海藻酸钠/PE膜的制备及其保鲜和降解性能研究

摘  要

本文以LDPE为基材，选择海藻酸钠为填充剂，针对改善薄膜的保鲜和降解性能，制备不同添加量的海藻酸钠填充膜。根据薄膜的拉伸强度、断裂伸长率、透氧率和透湿量，分析不同添加量的海藻酸钠对薄膜基本性能的影响。利用所制保鲜膜对秀珍菇进行自发气调包装，通过测定秀珍菇的失重率、感官评分研究不同添加量的海藻酸钠对秀珍菇保鲜效果的影响。利用所制的薄膜进行降解实验，通过测定薄膜的失重率、拉伸强度和断裂伸长率研究不同添加量的海藻酸钠对降解性能的影响。
结果表明：随着海藻酸钠添加量的增加，薄膜的拉伸强度和断裂伸长率逐渐降低，其透氧率和透湿量在空白膜的基础上有较大改善；通过保鲜试验对秀珍菇进行失重率、感官评分的测定，表明填充膜对秀珍菇的保鲜效果优于空白膜和未包装组，其中以添加量为16.0%的海藻酸钠填充膜包装的秀珍菇的保鲜效果最好，其包装的秀珍菇感官评分最高，第14天的失重率为5.1%，冷藏下可保鲜14天，比未包装的对照组延长了8天。通过降解实验对薄膜进行失重率、拉伸强度和断裂伸长率的测定，表明海藻酸钠的填充改善了PE膜的降解性能。

关键词：保鲜膜，降解塑料，海藻酸钠，秀珍菇

ABSTRACT
                              
In this paper, LDPE material was used as a substrate and the sodium alginate as filler to improve the gas and vapor transmission rate of PE film. Various properties of sodium alginate filler films were prepared, such as tensile strength, elongation at break, gas permeability and vapor permeability were used for analyzing the effect of different content on fundamental characteristics of the filler films. These films were used to package pleurotus geesteranus for examining fresh-keeping performance. The percentage of weight-loss ratio, organoleptic test of the pleurotus geesteranus were examined, which were used to investigate the effect of the film′s function on fresh-keeping of pleurotus geesteranus, and they also used to degradation experiment for evaluating weight-loss ratio, tensile strength, elongation at break of the films, which were used to investigate the effect on the degradability.
The results showed that as the amounts of sodium alginate increased, the gas permeation rate and vapor permeation of the films increased gradually. The mechanical of the films with sodium alginate were lower than PE films. By testing the percentage of weight-loss ratio, organoleptic test of the pleurotus geesteranus, it was indicated that the films with sodium alginate were better than PE film and unpackaged control group on preservation of pleurotus geesteranus, and the film′s sodium alginate content of 16.0% is the best percent for refreshment. 14 days later the percentage of weight-loss ratio of pleurotus geesteranus with packing amounts to 5.1%, the pleurotus geesteranus under the refrigeration could keep fresh for 14 days, which was 8 days longer than the control group. By testing the weight-loss ratio, tensile strength, elongation at break of the films in degradation test, it was indicated that the filler of sodium alginate improved the degradability of PE film.

Keywords: fresh-keeping film, degradable plastic, sodium alginate, pleurotus geesteranus
 

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