Functional properties of various molecular weights and functional groups on pectin

1992财政年度取得了以下成果。制备了各种分子量和官能团的果胶。以市售高甲氧基果胶和新鲜水果为原料，采用酸脱甲基法制备果胶。我们分析了化学组成，并通过GPC测量了分子分布（取决于科学研究预算）。随着脱甲基时间的延长，甲氧基含量减少，分子量分布向低分子量侧移动.考察了阳离子对溶胶-凝胶转变过程流变性和粘度行为的影响。加入少量Ca^2+后，脱甲基果胶凝胶的形成是均匀的，但加入Mg^2+后，凝胶的形成并不均匀，因为分子的结合速度很快.采用差示扫描量热法（DSC）研究了阳离子对低甲氧基果胶溶液热性质的影响。确定了甲氧基含量的差异对凝胶的冻结峰温度、熔融峰温度和焓的影响。阐明了不同分子量的果胶和不同官能团对果胶溶胶-凝胶转变的影响.无花果多糖的功能性质：（1）影响无花果多糖水溶性组分凝胶化行为的因素;（2）无花果多糖水溶性溶胶和凝胶的流变学性质;（3）无花果多糖的质构特性。我们希望研究水在溶胶-凝胶中的行为以及各种添加剂对阳离子的影响，并在未来阐明不同分子量和官能团的果胶的功能特性。

The following results were obtained in the fiscal year1992.1. Prepared various molecular weights and functional groups of pectin. Each pectin was prepared from commercially high methoxyl pectin and fresh fruits by the acid-demethylating method. We analyzed the chemical composition, and measured the molecular distribution (dependent on the science research budget) by GPC. Then we clarified that the methoxyl groups decreased with an increase in demethylating time, and the molecular weight distribution shifted to the lower molecular weight side.2. The effect of cations on the rheological properties of the sol-gel transition process and the viscosity behavior were examined. A gel formation with demethylated pectin was appeared uniform with a slight addition of Ca^<2+,> but the behavior was not uniform when making gel with Mg^<2+> because catch of the molecules rapidly combined.3. The effect of cations on the thermal properties of various low methoxyl pectin solutions were measured by DSC. It was determined that the difference in the content of the methoxyl groups has an effect on the freezing peak temperature, the melting peak temperature and the enthalpy of gels. It was clarified that the pectins of different molecular weights and the functional groups were important in the sol-gel transition of the pectins.4. Functional propertics of polysaccharide of jelly fig. (1) Factors affecting the gelation behavior of aqueous components extracted from jelly fig. (2) Rheological properties of aqueous polysaccharide sols and gels prepared from jelly fig. (3) The texture profiles of jelly fig were examined. We want to examine the behavior of water in the sol-gel and the influence of various additions on the cations as well as clarify the functional properties of the pectins of different molecular weights and the functional groups in the future.