Tertiary enzyme synergistic network-mediated starch-directed transformation into resistant starch

Pea starch was modified with different combinations of α-amylase, 4-α-glucanotransferase, and pullulanase, to produce eight types of resistant starch. The results showed that, compared to pea starch, the triple-enzyme-modified starch showed a 37.51 % reduction in branching degree after gelatinization. Moreover, its crystal structure transformed from C-type to B-type, with crystallinity increasing to 37.21 %. Enzymatic modification increased the proportions of B1 and B2 chains. This structural reorganization significantly increased the resistant starch content and reduced the glycemic index. The maximum resistant starch content reached 56.77 %, while the glycemic index decreased by 9.43 %. After cooking, the resistant starch content declined. However, the resistant starch content of the starch that underwent gelatinization and triple-enzyme treatment remained above 30 %. After cooking, the glycemic index remained at a medium level, with the lowest value recorded at 62.78. This study provides a theoretical basis for the development of functional starch.