沅江芦笋低聚木糖制备工艺优化、结构鉴定及抗氧化性研究

Preparation Process Optimization,Structure Identifification and Antioxidant Activity of Xylo-Oligosaccharides from Miscanthus Lutarioriparius

采用响应面法优化沅江芦笋低聚木糖制备工艺,并对其进行结构鉴定和抗氧化性分析。先采用酶解法制备芦笋低聚木糖,随后采用Sevage法除蛋白,再分别采用紫外光谱、扫描电镜、傅立叶红外光谱、高效液相色谱对芦笋低聚木糖进行结构鉴定,并测定了其抗氧化性。最优工艺条件为:酶解pH5.1、酶解温度48℃、时间14.5 h、木聚糖酶添加量0.38%,最终低聚木糖得率为(29.94±0.53)%。结构鉴定表明,芦笋低聚木糖以木二糖、木三糖和木四糖为主,且主链是由β-D-木糖通过β-1,4糖苷键连接而成,侧链包含少量葡萄糖醛酸,具有不规则的孔洞结构。抗氧化性试验表明,芦笋低聚木糖对1,1-二苯基-2-三硝基苯肼(1,1-Diphenyl-2-picrylhydrazyl,DPPH)自由基和2,2-联氨-双-3-乙基苯并噻唑啉-6-磺酸(2,2’-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid),ABTS)阳离子自由基的IC_(50)值分别为0.817、2.256 mg/mL,对铁离子还原力的IC_(50)值为6.135。该研究结果可为沅江芦笋低聚木糖的功能食品开发提供理论依据。

Response surface methodology was used to optimize the preparation process of xylo-oligosaccharides from Miscanthus lutarioriparius,and the structure and antioxidant activity of the prepared xylo-oligosaccharides were identied.The xylo-oligosaccharides were first prepared by enzymatic hydrolysis,followed by Sevage method to remove protein,and then the identification of Miscanthus lutarioriparius xylo-oligosaccharides was carried out by ultraviolet spectrum,scanning electron microscopy,Fourier transform infrared spectroscopy,and high performance liquid chromatography,and the antioxidant activity were determined.The optimum conditions were determined as follows:enzymatic hydrolysis at pH5.1,temperature of 48℃,time of 14.5 h,and xylanase addition of 0.38%,under these conditions,the yield of xylo-oligosaccharides was(29.94±0.53)%.The structural identification showed that xylo-oligosaccharides was primarily composed of xylobiose,xylotriose,and xylotetraose,and the main chain was composed ofβ-D-xylulose linked byβ-1,4 glycosidic bonds,and the side chain contained a small amount of glucuronic acid with an irregular pore structure.Antioxidant activity tests showed that xylo-oligosaccharides had IC_(50)values of 0.817 mg/mL and 2.256 mg/mL for clearing 1,1-diphenyl-2-picrylhydrazyl(DPPH)radical and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid)(ABTS)radical cation,respectively,and an IC_(50)value of 6.135 for ferric ion reduction.This study provides theoretical basis for the development of functional food products based on xylo-oligosaccharides from Miscanthus lutarioriparius.