Effects of drying methods and plasticizer concentration on some physical and mechanical properties of edible chitosan films
Effects of drying methods and plasticizer concentration on some physical and mechanical properties of edible chitosan films
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DOI：
10.1016/j.jfoodeng.2010.02.025
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发表时间：
2010-07
影响因子：
5.5
通讯作者：
W. Thakhiew;S. Devahastin;S. Soponronnarit
中科院分区：
文献类型：
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作者：
W. Thakhiew;S. Devahastin;S. Soponronnarit
为了改善食用壳聚糖薄膜刚性脆的缺点，提出了采用先进的干燥方法，结合适当浓度的增塑剂来改善薄膜力学性能的想法，并进行了试验。采用热风干燥（≈40°C）、真空干燥和低压过热蒸汽干燥（90°C, 10kPa）三种干燥方法，对4种甘油浓度（0%、25%、75%和125% w/w壳聚糖）塑化制备的食用壳聚糖薄膜的物理（厚度、颜色）和力学（抗拉强度和伸长率）性能进行了研究。采用动态机械热分析（DMTA）测定玻璃化转变温度，验证壳聚糖薄膜的致密性。研究发现，干燥方式和增塑剂浓度对薄膜的干燥时间、拉伸强度、伸长率和玻璃化转变温度有显著影响。另一方面，在较低甘油浓度下，干燥方法和增塑剂浓度对薄膜样品的厚度和最终含水率没有影响。在真空干燥和LPSSD的情况下，增塑剂浓度有一个限值（25% w/w），超过该限值，增塑剂浓度对机械性能的影响可以忽略不计。在所有情况下，所有测试胶片的颜色都没有显著差异。
In order to alleviate shortcomings of edible chitosan films, which are rigid and brittle in nature, an idea of using advanced drying methods, in combination with appropriate concentration of plasticizer, to improve the mechanical properties of the films was proposed and tested. Physical (thickness and color) and mechanical (tensile strength and percent elongation) properties of edible chitosan films plasticized at four glycerol concentrations (0%, 25%, 75% and 125% w/w chitosan) and prepared by three drying methods, namely, hot air drying (≈40°C), vacuum drying and low-pressure superheated steam drying (LPSSD) (90°C, 10kPa) were investigated. Dynamic mechanical thermal analysis (DMTA) was used to determine the glass transition temperature to verify the compactness of edible chitosan films. It was found that the drying methods and plasticizer concentration significantly affected the drying time, tensile strength, percent elongation and glass transition temperature of the films. On the other hand, the drying methods and plasticizer concentration did not affect the thickness and final moisture content of the film samples at lower glycerol concentrations. In the cases of vacuum drying and LPSSD, there was a limiting value of plasticizer concentration (25% w/w) beyond which the effect of the plasticizer concentration on the mechanical properties was negligible. In all cases, the color of all tested films was not significantly different.