Water adsorption isotherms of carboxymethyl cellulose, guar, locust bean, tragacanth and xanthan gums

被引：112

作者：

Torres, Maria D. ^{[1
]}

Moreira, Ramon ^{[1
]}

Chenlo, Francisco ^{[1
]}

Vazquez, Maria J. ^{[2
]}

机构：

[1] Univ Santiago de Compostela, Escola Tecn Super Enxenaria, Dept Enxenaria Quim, Santiago De Compostela 15782, Spain

[2] Univ Santiago de Compostela, Fac Ciencias, Dept Enxenaria Quim, Lugo 27002, Spain

来源：

CARBOHYDRATE POLYMERS | 2012年 / 89卷 / 02期

关键词：

Water activity; Thermodynamics; Storage conditions; GAB model; MOISTURE SORPTION; THERMODYNAMIC PROPERTIES; HYDRATION;

D O I：

10.1016/j.carbpol.2012.03.055

中图分类号：

O69 [应用化学];

学科分类号：

081704 ;

摘要：

Water adsorption isotherms of carboxymethyl cellulose (CMC), guar gum (GG), locust bean gum (LBG), tragacanth gum (TG) and xanthan gum (XG) were determined at different temperatures (20, 35, 50, and 65 degrees C) using a gravimetric method. Several saturated salt solutions were selected to obtain different water activities in the range from 0.09 to 0.91. Water adsorption isotherms of tested hydrocolloids were classified like type II isotherms. In all cases, equilibrium moisture content decreased with increasing temperature at each water activity value. Three-parameter Guggenheim-Anderson-de Boer (GAB) model was employed to fit the experimental data in the water activity range and statistical analysis indicated that this model gave satisfactory results. CMC and GG were the most and the least hygroscopic gums, respectively. Sorption heats decreased with increasing moisture content. Monolayer moisture content evaluated with GAB model was consistent with equilibrium conditions of maximum stability calculated from thermodynamic analysis of net integral entropy. Values of equilibrium relative humidity at 20 degrees C are proposed to storage adequately the tested gums. (C) 2012 Elsevier Ltd. All rights reserved.

引用

页码：592 / 598

页数：7

共 37 条

[1] Water sorption isotherms of starch powders - Part 1: mathematical description of experimental data [J].