食品与发酵工业2018，Vol.44Issue(2)：247-255,9.DOI:10.13995/j.cnki.11-1802/ts.014683
干燥方式对桑葚粉热力学特性与贮藏稳定性影响
Effects of drying methods on the thermodynamic properties and storage stability of mulberry powders
摘要
Abstract
The effects of spray drying and freeze drying on adsorption isotherms and thermodynamic properties of mulberry powders were investigated.The effects of two drying methods on glass transition temperature (Tg) and storage stability of mulberry powders were also compared and discussed.The results showed that the adsorption behaviors of mulberry powders followed type Ⅲ isotherms.Blahovec-Yanniotis model is the best fit to describe the absorption behaviors of mulberry powders.The net isosteric heating and differential entropy of mulberry powders decreased with moisture content increase,and then kept at the constant gradually.The spreading pressure of mulberry powders decreased with the increase of temperature,but increased with water activity (aw) increase.The integral enthalpy of mulberry powders decreased with increasing moisture content and remained at constant gradually.The integral entropy of mulberry powders decreased first (reached the minimum) and then increased rapidly with the increase of moisture content and then tended to be stable.The moisture adsorption of mulberry powders followed the enthalpy entropy complementary theory and the process was enthalpy driven and non spontaneous process.When the moisture content/aw is at the same value,the net isosteric heat,differential entropy and entropy integral of spray-dried powders were higher than those of freeze-dried ones,but the integral enthalpy of spray-dried powders was lower than that of freeze-dried ones.The Tg of mulberry powders decreased with increasing moisture content.When the moisture content is the same,Tg of freeze-dried powders was higher than spray-dried ones.At 25 ℃,critical water activity of spray-dried and freeze-dried powders were 0.095 2 and O.115 1,respectively.The critical moisture content of spray-dried and freezedried powders was 0.076 1 g/g and 0.079 2 g/g,respectively.关键词
喷雾干燥/冷冻干燥/热力学性质/贮藏稳定性Key words
mulberry/spray drying/freeze drying/thermodynamic properties/storage stability引用本文复制引用
王瑞颖,赵亚,石启龙..干燥方式对桑葚粉热力学特性与贮藏稳定性影响[J].食品与发酵工业,2018,44(2):247-255,9.基金项目
国家自然科学基金资助项目(31171708) （31171708）
