[关键词]
[摘要]
为了解夹心海苔在贮藏期间水分活度、含水率、玻璃化转变温度与贮藏温度之间的关系,该研究探讨了夹心海苔吸附等温线和玻璃化转变曲线并用数学模型进行拟合,分析夹心海苔绝对安全含水率和临界含水量,并探讨热力学性质。结果表明:GAB模型能较好地反映出夹心海苔水分吸附特性,并得出在20、30、40 ℃条件下夹心海苔的绝对安全含水率分别为5.19%、4.69%、3.72%,作为预测夹心海苔加工及贮藏过程中最佳含水率的依据;同理可得20、30、40 ℃的临界含水量分别为0.98、0.84、0.71 g/g,作为判断贮藏稳定性的依据。当夹心海苔的平衡含水率高于0.08%时,水同物质的结合能较小,易失水。夹心海苔水分吸附过程中等温速率为0.62 K,吉布斯自由能为2.61 kJ/mol,为一种熵驱动的自发的吸热过程。综合分析,随着温度降低夹心海苔安全含水率升高,不易使玻璃化结构发生崩塌,对其加工工艺及干制品贮藏等方面具一定的参考意义,该研究结果可为夹心海苔产业提供科学依据。
[Key word]
[Abstract]
In order to understand the relationship among the water activity, moisture content, glass transition temperature and storage temperature of sandwich seaweed during storage, the adsorption isotherm and glass transition curves of sandwich seaweed were studied and fitted with a mathematical model. The absolute safe moisture content and critical moisture content of sandwich seaweed, and the thermodynamic properties, were discussed. The results showed that the GAB model could better reflect the moisture adsorption characteristics of the sandwich seaweed, and the absolute safe moisture contents of the sandwich seaweed at 20, 30 and 40 ℃were 5.19%, 4.69% and 3.72%, respectively, which could be used as the basis for predicting the optimal moisture content during the processing and storage of sandwich seaweed; In the same way, the critical moisture contents at 20, 30 and 40 ℃were 0.98, 0.84 and 0.71 g/g, respectively, which could be used as a basis for assessing the storage stability. When the equilibrium moisture content of the sandwich seaweed was higher than 0.08%, the binding energy of water and the substance was small, and water loss occurred easily. The water adsorption process of sandwich seaweed had an isothermal rate of 0.62 K and a Gibbs free energy of 2.61 kJ/mol, which was an entropy-driven spontaneous endothermic process. Comprehensive analysis showed that as the temperature decreased, the safe moisture content of the sandwich seaweed increased, and the vitrified structure was easy to collapse, which provided certain significant reference for its processing technology and dry product storage. The research results can provide a scientific basis for the sandwich seaweed industry.
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[基金项目]
江苏省农业科技自主创新资金(CX(19)3076)