Starch digestion in intact pulse cotyledon cells depends on the extent of thermal treatment

Abstract Starch digestion in cellular matrices is primarily determined by the hindrance of cell walls limiting enzyme diffusion as well as the retention of starch granular structure. However, the effect of hydrothermal treatment on structure and digestion properties of entrapped starches is not fully elucidated. In present study, we reported the variations in structure and enzyme susceptibility of two pulse cells isolated at 60°C followed by heated at 70, 80, 90, 100°C, which are higher than the starch gelatinization temperature. Based on the thermal and crystalline properties, entrapped starches in cells are not fully gelatinized even treated at 100°C. Whilst, the digestion of entrapped starches increases with higher temperature, but still lower than the isolated starch treated at the same temperature. In addition to physical barriers (intact cell wall) and starch structural features (partial ordered crystalline structure), the soluble/insoluble proteinaceous materials in cells also synergy reduce the starch hydrolysis.