Moisture Sorption Isotherm and Glass Transition Temperature of Date Powder in Terms of Various Model Systems

作者：Sadeghi M^*; Mehryar E; Razavi J; Mireei S A

来源：Journal of Food Process Engineering, 2016, 39(1): 61-68.

DOI：10.1111/jfpe.12199

In this study, water sorption isotherm for date powder of Istameran variety was obtained using static gravimetric method. Guggenheim, Anderson and de Boer model was adequately fitted to the whole range of water activities and the model parameters were estimated within a reasonable range. The monolayer moisture contents for Brunauer, Emmett and Teller model and Guggenheim, Anderson and de Boer model were obtained to be 3.97 and 0.147g(water)/g(dry solids), respectively. The modeling procedure for predicting T-g was performed using various model systems including water as well as fructose and glucose as the major sugars found in Istameran. Brostow etal.'s model based on WFG with an even ratio of glucose and fructose showed the best prediction. Moreover, for modeling T-g as a function of A(w), Roos model indicated an acceptable fitting. By increasing the water mass fraction from 0.006 to 0.214, T-g of the samples decreased linearly from 21.5 to -65.7C. The use of the multicomponent mixtures and modeling procedure held a rational approach for theoretical determination of T-g of date powder as a function of water mass fraction as well as A(w).
Practical ApplicationsThe present study would be economically advantageous as it explains water sorption isotherm and various model systems for predicting and modeling glass transition temperature for Istameran date powder as one of the most important commercial date varieties. The powder is produced from secondary quality dates. The results are applicable by date powder producing industries during processing and storage for controlling the stickiness.

• 出版日期2016-2