Preparation of resistant starch from lotus root by autoclaving and multi-enzyme hydrolysis: Structural characteristics, physicochemical properties and anti-inflammatory activities

Resistant starch (RS), as a natural plant active ingredient, had been widely used in preventing or alleviating colitis due to its anti-digestive and anti-inflammatory properties. In this study, starch was extracted from lotus root (LS), and RS was prepared using physical (autoclaving) and biotechnological (pullulanase debranching) methods. Lotus root resistant starch type III (LRS) was then purified using amyloglucosidase and porcine pancreatic α-amylase. A comprehensive analysis was conducted on the structural and physicochemical characteristics and in vivo anti-inflammatory activities of LRS. The findings revealed that autoclaving and enzymatic treatment increased the solubility and thermal stability of the starch, reduced the swelling power, and changed the crystalline type from CA-type to B-type. More importantly, the amylose content and molecular order of LRS were increased, which promoted the formation of crystalline structures and significantly increased the anti-digestive ability of starch. Animal experiments showed that LRS was effective in alleviating colitis. After the intervention of LRS, the levels of IL-10, T-AOC, SOD and CAT were significantly increased, while the levels of IL-6, TNF-α and MDA were significantly decreased in the colon of mice. In addition, LRS was able to improve gut microflora dysbiosis as well as promote the production of SCFAs. These results suggested that LRS had a great potential in the field of functional foods.