Functionality*

content, size, shape, and disease resistance [11].

diabetes, cancer, gallstone and alzheimer's [12, 13].

Peanut has now become one of the major global oil-seed crops covering approxi-

mately 26 million ha land area in about 120 countries [4–6]. According to FAO, world production of groundnut is above 45 million tons, averaging about 1.8 t/ha. Significant level of annual peanut production has been recorded in India amounting to approximately seven million tons [7]. China leads in production of peanuts, with a share of about 41% of overall world production, whereas India has 14% share and the United States has (7%) [8]. *Arachis hypogaea* has been divided into two subspecies *A. hypogaea* ssp. *hypogaea* and *A. hypogaea* ssp. *fastigiata* [9]. Morphological variations in branching and flowering patterns, pod and seed traits are used to characterize different botanical varieties [10]. The varieties are further distinguishable into a number of market types or cultivars like Virginia (large seeded), Runner (small seeded), Peruvian runner, Valencia and Spanish type. Some market types or cultivars are more preferred for some particular uses due to differences in flavor, oil

Peanut is accepted as a potential source of food grade protein and an energy dense food. The seed typically contains 36% to 54% oil, 16% to 36% protein, and 10% to 20% carbohydrates as well as high amounts of macro minerals, trace elements, vitamins riboflavin, niacin, folic acid, fiber and vitamin E, resveratrol, phytosterols. It is also known as poor man's nut and being seen as potential functional food. A 100 g of peanut kernels provide 567 kcal of energy and 8.5 g of dietary fiber [12]. Consumption of peanuts can reduce risk of inflammation and diseases like

Peanuts are consumed all over the world in a wide variety of forms such as raw, boiled or roasted, and are widely used to prepare a variety of packaged foods (peanut butter, candies, confections, and snack products) in the United States. Peanuts and peanut butter contain monounsaturated fatty acids besides plant proteins, minerals like magnesium, potassium, fiber, arginine and various bioactive components. The by-product of the oil extraction is a meal that is also high in proteins, dietary fiber, antioxidants, vitamins, and minerals, and can be utilized as animal feed or processed further for human consumption. The defatted protein flour after oil extraction in peanuts, has immense uses and has been exploited in meat-like products that can be used to formulate cholesterolfree vegetarian alternatives [14]. Peanut flour is used in composite flours with non-wheat cereals to improve the nutritional value of bread [12]. Peanut bars, peanut milk and fermented peanut are also different forms of consumption. Protein energy malnutrition in third world developing countries is a problem due to dependence on animal proteins which are expensive and thus, affordable plant proteins with its additional benefits are being exploited such as peanut proteins, which can be used to combat protein-energy malnutrition. Partially defatted peanut flour, is a protein-rich, inexpensive and underutilized product that offers the same health and dietary benefits of peanut with less fat and can be utilized for making value added products to eradicate malnutrition among children [15]. Peanut proteins play an important role in many food products because of their properties such as nutritional value, contribution to food texture, solubility etc., among others. Huge tons of by-products obtained from peanut industries can be utilized to generate a reasonably high quantity of protein, that could be further used in a variety of food formulations due to its properties such as water and oil absorption, gel formation, foaming, emulsification etc. Functional properties depend upon extraction procedure and use of

Thus, the present chapter focuses on the peanut seed storage proteins composition, nutritional value, bioactive components, functional properties, its usage and

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adequate modification methods [16].

methods to reduce allergenicity.

Seed storage proteins are present as one or more groups of proteins in high amounts in seeds to provide a store of amino acids for use during germination and seed growth. The peanut seed contains 32 different proteins comprised of albumins and globulins. The seed storage proteins are mainly composed of arachin (legumin), conarachin (vicilin) - I, II fractions [17]. Many papers have highlighted the composition of seed storage proteins (SSPs) using one dimensional and two dimensional PAGE [18–21]. The different fractions of seed proteins by SDS PAGE in groundnut cultivars is shown in **Figure 1**. SSPs in peanut are composed of families of 2S, 7S, and 11S proteins that can be subdivided in homology groups. 11S proteins are more diverse than 2S and 7S proteins in peanut seeds, but 2S and 11S subgroups are very similar in the A and B genomes of *Arachis* [20].

However, peanut proteins is also a source of severe IgE-mediated allergies in some individuals. Due to peanut being recognized as one of the potent allergens, the immunological protein names with prefix *Ara* with different numbers have also been designated from Ara h 1 to Ara h 17.
