In vitro dynamic release of glucose and key ions with phytase improves starch digestion kinetics and enzyme efficiency in cereal substrates

Phytic acid (IP 6 ), a predominant anti-nutritional factor in cereal grains, impairs mineral absorption and interferes with digestive enzyme activity, reducing nutrient utilization in monogastric animals. While microbial phytase is commonly used to hydrolyze IP 6 and improve phosphorus bioavailability, its potential to modulate the dynamics of starch digestion, particularly the kinetics of glucose release, remains underexplored. This study evaluated the effects of varying levels of phytase (0, 500, 1000, and 1500 U/kg) on IP 6 hydrolysis, ion release, glucose release dynamics, and enzyme activities during in vitro digestion of corn, wheat, and broken rice. The results showed that phytase supplementation significantly enhanced IP 6 degradation (>96 % at 500 U/kg) and increased mineral ion release, with plateau effects at higher doses. Elevated phosphate and calcium were positively associated with α-amylase activity, accelerating starch digestion. Broken rice showed the greatest hydrolysis and glucose release, likely due to low amylose content and improved enzyme accessibility. Residual amylase activity peaked at 500 U/kg but declined at higher doses. Correlation analysis confirmed strong interactions among cereal composition, phytate hydrolysis, ion release, enzyme function, and starch digestion kinetics. Overall, phytase not only improves mineral bioavailability but also modulates glucose release dynamics, supporting more efficient energy utilization in cereal-based diets. • Phytase enhanced starch digestion dynamic in corn, wheat, and broken rice • Ion release increased with phytase dose, especially phosphate and calcium • Phytase improved residual amylase and phytase activity during digestion • Starch digestion kinetics correlated with phytase-driven mineral release • Broken rice showed highest starch digestibility but lowest phytic acid content