Abstract: Background. As a food, groundnut is one of the most concentrated products, since it is very high in calories due to its high fat and protein content. One gram of groundnut supplies 6.03 kcal (25.2 kJ) compared with 4 kcal (16.7 kJ) for pure cane sugar, 3.6 kcal (15.1 kJ) for polished rice, 3.5 kcal (14.6 kJ) for maize flour and 2.7 kcal (11.3 kJ). Groundnut flour is used as food and 2.7 kcal (11.3 kJ). Groundnut flour is used as food in soup or stew, sauces, confectionaries, puddings, bakery products and in various other ways for human consumption. These uses of groundnut necessitate the determination of the general composition of groundnut.
Material and methods. About 1.0 kg dried seeds of groundnut was involved in the analysis of the sample. It was divided into three parts for the dry, dry cooked and dry roasted samples. Defatted groundnut seeds were used using standard analytical method in which chloroform/methanol (2:1 v/v) was used as extraction solvent. Ion exchange chromatography method was used in the analysis of the amino acid composition using the Technicon Sequential Multisample (TSM) Amino Acid Analyser. Various methods were used to determine the quality parameters of the protein. Other parameters were the predicted protein efficiency ratio (P-PER), essential amino acid index (EAAI) and the isoelectric point (pI). The statistical analysis was also carried out.
Results. Total amino acid was as follows: (g/100 g crude protein, cp): 83.5 (raw seeds, Rs), 85.9 (cooked seeds, Cs) and 66.8 (roasted seeds, Rt.s) with corresponding essential amino acids as: 39.4 or 47.2% (Rs), 38.3 or 44.6% (Cs) and 30.0 or 44.9% (Rt.s). Predicted protein efficiency ratios were 2.55 (Rs), 3.00 (Cs) and 2.31 (Rt.s) and essential amino acid index of 1.18 (Rs), 1.08 (Cs) and 0.83 (Rt.s). Cooking enhanced the amino acid levels of Asp, Ser, Glu, Pro, Arg, Ala, Cys, Val, Leu and Phe. The following essential amino acids were reduced by both cooking and roasting: Lys (15.9-27.6%), His (4.23-
-16.5%), Thr (40.1-60.6%), Met (38.0-63.4%) and Ile (13.3-31.8%). All the parameters between Rs/Cs and most of the parameters between Rs/Rt.s were significantly different at r=0.05.