Amino acid profile and protein quality of starter cultures fermented African Yam bean (Sphenostylis sternocarp) seed condiment

Abstract

African yam bean seeds condiment is an unpopular nutritive local food seasoning compared to Iru and is mostly produced by natural fermentation. Production with a defined starter culture will give a novel functional condiment with enhanced nutritive values, especially amino acids, to prevent hidden hunger, shorten the fermentation time, and improve product uniformity. The effect of different monoculture bacterial starters and natural fermentation on the amino acids profile of condiments produced from African yam bean seeds was investigated. The result revealed a total of 18 amino acids with glutamic and aspartic acids as the most abundant amino acids in all the samples portions, with a range of values of 9.79-11.44 g/100 g protein and 9.20 -10.67 g/100 g protein respectively. The inoculated samples were rich in all the amino acids quality than un-inoculated. The total amino acid content of the samples was significantly different (p ≤ 0.05). Bacillus amyloliquefacien starter fermented sample had the highest total amino acid value of 95.80 g/100 g protein while Bacillus subtilis fermented and un-inoculated seed portion samples had a total amino acid value of 86.81 g/100g and 74.04 g/100 g protein respectively. The essential amino acids (EAA10) were significantly different (p ≤ 0.05) and were in the range of 35.75-46.32 g/100 g protein with leucine, arginine, lysine, valine, isoleucine and phenylalanine the most abundant in inoculated and un-inoculated samples portions and were more concentrated in inoculated samples. Non-essential amino acids were slightly higher (38.29 - 49.47 g/100 g protein) than the total essential amino acids. The total acidic amino acids varied from 18.99 – 22.11 g/100 g protein and were significantly higher than the basic amino acids (12.88 – 15.95 g/100 g protein). The amino acid content of the Bacillus amyloliquefacien starter fermented sample was better enhanced than the sample fermented with Bacillus subtilis starter. The study concluded that controlled fermented condiments produced with B. amyloliquefacien culture boosted the amino acids value and profile.