Moisture Adsorption and Desorption Characteristics of Wheat Flour

Abstract

Abstract: High-gluten, middle-gluten and low-gluten wheat flours were determined by static equilibrium gravimetric method for adsorption and desorption equilibrium moisture contents under different conditions of temperature (10, 20, 30 ℃ and 40 ℃) and humidity (11%—87%). Based on the obtained data, moisture adsorption isotherms were plotted and a logistic model was fitted to establish an empirical formula. Substantially the same moisture adsorption isotherms of high-gluten, middle-gluten and low-gluten wheat flours were observed as an ‘S’-shaped pattern under specific conditions. The adsorption isotherms of middle-gluten wheat four at 10, 20 ℃and 30 ℃ displayed a shift towards the bottom right of the coordinate. Middle-gluten wheat four revealed basically the same adsorption isotherm at 40 ℃ and 30 ℃. Adsorption hysteresis was observed at 10, 20 ℃ and 30 ℃ and the lower the temperature, the larger the hysteretic loop area. In contrast, hysteretic loop disappeared at 40 ℃. Therefore, a valid empirical formula of moisture adsorption isotherm for wheat flour has been developed in this study.

Key words: wheat flour, adsorption, desorption, moisture adsorption isotherm

CLC Number:

TS205
TS207

References

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