Rheological, structural, and water-immobilizing properties of mung bean protein-based fermentation-induced gels: Effect of pH-shifting and oil imbedment

The objective of this study was to investigate the impact of pH-shifting and oil inclusion on the textural properties of plant protein-based fermentation-induced gels resembling dairy yogurt in consistency. Gels were formed by pH12-treated or native mung bean protein (MBP) with or without emulsified coconut oil (3% w/v) and transglutaminase (0.1% w/w protein) during fermentation at 43 °C for 8 h. Quinoa flour hydrolysate was used to modulate the MBP gel network. Creep-recovery and viscoelasticity (Gʹ/Gʹʹ) tests showed that gels prepared with pH12 treated MBP were less deformable and stiffer than native MBP gels. The pH12 treated MBP gels also exhibited superior hardness and water-holding capacity over the native MBP gels. Consistently, the pH12 gels displayed more compact and denser network structures, and oil emulsion droplets as well as transglutaminase further contributed to such packing effect. 1H-LF-NMR confirmed less mobility of bulk water in pH12 gels compared with native gels.