Abstract: The adsorption isotherm of oyster products dried by freeze-drying and microwave drying equipment at 25 °C was studied by static adjustment of environmental humidity method, and the glass transition temperature was measured by differential scanner.
The results showed that the equilibrium moisture of dry oysters increased with the increase of water activity (aw), and the fitting of BET and GAB models to adsorption isotherms was very good. The effect of water as plasticizer on glass transition temperature It is obvious that the glass transition temperature decreases significantly with the increase of equilibrium water. When the dry moisture content of the oyster is 0.18 kg/kg dry basis, the products obtained by the two drying methods have a corresponding glass transition temperature of 0. Below °C.
Key words: oyster microwave drying; freeze drying; adsorption isotherm; glass transition temperature
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