Physicochemical properties, anti-nutritional and bioactive constituents, in vitro digestibility, and techno-functional properties of bioprocessed whole wheat flour.

Abstract

This study investigated the impact of bioprocessing techniques (germination, solid-state fermentation, the combination of germination, and solid-state fermentation) on the physicochemical properties, anti-nutritional and bioactive constituents, in vitro digestibility, and techno-functional properties of whole wheat grains were investigated. Bioprocessed whole wheat flour (WWF) samples and the raw flour (control) were prepared using standard procedures. Proximate, anti-nutritional, mineral and amino acid (AA) compositions, protein digestibility, antioxidant activities, starch characteristics, and techno-functional properties were studied using standard methods. The bioprocessing methods increased (p≤0.05) the protein (13.37-16.84g/100g), total dietary fiber, mineral constituents, resistant starch (7.19-9.87g/100g), slowly digestible starch, phenolic content, antioxidant activities (ferric reducing antioxidant power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity), most AAs, and protein digestibility. Also observed were decreases (p≤0.05) in rapidly digestible starch, phytic acid, tannin, and trypsin inhibitor activity. The adopted bioprocessing techniques modified the thermal, functional, color, and pasting properties of the WWF and resulted in molecular interactions in some functional groups, as revealed by Fourier transform infrared spectroscopy, compared to the raw flour. The combination of germination and fermentation improved the physicochemical (titratable acidity=4.93%), protein (16.84/100g) and starch digestibility (resistant starch=9.87%), antioxidant (FRAP=78.90mg/GAE/100g), and mineral contents (calcium=195.28mg/100g), modified the pasting (peak viscosity=90.34 RVU), thermal (peak temperature=64.82°C), and color properties of WWF with reduced anti-nutritional factors. The combination of these processing techniques could serve as a natural and low-cost technique for the modification of whole wheat functionality and subsequently as an improved functional ingredient during food product development.