在不存在和存在单价离子的情况下对酸性果胶样品的流变性进行表征。

Rheological characterization of acid pectin samples in the absence and presence of monovalent ions.

机构信息

Applied Chemistry, Department of Chemical and Biological Engineering, Chalmers University of Technology, 412 96 Göteborg, Sweden; SuMo BIOMATERIALS, VINN Excellence Center, Chalmers University of Technology, 412 96 Göteborg, Sweden.

Department of Structure and Material Design, The Swedish Institute for Food and Biotechnology, SIK, Göteborg, Sweden.

出版信息

Carbohydr Polym. 2014 Nov 26;113:336-43. doi: 10.1016/j.carbpol.2014.06.090. Epub 2014 Jul 17.

DOI:10.1016/j.carbpol.2014.06.090

PMID:25256492

Abstract

Pectins are traditionally divided into two groups, high methoxy and low methoxy. The groupings determine the charge of the pectin and the gelation mechanism. However, not as yet extensively studied is the impact on gelation of the distribution of the charges as characterized by an absolute degree of blockiness (DBabs). The aim of this study was to characterize rheologically the acid gelation of a pectin with a high DBabs and a degree of methyl esterification of ∼ 37%, in the absence and presence of monovalent ions. The results obtained suggest that a pectin with a blocky charge distribution at pH conditions close to or below the pKa exhibits weak gel-like properties at intermediate frequencies, despite the absence of a permanent network structure. The addition of monovalent ions changed the rheological behavior to resemble that of a strong gel whose properties depended on the type and concentration of the ions.

摘要

果胶通常分为两类，高甲氧基果胶和低甲氧基果胶。分类依据是果胶的电荷和胶凝机制。然而，电荷分布对胶凝的影响（用绝对程度的不饱和度（DBabs）来描述）尚未得到广泛研究。本研究的目的是在不存在和存在单价离子的情况下，用流变学方法表征具有高 DBabs 和甲酯化度约为 37%的果胶的酸胶凝作用。结果表明，在接近或低于 pKa 的 pH 条件下，具有块状电荷分布的果胶在中等频率下表现出弱凝胶状特性，尽管不存在永久网络结构。单价离子的加入改变了流变行为，使其类似于具有强凝胶性质的物质，其性质取决于离子的类型和浓度。