Heat-induced Pleurotus ostreatus protein gel improved by konjac glucomannan: Physicochemical, gel and structural properties

This study investigated the influence of konjac glucomannan (KGM) on the physicochemical and structural properties of Pleurotus ostreatus protein (POP) gels, and explored the potential mechanism. Results demonstrated that konjac glucomannan (KGM) addition reduced turbidity, increased Zeta-potential and particle size, and promoted solution stability. Lower KGM addition (0.1 %-0.6 %) significantly improved the hardness, elasticity, chewiness, water holding capacity (WHC), storage modulus, and loss modulus of POP gels, especially for the 0.6 % KGM addition. However, higher addition of KGM (0.8 %-1.0 %) decreased the textural properties and WHC of POP gels. Secondary structure analysis showed that adding 0.6 % KGM increased the alpha-helix content from 13.76% to 17.82%, while the (1-sheet content increased from 31.06% to 45.45%. Molecular forces and scanning electron microscopy showed that the addition of KGM enhanced the hydrogen bond and disulfide bond, promoting the formation of a denser network structure with good uniformity of the composite gels. Principal component and correlation analysis showed that hardness and WHC of the gels had high positive correlation with hydrogen bond, disulfide bond, (1-sheet and random coil. This study provided a foundation for using KGM/POP composite gels in plant-based substitutes.