Starch digestive heterogeneity in different potato varieties: A determinant role of the cell wall permeability

The encasement of cell walls controls the permeability of amylase. In this study, intact cells were isolated from four potato cultivars (XS, ZH, DX, and ZZ). Amylase-sized probe penetration coupled with fluorescence recovery after photobleaching showed the smallest probe diffusion coefficient across the cell walls of raw XS cells, suggesting a stronger hindrance to amylase. Potato cell walls raised gelatinization temperature and reduced pasting viscosity, with the most pronounced effects in the XS cell walls. Microscopic observations indicated that the dissolution of pectin increased the probe penetration into cooked cells, and the probe diffusion coefficient of cooked XS cells was the smallest. In vitro starch digestion revealed that the least permeable XS cell walls significantly reduced starch digestibility, while the most permeable ZZ cell walls did not. Therefore, the permeability of potato cell walls, affected by the dissolution of pectin, effectively governed the starch digestion of intact cells.