State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, Jiangsu Province, People's Republic of China; School of Food Science and Technology, Jiangnan University, Wuxi 214122, Jiangsu Province, People's Republic of China.
State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, Jiangsu Province, People's Republic of China; School of Food Science and Technology, Jiangnan University, Wuxi 214122, Jiangsu Province, People's Republic of China.
Int J Biol Macromol. 2018 Feb;107(Pt A):129-136. doi: 10.1016/j.ijbiomac.2017.08.152. Epub 2017 Aug 31.
This paper studied the inhibition of water extract of natural or baked black tea on the activity of α-amylase and α- glucosidase. Baking treatment was found to be one effective way to enhance the inhibition of black tea on both α-amylase and α- glucosidase, and IC of water extract of baked black tea (BBTWE) were 1.213mg/mL and 4.190mg/mL, respectively, while IC of water extract of black tea (BTWE) were 1.723mg/mL and 6.056mg/mL, respectively. This study further studied the mechanism of the effect of water extract on α-amylase and α- glucosidase using HPLC, circular dichroism, and synchronous fluorescence. HPLC analysis of tea polyphenols showed that the content of tea polyphenols with low polarity increased after baking. In addition, BBTWE had higer abilty on decreasing the hydrophobicity of tryptophan residues than BTWE for both α-amylase and α- glucosidase.The increase of α-helix proportion of α-amylase when treated with BBTWE was more obvious than that when treated with BTWE. In a word, thermal process of baked foods may be beneficial for tea polyphenols to reduce the rate of starch digestion.
本文研究了天然或烘焙红茶水提取物对α-淀粉酶和α-葡萄糖苷酶活性的抑制作用。烘焙处理被发现是增强红茶对α-淀粉酶和α-葡萄糖苷酶抑制作用的有效方法之一，烘焙红茶水提取物（BBTWE）对α-淀粉酶和α-葡萄糖苷酶的半数抑制浓度（IC）分别为 1.213mg/mL 和 4.190mg/mL，而红茶水提取物（BTWE）对α-淀粉酶和α-葡萄糖苷酶的 IC 分别为 1.723mg/mL 和 6.056mg/mL。本研究进一步使用 HPLC、圆二色性和同步荧光法研究了水提取物对α-淀粉酶和α-葡萄糖苷酶作用的机制。茶多酚的 HPLC 分析表明，烘焙后低极性茶多酚的含量增加。此外，与 BTWE 相比，BBTWE 更能降低α-淀粉酶和α-葡萄糖苷酶中色氨酸残基的疏水性。与 BTWE 处理相比，用 BBTWE 处理时α-淀粉酶α-螺旋比例的增加更为明显。总之，烘焙食品的热加工过程可能有利于多酚类物质降低淀粉消化率。
