Insights into the relations between cell wall integrity and in vitro digestion properties of granular starches in pulse cotyledon cells after dry heat treatment

Abstract

Natural foods, such as whole pulses, are recommended in the dietary guidelines of the US and China. The plant cell wall structure in whole pulses has important implications for the nutritional functionalities of starch. In this study, garbanzo bean cells with varying degrees of cell wall integrity were subjected to dry heat treatment (DHT) and used to elucidate the food structure-starch digestion properties of pulse food. The morphological features suggested that all cell samples do not exhibit remarkable changes after being subjected to DHT. Molecular rearrangement and the crystallite disruption of starch granules entrapped in cells occurred during DHT as assessed by the crystal structure and thermal properties. DHT decreased the inhibitory effects of enzymes of both the soluble and insoluble components, but the digestion rate and extent of slightly and highly damaged cell samples did not exhibit significant differences compared with their native counterparts. We concluded that the starch digestion of pulse cotyledon cells is primarily determined by the intactness of the cellular structure. This study reveals the role of food structure on the ability to retain the desirable nutritional properties of starch after subjection to physical modification.