挤压膨化辅助提取米糠可溶性膳食纤维及其特性研究

摘要

以新鲜米糠为原料,在单因素和正交试验基础上,通过分析不同挤压工艺和酶解条件对米糠中可溶性膳食纤维提取率的影响,优化挤压膨化辅助酶水解技术提取可溶性膳食纤维.同时采用扫描电子显微镜、差示扫描热量法等表征可溶性膳食纤维的结构及物化特性.试验结果表明,在挤压温度130℃、螺杆速度200 r/min、物料含水量20％,酶用量2.0％、酶解温度75℃、酶解时间90 min、pH6.0的条件下,可溶性膳食纤维提取率为30.35％.米糠可溶性膳食纤维表面形态疏松,呈蜂窝颗粒状,内部由纤维素类物质形成支撑主体,热力学相对稳定.与未经挤压膨化处理提取的可溶性膳食纤维相比,挤压辅助提取的可溶性膳食纤维具有更高的持水力、结合水力、溶胀力、结合脂肪能力及丰富的空间网状结构,结构及物化特性均得到明显改善.%In this paper,the process of extrusion-assisted enzymatic hydrolysis to extract the soluble dietary fiber was optimized based on single factor and orthogonal experiments,with fresh rice bran as the material.In addition,the effect of different extruding processes and enzyme conditions on the soluble dietary fiber content was analyzed.At the same time,the physicochemical properties of soluble dietary fiber were presented by scanning electron microscope (SEM) and differential scanning calorimeter (DSC).The results showed that soluble dietary fiber had high productivity of 30.35％ under the condition of extrusion temperature of 130 ℃,the screw speed of 200 r/min,material water content of 20％,enzyme dosage of 2.0％,enzymatic hydrolysis temperature of 75 ℃,hydrolysis time of 90 min,pH of 6.0.The surface morphology of rice bran soluble dietary fiber was loose and honeycomb.Inter body was composed of cellulose material,which made a relatively stable thermodynamics of soluble dietary fiber.Compared with the un-extrusion processing,the soluble dietary fiber extracted by the extrusion-assisted had higher retention ability,water binding ability,swelling ability,bound fat ability,and the structure characterization and physiological functional properties were improved.