The solid-state fermentation of soybean protein meal (SPM) by Lactobacillus plantarum Lp6 was studied to evaluate the influence of soluble starch, acid protease and time on the degree of hydrolysis (DH) and viable cell counts (VCC). The fermented SPM (FSPM) was optimized for maximum DH and VCC using response surface methodology. The optimum conditions determined were the following: soluble starch (0.4 g/g of SPM), acid protease (0.1 g/g of SPM) and time (66 h).The optimized values were 22.58% and 9.08 (log cfu/g) for DH and VCC, respectively. Fermentation using the optimized process conditions increased the amount of low molecular weight peptides (<20 kDa) compared to SPM with high molecular weight polypeptides (>97.4 kDa). The protein content (60.15%) of FSPM increased following fermentation of SPM. The free amino acids profile (0.32 to 8.03 g/100 g protein) and protein solubility (29.33% to 38.35%) increased significantly (P < 0.01) during fermentation due to the hydrolytic actions of L. plantarum Lp6 and acid protease. PRACTICAL APPLICATIONSSoybean is one of the best known vegetable protein in the world. During solid-state fermentation process, this study demonstrated that the nutritional attributes of soybean protein meal (SPM) could be enhanced by fermentation with Lactobacillus plantarum Lp6. These results would encourage production of bioactive peptides with the possible cheap source of protein in an industrial scale to improve the nutritional value of SPM. This is bound to increase the volume of SPM as a by-product of soybean oil-processing industries.

Food proteins have gained increasing value in recent times because of the rapidly expanding research and knowledge based on the contents of encrypted physiologically active amino acid sequences (Miguel, Alonso, Salaices, Aleixandre, & López-Fandiño, 2011). Proteins from food sources usually contain specific peptide sequences that remain inactive when present as intrinsic parts of the primary protein structure and one of the most reliable ways to release these peptides is through enzymatic hydrolysis of parent protein (Aluko, 2015).

Purpose The purpose of this study was to compare the physico-chemical properties and amino acid profile of three maize hybrid cultivars grown in Nigeria. Design/methodology/approach Two normal maize endosperm varieties, yellow SUWAN-ISR (YNM) and white ART/98/SW05-OB-WC (WNM), and one yellow QPM variety, TZE-POP-DT-STR-QPM (YQPM), were selected for the study. Physico-chemical properties, physical tests, proximate composition analysis, functional properties and characteristics and amino acid profile tests were carried out on the grains using standard methods. Findings Protein was significantly higher (p < 0.05) in YQPM (10.49 per cent) than in normal endosperm, YNM (8.83 per cent) and WNM (8.50 per cent). Amino acid profile of the grains revealed that total amino acid of YQPM (94.67 g/100 g of protein) and essential amino acid of YQPM (39.070) were the highest among the three, with highest significantly different value of tryptophan (0.388 g/100 g of protein) at p < 0.05. The cooking quality of YQPM was found to be better than the other two, with highest hydration capacity and increase in volume after cooking (90.8 ± 0.01 g/1000 grains and 147.53 ± 0.02 per cent). Originality/value YQPM will be highly beneficial in the tropics, where maize is grown as the major staple food to reduce hunger and malnutrition because of its amino acid balance and its better cooking quality.

ABSTRACT/g) and foam capacity (KPC, 15.00%; KPI, 3.00%). Foaming and emulsifying properties were improved at alkaline pH and higher salt concentration. In conclusion, the high water absorption capacity, gelling ability and in vitro protein digestibility exhibited by kariya protein products could make them useful ingredients in food applications. PRACTICAL APPLICATIONSThe study provides information about the properties of proteins produced from kariya seeds (an underutilized oilseed). From the results, high protein content can be produced from kariya seeds by producing concentrates and isolates from it and this could be used in food fortification. Also, the results obtained revealed that kariya protein concentrates and isolates have high functional properties and in vitro protein digestibility and therefore can serve as ingredients in food formulations.

PRACTICAL APPLICATIONSThe study compares the bioactivity of peptides produced from kariya seeds (an underutilized oil seeds) using two different proteolytic enzymes (pepsin and pancreatin). The result showed that kariya seed protein hydrolyzed with pancreatin has better functional properties than those hydrolyzed with pepsin. However, kariya seed protein hydrolyzed with pepsin has better antioxidant properties than those hydrolyzed with pancreatin. Both results compare favorably with that of other oilseeds. Therefore, good functional and antioxidant properties can be produced from hydrolyzed kariya proteins.