Effect of media milling on emulsifying capabilities and starch digestion properties of black rice particles : the role of multi-level structure changes in starch

Abstract

The multi-level structure of starch is the prime determinant of whole-grain functionality and digestibility. Whole-grain are often treated as an undifferentiated whole, leaving the specific role of the starch matrix unresolved. This study employed black rice particles (BRPs) to unravel how media milling-induced changes in starch multilevel structure govern their emulsifying capacity and digestibility. Media milling significantly reduced BRPs particle size, degraded amylopectin and amylose, reduced short-range order and crystallinity. These structural modifications enhanced functionality (108 % and 173 % increases in water- and oil-holding capacities), improved emulsification, and accelerated digestibility rate (0.016 to 0.039 min−1) without affecting maximum digestibility. Overall, media milling effectively tailors the multilevel structure of starch in BRPs to enhance functionality and digestibility. These findings provide a theoretical foundation for developing innovative whole grain-based functional foods.