Improvement in textural, structural and digestive characteristics of maize gruel using malt amylase obtained by germination and ultrasonic extraction

To improve the quality of maize gruel in a cost-effective and additive-free manner, endogenous malt amylases (EMA) produced from sprouted malt were used to treat maize gruel. The effects of EMA on the structural and digestibility properties of maize gruel were investigated. The highest enzyme activity (328.86 U/g) was obtained after 3 days of malt germination, combined with ultrasonic extraction for 30 min at a solid-liquid ratio of 1:10 and an extraction temperature of 50 °C. Compared to native maize gruel, EMA treatment disrupted the integrity and particle size of maize grains, reduced starch crystallinity from 17.4 ± 0.31% to 12.39 ± 0.22%, and significantly lowered hardness, elasticity, stickiness, and chewability values. The digestibility of treated maize gruel increased by 31.31 ± 0.92% in gastric fluids and by 31.76 ± 1.13% under the combined action of gastric and intestinal fluids. EMA was confirmed as an effective natural modifier for improving the structural characteristics, nutritional quality, and digestibility of maize gruel. • Nature endogenous malt amylases with the highest enzyme activity were produced. • A green malt amylases hydrolytic method was developed to improve maize gruel quality. • Improvements in textural and structural characteristics of maize gruel. • Limited hydrolysis enhanced nutritional and digestive properties of maize gruel.