米糠水溶性膳食纤维理化特性及抗氧化性

Physicochemical Properties and Antioxidant Activity of Water-Soluble Dietary Fiber from Rice Bran

以超声辅助纤维素酶水解脱脂米糠提取得到的水溶性膳食纤维(water-soluble dietary fibre,SDF)为原料,研究其理化性质和功能特性,发现米糠SDF纯度较高,为(79.52±0.07)%,其蛋白质和灰分含量少,分别为(7.82±0.13)%、(5.71±0.11)%。优化提取的米糠SDF具有良好的理化性质:持水力为(3.16±0.15)g/g、持油力为(0.99±0.08)g/g、溶胀性为(1.39±0.12)m L/g、结合水力为(4.18±0.10)g/g。米糠SDF具有一定的阳离子交换能力,其溶解性与温度成正比。傅里叶变换红外光谱分析发现,米糠SDF中处于缔合状态的氢键较多;扫描电子显微镜分析超微结构结果表明其纯度较高。米糠SDF表现出较强的抗氧化能力,随质量浓度的升高呈明显上升趋势,10 mg/m L的SDF对1,1-二苯基-2-三硝基苯肼自由基清除率为20.27%,对2’-联氨-双-3-乙基苯并噻唑啉-6-磺酸自由基清除率达到58.97%。

This study evaluated the physicochemical and functional properties of water-soluble dietary fiber （SDF） prepared by ultrasonic-assisted cellulase hydrolysis of defatted rice bran. The SDF, with a high purity of （79.52 ± 0.07）%, had low protein and ash contents of （7.82 ± 0.13）% and （5.71 ± 0.11）%, respectively. The SDF had good physical and chemical properties; its water-holding capacity was （3.16 ± 0.15） g/g, oil-holding capacity （0.99 ± 0.08） g/g, swelling capacity （1.39 ± 0.12） mL/g, and water-binding capacity （4.18 ± 0.10） g/g. It was also found that the SDF had cation exchange capacity, and its solubility was positively proportional to temperature. Fourier transform infrared spectral analysis indicated the presence of some associated hydrogen bond in the SDF. Scanning electron microscopic analysis confirmed its high purity. Furthermore, the SDF exhibited strong antioxidant capacity in a concentration-dependent manner, which was determined to be 20.27% and 58.97% in the scavenging of 1,1-diphenyl-2-picrylhydrazyl and 2,2’-azinobis-（3-ethylbenzthiazoline-6- sulphonate） radicals at 10 mg/mL, respectively.