Enhancing enzymatic resistance of pea type 3 resistant starch through pressure heating and annealing

Type III resistant starch (RS3) is an important functional food ingredient. In this study, RS3 was prepared by retrogradation of pea starch after acid hydrolysis and pullulanase debranching. Heat-moisture treatments, including annealing (90 °C, 40-70 % moisture content) and pressure heating (121 °C, 10-40 % moisture content), were employed to further enhance the RS content of pea RS3. The relationship between the structural changes and digestibility of pea RS3 was investigated. The results showed significant increases in relative crystallinity, particle size, gelatinization temperature, and RS content, while swelling power, pasting viscosity, and rapidly digestible starch content were markedly decreased after heat-moisture treatment. A strong positive correlation (r = 0.94*) was observed between relative crystallinity and RS content. The highest RS content of 85.6 % was achieved after pressure heating at 20 % moisture content, which was notably higher than the 45.6 % RS content before heat-moisture treatment. This study highlights the beneficial effects of annealing and pressure heating in enhancing RS content in pea RS3, providing valuable insights for developing RS3 with high RS content after cooking.