交联化和双酶法改性小米糠膳食纤维的结构及性质变化

Structural and Property Changes of Millet Bran Dietary Fiber Modified via Cross-linking and Dual-enzymatic hydrolysis

摘要:

小米糠是小米脱粒所产生，富含膳食纤维且低廉易得，但多被用作动物饲料或直接丢弃，利用率低。为了提高小米糠膳食纤维的功能特性与利用率，该文分别用双酶法和交联化对小米糠膳食纤维进行改性，研究了改性后小米糠膳食纤维在成分、理化性质及功能活性方面的变化。结果表明，两种方法改性后的小米糠膳食纤维有碎片化、多孔的微观结构，更高的可溶性膳食纤维含量、黏度、持水力、NO2-吸附力、胆固醇吸附力以及阳离子交换能力。经交联化和双酶法改性后的小米糠膳食纤维中可溶性膳食纤维含量分别从1.04 g/100 g增加至10.72 g/100 g和6.11 g/100 g；NO2-吸附能力从62.40 μg/g分别增加至92.63 μg/g和82.47 μg/g；持水力从2.26 g/g增加至3.39 g/g和4.74 g/g。双酶法改性后葡萄糖扩散阻滞系数有所降低，但其吸水膨胀性从0.35 mL/g提高至0.84 mL/g。由此可见，交联化和双酶法改性均可以有效提高小米糠膳食纤维中的可溶性纤维含量和功能性质，该研究为提高小米糠膳食纤维在食品领域的应用提供了理论根据。

Abstract:

Millet bran is produced by millet threshing. It is rich in dietary fiber and is inexpensive and easy to obtain but is mostly used as animal feed or directly discarded, resulting in a low utilization rate. To improve its functional characteristics and utilization, millet bran dietary fiber (MBDF) was modified via dual-enzymatic hydrolysis and cross-linking, respectively, and changes in the composition, physicochemical properties, and functional properties of the modified MBDF were studied. The results showed that the modified MBDF had a more fragmented and porous microstructure; higher soluble dietary fiber content; and greater viscosity, water-holding capacity, NO2- adsorption capacity, cholesterol adsorption capacity, and cation exchange capacity. After crosslinking and dual-enzyme modifications, the content of soluble dietary fiber in MBDF increased from 1.04 g/100 g to 10.72 g/100 g and 6.11 g/100 g, respectively; the NO2- adsorption capacity increased from 62.40 to 92.63 and 82.47 μg/g, respectively; and the water holding capacity increased from 2.26 to 3.39 and 4.74 g/g, respectively. The glucose diffusion retardation coefficient decreased after dual-enzyme modification, but its water absorption and swelling capacity increased from 0.35 to 0.84 mL/g. Therefore, the soluble fiber content and functional properties of MBDF can be improved by cross-linking and dual-enzyme modifications. This study provides a theoretical basis for improving the application of MBDF in the food industry.