Changes of Structure and in Vitro Digestion Properties of Starches in Desi Chickpea Cells Induced by Thermal Treatment

Chickpeas have attracted wide attention of researchers owing to their high nutritional value and low glycemic index. In present study, intact cells isolated from Desi chickpeas were set as the whole chickpea food model to reveal the structure and in vitro digestion kinetics changes of starches in Desi chickpeas subjected to different thermal treatments. The results showed that starch granules in all cell samples were not fully gelatinizatized with certain amounts of relative crystallinity remained, indicating the strong resistance of cells to the thermal treatment. With the temperature of thermal treatment increased, the gelatinization temperature of starches in cell samples enhanced and the enthalpy value decreased. And no significant changes was observed for the enthalpy value of cell samples treated with 100 ℃ including 100D and 70D-100 (ΔH<1.0 J/g), whereas two endothermic peaks were observed for the pressure-heated cell samples (Pre-D). The results of Fourier transform infrared spectroscopy and in vitro digestion kinetics showed that cell samples with lower methyl esterification degree exhibited relatively higher digestion rate and extent. This result indicated that the cell wall structural changes induced by different thermal processing would cause a remarkable impact on the enzyme susceptibility to starch substrates in cells when compared with the remained crystal structure of starches. This study would provide a theoretical basis for the processing of slowly digested chickpea foods.