Duan Shuting, Li Cheng
Food & Nutritional Sciences Programme, School of Life Sciences, The Chinese University of Hong Kong, Shatin 999077, Hong Kong, China.
Food & Nutritional Sciences Programme, School of Life Sciences, The Chinese University of Hong Kong, Shatin 999077, Hong Kong, China.
Int J Biol Macromol. 2025 Jul;318(Pt 1):145045. doi: 10.1016/j.ijbiomac.2025.145045. Epub 2025 Jun 6.
Although it is well known that both retrogradation and presence of tannic acid can reduce starch digestibility, their combined impact on starch digestibility is not clear. To this end, wheat starch was added with varying contents of tannic acid, and their digestibility was evaluated after different retrogradation periods. Notably, starch digestibility was significantly increased after the addition of 5 % and 10 % tannic acid, while decreased when 20 % tannic acid was added. Mechanistically, it was found that tannic acid at low concentrations (5 % - 10 %) promoted starch digestibility by inhibiting starch intermolecular interactions and reducing its long-range ordering during retrogradation. In comparison, tannic acid at high concentrations (i.e., 20 %) reduced starch digestibility, primarily through increasing the free tannic acid content and inhibiting enzymatic activities of both pancreatin and amyloglucosidase. Collectively, these results revealed, for the first time, a competitive inhibition mechanism between tannic acid and retrogradation on starch digestibility, which could be applied in the future to develop staple foods with slow starch digestibility.
虽然众所周知，回生和单宁酸的存在都会降低淀粉消化率，但它们对淀粉消化率的综合影响尚不清楚。为此，向小麦淀粉中添加了不同含量的单宁酸，并在不同的回生期后评估其消化率。值得注意的是，添加5%和10%的单宁酸后，淀粉消化率显著提高，而添加20%的单宁酸时则降低。从机制上讲，发现低浓度（5% - 10%）的单宁酸通过抑制淀粉分子间相互作用并减少回生过程中淀粉的长程有序性来促进淀粉消化率。相比之下，高浓度（即20%）的单宁酸降低淀粉消化率，主要是通过增加游离单宁酸含量并抑制胰蛋白酶和淀粉葡糖苷酶的酶活性。总的来说，这些结果首次揭示了单宁酸和回生对淀粉消化率的竞争抑制机制，未来可应用于开发淀粉消化缓慢的主食。
