芡实皮渣多糖的提取工艺优化及体外抗氧化活性研究

为了实现芡实加工副产物资源的高值化利用,优化芡实皮渣多糖的提取工艺参数,分析其理化性质,初步研究多糖的体外抗氧化活性。在单因素实验基础上,选择料液比、提取温度、提取时间、醇沉浓度为自变量,多糖得率为因变量,通过L₉(3⁴)正交试验法优化芡实皮渣多糖的提取工艺。利用5种体外抗氧化活性测试方法,即总还原力,清除羟自由基、DPPH自由基、超氧阴离子和亚硝酸盐,并与抗坏血酸进行对比,评价芡实皮渣多糖的抗氧化能力。结果表明:芡实皮渣多糖最佳提取工艺为料液比1:40、浸提温度55 ℃、浸提40 min、醇沉浓度80%,提取3次,得率45.94%,纯度82.67%。碘-碘化钾反应显示其属于非淀粉类多糖,HPLC分析显示该多糖的基本结构单元为葡萄糖。吸水性和吸油分别为(65.15±1.52)和(1.27±0.04) g/g,多糖凝胶质构特性结果显示其黏性很大,弹性较低,回复能力弱。多糖对羟基自由基、DPPH自由基、超氧阴离子和亚硝酸盐具有一定的清除能力,当芡实皮渣多糖浓度为1.0 mg/mL时,对羟基自由基、超氧离子和亚硝酸盐的清除率分别为35.56%、34.88%和20.63%,对DPPH自由基清除率IC₅₀为(0.307±0.008) mg/mL;本研究优选的芡实皮渣多糖提取工艺稳定可靠,多糖具有一定的抗氧化能力,实验结果可为芡实加工副产物资源的综合开发利用提供理论基础。

Optimization Extraction Process of Polysaccharide from the Pericarp Residues of Euryale ferox and Its Antioxidant Activity in Vitro

In order to realize the high value utilization of the by-products from the processing of Euryale ferox, the optimal extraction technology parameters of polysaccharides from the pericarp residue of Euryale ferox were obtained, the physical and chemical properties were analyzed, and the antioxidant activity of polysaccharides was preliminary studied by the in vitro scavenging free radical test. Based on the single factor tests, the material-liquid ratio, extraction temperature, extraction time, and alcohol concentration were selected as independent variables, and the polysaccharide yield was the dependent variable. The L₉ (34) orthogonal test method was used to optimize the extraction process of polysaccharides. Using five antioxidant activity test methods in vitro, namely total reducing power, scavenging hydroxyl free radicals, DPPH free radicals, superoxide anion and nitrites, and comparing them with ascorbic acid, the antioxidant properties of polysaccharides were evaluated ability. The results showed that the optimal extraction process was a ratio of material to liquid of 1:40, an extraction temperature of 55℃, extraction 40 min, alcohol precipitation concentration 80%, and three extractions with an extraction rate of 45.94%and a purity of 82.67%. The iodine-potassium iodide reaction showed that the polysaccharide was a non-starch polysaccharide, and HPLC analysis of the hydrolysate showed that its basic structural unit was glucose. The water absorption and oil absorption of polysaccharides were (65.15±1.52) and (1.27±0.04) g/g respectively. The texture properties of the polysaccharide gel showed that it had great viscosity, low elasticity and weak recovery ability. The polysaccharides had good scavenging ability to hydroxyl free radicals, DPPH free radicals, superoxide ions and nitrites. When the concentration of polysaccharides was 1.0 mg/mL, the scavenging rates for hydroxyl free radicals, superoxide ions and nitrite were 35.56%, 34.88% and 20.63%, respectively, and the IC₅₀ for DPPH free radical scavenging rate was (0.307±0.008) mg/mL. The optimal extraction process of polysaccharides from the Euryale ferox pericarp residues were stable and reliable, and the polysaccharides had certain antioxidant capacity. The test results would provide theoretical basis for the comprehensive development and utilization of the processing by-product resources of Euryale ferox.