甘草渣膳食纤维提取工艺研究

以甘草渣为原料,用水浴加磁力搅拌方法辅助,分别对可溶性和不溶性膳食纤维进行碱提,利用单因素试验和正交试验对提取条件进行优化,确定最佳提取工艺为:料液比1∶9(g/mL)、提取温度40℃、提取时间80 min、氢氧化钠浓度6%时,不可溶膳食纤维得率最大为81.33%;料液比1∶10(g/mL)、提取温度80℃、提取时间80 min、氢氧化钠浓度7%时,可溶膳食纤维得率最大为8.33%。采用理化分析方法,对提取物进行功能特性的测定,测定结果为:不可溶膳食纤维的持水力为3.73 g/g,膨胀力为5.00 mL/g;可溶膳食纤维的溶解度为0.02 g/mL,膨胀力为0.50 mL/g。该研究为提取膳食纤维提供一条新途径,为甘草渣的再利用提供一种新思路。

蛹虫草、山楂提取物固体饮料制备工艺研究

以水提醇沉法提取得到蛹虫草提取物和山楂提取物,分别对其主要活性成分进行测定。结果表明:蛹虫草提取物、山楂提取物均含总糖(44.53%、43.78%)、还原糖(6.90%、8.08%)、蛋白质(31.19%、3.87%)、黄酮(1.20%、2.16%)等活性成分。利用蛹虫草提取物、山楂提取物研制固体饮料,以感官评价为标准,采用单因素、正交试验方法优化蛹虫草、山楂提取物固体饮料配方,结果表明:将蛹虫草提取物0.5 g、山楂提取物2.0 g、木糖醇2.0 g、柠檬酸0.05 g溶于100 mL热水中,在此条件下,该固体饮料溶解度为98.35%,外观形态、色泽、风味、口感均为最佳,且符合GB/T29602-2013《固体饮料》标准。

大学生网络信息行为综合指标体系构建研究——基于改进数据包络分析法

[目的/意义]结合现阶段大学生网络信息行为研究成果,提取出大学生网络信息行为的5类构成要素,即大学生个体、信息素养、信息查询活动、信息使用活动和信息交互活动,从而构建用于描述大学生网络信息行为的综合指标体系。[方法/过程]采用后退法思想对数据包络模型中的投入变量及产出变量的效率向量进行剔除,最终得出31个三级指标作为大学生网络信息行为评价的依据。[结果/结论]研究结果表明对于大学生网络信息行为而言,大学生个体及大学生网络信息需求两个一级投入指标对于大学生网络信息行为3个一级产出指标信息查询活动、信息使用活动、信息交互活动具有显著影响,这5类要素共同构成了大学生网络信息行为指标体系。

非理想电网下基于双基波分量提取的APF研究

提出一种基于双基波分量提取的三相四桥臂并联有源电力滤波器(SAPF)新型补偿电流检测算法,该算法无需锁相环(PLL)和低通滤波器(LPF),通过两个自校正滤波器(STF)结合传统的ip-iq、法,分别对电源电压和负载电流的基波分量进行提取,在非理想电网电压条件下可以有效抑制谐波、补偿无功。采用Simulink仿真并搭建了模拟样机。仿真和实验结果表明了该算法的有效性和实用性。

Comparative evaluation of polysaccharides isolated from Astragalus,oyster mushroom,and yacon as inhibitors of α-glucosidase

The incidence of diabetes has increased considerably, and become the third serious chronic disease following cancer and cardiovascular diseases. Though acarbose, metformin, and 1-deoxynojirimycin have good efficacy for clinical application as hypoglycemic drugs, their expensive costs and some degree of side effects have limited their clinical application. Recently, increasing attention has concentrated on the polysaccharides from natural plant and animal sources for diabetes. In order to illustrate the pharmaceutical activity of polysaccharides as natural hypoglycemic agents, polysaccharides isolated from Astragalus, oyster mushroom, and Yacon were evaluated for their inhibitory effects on α-glucosidase. Polysaccharides were extracted and purified from Astragalus, Oyster mushroom, and Yacon with hot water at 90 °C for 3 h, respectively. The total sugar content of the polysaccharide was determined by the phenol-sulfuric acid method. The α-glucosidase inhibitory activity was measured by the glucose oxidase method. The results exhibited that the inhibitory effects on α-glucosidase were in decreasing order, Astragalus > oyster mushroom > Yacon. The α-glucosidase inhibition percentage of Astragalus polysaccharide and oyster mushroom polysaccharide were over 40% at the polysaccharide concentration of 0.4 mg·mL-1. The IC50 of Astragalus polysaccharide and oyster mushroom polysaccharide were 0.28 and 0.424 mg·mL-1, respectively. The information obtained from this work is beneficial for the use polysaccharides as a dietary supplement for health foods and therapeutics for diabetes.