Water Sorption Isotherms and Glass Transition Temperature of Freeze-dried and Microwave-dried Oysters

doi:10.7506/spkx1002-6630-201321019

Abstract

Abstract:

The water sorption isotherms of microwave-dried and freeze-dried samples of oyster at 25 ℃ were determined
by a gravimetric technique through static adjustment of environment, and the glass transition temperatures (Tg) were
measured by differential scanning calorimetry (DSC). The results indicate that the equilibrium moisture content of dried
oyster increased with increasing water activity (aW), and water sorption isotherms were fitted well with the GAB and BET
models. Water as a plasticizer exerted a substantial impact on Tg, which showed a significant reduction with increasing
equilibrium moisture content. Both dried samples containing 0.18 kg/kg water on a dry basis exhibited a Tg below 0 ℃.

Key words: oyster, freeze drying, microwave drying, water sorption isotherms, glass transition temperature

CLC Number:

TS205.9

YAN Dong-mei，HOU Jin-dong，YU Lian. Water Sorption Isotherms and Glass Transition Temperature of Freeze-dried and Microwave-dried Oysters[J]. FOOD SCIENCE, 2013, 34(21): 91-95.

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