The influence of pulse cell wall structure and cellular protein matrix on the in vitro digestion kinetics of starch: A dual encapsulation mechanism.

The intrinsic characteristics and extrinsic processing of whole-pulse food modulate the starch digestion rate and extent. This study investigated the dual encapsulation mechanism of cell wall structure and protein matrix on the in vitro digestion properties of intracellular starch, using an isolated whole-pulse food model of intact pea cotyledon cells subjected to alkaline buffer and enzymatic treatments. Results showed that intact cells with the maximum protein matrix content (18.9 %) exhibited the lowest peak temperature (71.4 °C, uncooked and 58.1 °C, cooked), enthalpy change (3.4 J/g, uncooked and 2.0 J/g, cooked), relative crystallinity (11.6 %), and starch digestion rate (0.0248 min) and extent (11.9 %) compared to alkaline buffer and enzymatic treatments. Even after enzymatic treatment, cells with minimal protein matrix content (1.8 %) exhibited a starch digestion rate (0.0387 min) and extent (39.7 %), which were still lower than those of isolated starch (0.0480 min and 56.8 %). These findings indicate that the protein matrix and cell walls act as a dual encapsulation system to slow starch hydrolysis. This provides a theoretical basis and technical guidance for developing low-glycemic whole-pulse foods.