COMPARATIVE STUDY ON THE PHYSICO-CHEMICAL PROPERTIES OF PIGEON PEA (Cajanus cajan) FLOUR AND PROTEIN ISOLATE

Pigeon Pea seeds (Cajanus cajan) were produced into three different flour samples; full fat, defatted and protein isolate. They were subjected to proximate analysis and determination of some functional properties. Proximate composition was carried out on moisture content, protein content, fat content, carbohydrate, ash content and crude fibre content. The proximate analysis (%) shoed that protein isolate had the lowest moisture content 0f 6.63 ± 0.025 compared to full fat and defatted flour having 6.85 ± 0.012 and 6.76 ± 0.016 respectively. Also, the result showed that protein isolate had the highest protein content of 90.65 ± 0.005% than that of full fat, and defatted flour having 24.02 ± 0.016%, and 26.30 ± 0.016%. The fat, carbohydrate, ash and fibre content (% for full fat, defatted and protein isolate were (2.017 ± 0.062, 0.113 ± 0.0094, 0.00 ± 0.00), (62.23 ± 0.029, 62.22 ± 0.016, 0.2 ± 0.016) (3.14 ± 0.016, 3.05 ± 0.033, 2.52 ± 0.016) and (1.24 ± 0.016, 1.56 ± 0.015, 0.00 ± 0.00) respectively. Generally, the result of the protein isolate showed no value for fibre and fat content and very low value for carbohydrate. The presence of fibre in full fat flour and defatted flour helps in the functioning of gastro intestinal tract and aid in digestion of food. Finally, the proximate composition of three samples showed that they are good sources of protein, fat and carbohydrate with functional properties that are favourable to human consumption and useful application in food systems. © 2012 Universal Research Publications. All rights reserved INTRODUCTION Pigeon pea (Cajanus cajan) is among the dry leguminous cultivated for food in Nigeria. It is also an important food legume in African and south – East Asia (Muhammed et al; 1979). Leguminous seeds are important source of proteins, energy and other nutrients in the diets of large population groups around the world, forming and excellent source of lysine, methionine and tryptophan and other water – soluble vitamins (riboflavin, niacin and folacin) and of the minerals phosphonrus, iron and magnesium. (Ramcharan and Walker, 1985). These seeds, therefore, have high food value and are second to cereals as a source of human and animal food leguminous seeds are especially significant in that they provide supplementary proteins to diet based on cereal grains such as rice, and starchy food e.g plantain and cassava (Doughty and Walker, 1982). Green pods of legumes such as winged bean and lima bean and some varieties of pigeon pea are used as vegetables (Nandanie, 2003). The high content of varieties of legumes make them important sources of protein in the diets of population groups of many tropical countries (Kon, 1979, Ekpeyoung and Borchers, 1980). The common legumes cultivated in Nigeria include soybean, bambara groundnuts, Africa yam bean and pigeon pea. A mature grain legume seed has three major components; the seed coat (testa or hull), the cotyledons and the embryo axis (Okaka, 1997). Pigeon pea seeds have a growing season of 6 to 9 months and are either harvested dry and used mainly in dahl soap, or harvested earlier and eaten as a green vegetable. It is used as a food crop (dried peas, flour or green vegetable peas) and also as forage / cover crop. In combination with cereals, pigeon pea known as “Fiofio” in Eastern part of Nigeria, make a well balanced human food. It is an annual crop reaching 3 to 12ft (1 to 4 meters) in height. The leaves have three leaflets that are green and pubescent above and silvery grayish green with silvery grayish green with longer hairs on the underside. The flowers are yellow with red to reddish – brown lines or a red outside. Pigeon pea seed-lings Available online at http://www.urpjournals.com International Journal of Agricultural and Food Science Universal Research Publications. All rights reserved