梯度醇沉对拐枣多糖的理化性质及抗氧化活性的影响研究

Study on the Effects of Gradient Alcohol Precipitation on the Physicochemical Properties and Antioxidant Activity of Hovenia dulcis Polysaccharides

摘要: 本研究以拐枣肉质果梗为实验材料，通过梯度乙醇沉淀法得到拐枣多糖。采用热水浸提法获得拐枣多糖上清液，对上清液进行处理后，依次加入不同体积分数的乙醇，使其达到不同的乙醇浓度(30%、50%、和70%，v/v)，获得三种拐枣粗多糖HDPP30、HDPP50、HDPP70，研究其多糖得率、化学组成、结构表征和抗氧化生物活性，以期为进一步研究拐枣多糖的结构和功效关系奠定基础。结果表明，乙醇浓度的改变对拐枣多糖HDPP30、HDPP50、HDPP70的得率、化学组成成分含量、分子量分布、红外吸收特征峰、微观形貌均有影响，但主要结构保持不变。多糖HDPP70的得率最高，三种多糖在总糖含量、蛋白质含量、糖醛酸含量上均存在显著性差异。随着乙醇浓度的增大，提取出的多糖对自由基的清除率逐渐增大，抗氧化性生物活性逐渐增强。

Abstract: This research utilized the fleshy fruit stalks of Hovenia dulcis as experimental subjects and acquired Hovenia dulcis polysaccharides through a gradient ethanol precipitation technique. Initially, hot water extraction was employed to isolate the polysaccharide supernatant. Subsequent treatment involved the addition of ethanol at various concentrations (30%, 50%, and 70%, v/v) to yield three crude Hovenia dulcis polysaccharides termed HDPP30, HDPP50, and HDPP70. The study focused on investigating the yield, chemical composition, structural properties, and antioxidant activity of these polysaccharides, aiming to establish a groundwork for future exploration into their structural characteristics and efficacy. The findings indicated that altering the ethanol concentration influenced the yield, chemical composition, molecular weight distribution, infrared absorption features, and microscopic structure of HDPP30, HDPP50, and HDPP70, while preserving the primary structure. Notably, HDPP70 exhibited the highest polysaccharide yield, with significant variations in total sugar, protein, and uronic acid contents among the three polysaccharides. Moreover, the radical scavenging capability of the extracted polysaccharides and their antioxidant activity increased progressively with rising ethanol concentrations.