食品科学2017，Vol.38Issue(7)：55-62,8.DOI:10.7506/spkx1002-6630-201707010
花生壳/仁的吸附等温线与热力学特性
Moisture Adsorption Isotherms and Thermodynamic Properties of Peanut Shell and Kernel
摘要
Abstract
In order to reveal the relationships between temperature and moisture content and water activity (aw) of peanut shell (PS) and peanut kernel (PK) and thus to improve the storage stability of peanut,the moisture adsorption isotherms of PS and PK were investigated at 10,20 and 30 ℃ by the static weighing method.Thermodynamic properties such as net isosteric heat of sorption (qst),differential entropy (Sd),spreading pressure,integral entropy,integral enthalpy,enthalpyentropy compensation,and glass transition temperature (Tg) of PS and PK were also discussed.The results showed that the water adsorption of PK and PS followed a typical type Ⅲ isotherm behavior,and the water contents of PK and PS increased with increasing aw.The GAB model showed the best fit with the experimental data.The qst and Sd of PS and PK decreased with increasing moisture content.The spreading pressure increased with increasing aw,and decreased with increasing temperature.The integral enthalpy decreased with increasing moisture content,whereas reverse trend was observed for the integral entropy.Both qst and Sd of PS were higher than those of PK,while the spreading pressure of PK at the same temperature was higher than that of PS.At the same moisture content,the integral enthalpy of PK was lower than that of PS,whereas integral entropy of PK was higher than that of PS.The water adsorption processes of PS and PK were both a spontaneous process driven by enthalpy and Tg of PS and PK decreased with increasing water content,with the former being higher than the latter at the same water content.According to the state diagram,at 10 ℃,critical water activity and critical water content were 0.80 and 0.175 4 g/g for PS and 0.68 and 0.095 5 g/g for PK,respectively.These results can provide a theoretical basis for peanut drying and improved storage stability of dehydrated peanut.关键词
花生/吸附等温线/热力学性质/玻璃化转变温度/状态图Key words
peanut/moisture adsorption isotherms/thermodynamic properties/glass transition temperature/state diagram分类
轻工纺织引用本文复制引用
赵亚,张平平,石启龙..花生壳/仁的吸附等温线与热力学特性[J].食品科学,2017,38(7):55-62,8.基金项目
国家自然科学基金面上项目(31171708) （31171708）
