Zhang Pingping, Zhao Ya, Zhang Xin, Zhu Lanlan, Fang Zhongxiang, Shi Qilong
School of Agricultural Engineering and Food Science, Shandong University of Technology, Xincun West Road, Zibo, Shandong 255000, China.
School of Agriculture and Food, The University of Melbourne, Parkville 3010, Australia.
Polymers (Basel). 2020 Feb 14;12(2):449. doi: 10.3390/polym12020449.
In this present study, the thermodynamic and thermal properties of glycerol and nisin-incorporated gum ghatti (GG, )-based films were determined. The films exhibited type III isotherm behaviors. Moisture content (MC) of films was increased with increasing water activity () and decreased with higher temperature. The incorporation of glycerol and nisin increased the sorption ability of GG films. The net isosteric heat of adsorption () and differential entropy () were decreased with increasing MC, showing an exponential negative correlation between them. Spreading pressure () was increased with increasing , but decreased with higher temperature. This incorporation of glycerol and nisin increased the , and of the GG films. The sorption behaviors were enthalpy-driven and non-spontaneous processes. The glass transition temperature (), critical MC and of the films were decreased, and increased respectively with the incorporation of glycerol and nisin. This work provides a theoretical basis for the application of edible films in fresh food preservation.
在本研究中，测定了甘油和含乳链菌肽的印度树胶（GG）基薄膜的热力学和热性能。这些薄膜表现出III型等温线行为。薄膜的水分含量（MC）随水分活度（）的增加而增加，随温度升高而降低。甘油和乳链菌肽的加入提高了GG薄膜的吸附能力。净等量吸附热（）和微分熵（）随MC的增加而降低，表明它们之间呈指数负相关。铺展压力（）随增加而增加，但随温度升高而降低。甘油和乳链菌肽的加入提高了GG薄膜的、和。吸附行为是焓驱动的非自发过程。随着甘油和乳链菌肽的加入，薄膜的玻璃化转变温度（）、临界MC和分别降低和升高。这项工作为可食用薄膜在新鲜食品保鲜中的应用提供了理论依据。
