Comparison of the Amino Acid and Protein Content between Peanut Meal and Fermented Peanut Meal

Abstract

Peanut meal (PNM) is considered an inferior protein supplement and used as an inexpensive source of protein. In order to improve the nutritional qualities of PNM, it was fermented by Bacillus subtilis AS1. 260. The amino acids and protein concentration were investigated before and after fermentation by Bacillus subtilis AS1. 260. SDS-PAGE electrophoresis was used to measure proteins molecular weight between PNM and fermented peanut meal (FPNM). The results shows that under the optimum conditions (water volume 50 ml, fermentation 40 h, autoclave period 45 min, (NH4)2SO4 quantity 2.0 g), the No. 9 PFNM had the highest protein content of 55.93 %. PNM fermented by Bacillus subtilis AS1.260 can result in polypeptides of less than 24 kDa. The essential amino acids (EAA) Tyr, Val, Met, Ile, Leu and Lys increased significantly from 1.44, 1.46, 0.09, 1.22, 2.43, 0.90 to 1.51, 2.19, 0.58, 1.78, 2.84, 2.54, respectively (p<0.05). The total amino acids (AA) also increased significantly from 36.39 to 42.40 % (p<0.05). To sum up, fermentation of PNM by Bacillus subtilis AS1.260 can increased significantly the levels of protein, essential amino acids, and amino acids, furthermore, can hydrolyzes the PNM proteins into smaller peptides, which indicates that the fermented PNM can be used as a promising inexpensive source of protein supplement.