Effects of Cell Wall Damage on Physicochemical and Digestibility Properties of Intracellular Starch in Potato Cells

This study aimed to investigate the effect of cell wall damage on the physicochemical properties of intracellular starch. The intact potato cells were isolated using pectinase, and then cells with different degrees of cell wall damage were prepared by cellulase treatment for 2 and 4 h. The changes in intracellular starch structure and physicochemical properties (viscosity property, thermal property and digestion property) were investigated. The results showed that cellulose in the cell walls was hydrolyzed as enzymatic hydrolysis time increased, leading to increased cell wall damage, leakage of starch granules from cells, reduced protein content and decreased cell size. The damage to the cell wall enhanced the interaction between starch granules and water molecules, resulting in increased swelling power and solubility of potato cells and a lower gelatinization temperature. Potato starch showed the lowest gelatinization temperature (Tp=68.49 ℃). Cells treated with cellulase for 2 h showed the highest peak viscosity (4616.0 cP), this was attributed to the strong water absorption by cell wall polysaccharides and rapid starch swelling inside and outside the cells. Compared with potato starch, the presence of intact and damaged cell walls inhibited the hydrolysis of starch, and the broken cell wall weakened the barrier effect between digestive enzymes and starch. The resistant starch (RS) content in cells treated with cellulase for 4 h was 4.74% lower than that in intact potato cells, while potato starch showed the lowest RS content (39.91%). In summary, cells with varying degrees of cell wall damage exhibited significant differences in functional properties, providing novel insights and a theoretical foundation for the application of potato as a staple food.