改性条件对米糠不溶性纤维功能性质的影响

Effects of Different Treatments and Modification on the Functional Properties of Rice Bran Dietary Fiber

为了探讨碱处理浓度对米糠不溶性纤维成分的影响以及化学组成与纤维物理性质之间的关系,采用酸碱结合的方法从米糠中提取不溶性纤维。结果显示,随着碱质量浓度增大,淀粉、蛋白和半纤维素的水解率逐渐增大,所得米糠不溶性纤维的持水力逐渐降低,持油力逐渐升高,膨胀力先升高后降低。为改善米糠不溶性纤维的亲水性与可溶性,提高其对淀粉酶和胰脂酶的抑制作用,进一步采用羧甲基改性,考察了羧甲基改性前后的米糠纤维样品的理化性质以及对淀粉酶和胰脂酶的抑制作用变化。结果表明:羧甲基化改性显著提高了米糠不溶性纤维的持水力和膨胀力,而且通过羧基与酶之间的静电相互作用,显著增强了纤维对胰脂酶的抑制作用。

A series of rice bran dietary fiber,which possess different physicochemical properties,were obtained by treating defatted rice bran with different concentrations of potassium hydroxide(KOH).The relationship between composition and physicochemical properties were discussed.Moreover,the effects of successive carboxymethylationon the physicochemical properties and subsequent influence on the a-amylase and lipase inhibition capacity of selected rice bran fiber were comparatively investigated.An increase in theoil binding capacitybut the decrease in the water holding capacitywith the incremental KOH concentration was observed,which was mainly due to the reduced hydration groups with the removal of starch,protein and partial hemicelluloses.The hydration capacities and oil binding capacity as well as the inhibiting capacities to lipase of rice bran dietary fiber were significantly enhanced after carboxymethylation.