Influence of pretreatments methods on chemical composition and physico-chemical properties of potential protein sources for plant-based food applications

Abstract

The reliance on soybeans has restricted plant protein diversification for global food security amidst population growth and changing climate. This study evaluated the effect of fermentation (72 h, 25 °C ± 2) and boiling (100 °C, 10 min) on the physico-chemical properties of six potential plant protein sources; rice bran (RB), bambara groundnut (BN), moringa seed (MS), mung bean (MB), sesame (SS), and jack bean (JB), compared to soybean (SB). Protein composition varied (14.98-30.29 g/100g) across samples. Fermentation increased protein composition (p<0.05), while boiling had no significant effect. Bulk density and whiteness index were reduced by 5-12% after fermentation, while yellowness and swelling capacity were enhanced. Protein solubility (PS) increased with pH 2-10 across all samples, with similar pattern observed in SB. Fermentation improved PS, while boiling had mixed effects. Phytate (13.47-37.19 mg/g, SS-RB) and oxalate (6.50-12.50 mg/100g, RB-JB) reduced after both pre-treatments. The molecular weights of major protein bands, under non-reducing conditions, ranged from 17-100 kDa, varying by sample. SDS-PAGE analysis showed a similar pattern of invitro protein digestion after 240 min. Fermentation enhanced the properties of the plant protein sources more effectively than boiling, with MS and BN exhibiting superior compositions and digestibility compared to soy for potential food applications.