Moisture Sorption Characteristics of Starchy Products: Oat Flour and Rice Flour
2009
Brett, B. | Figueroa, M. | Sandoval, A. J. | Barreiro, J. A. | Müller, A. J.
Moisture sorption isotherms for oat flour and rice flour were determined at 5, 23, and 45 °C using a gravimetric technique in an a w range of 0.08-0.98. The results obtained showed that, for a w values lower than around 0.75, in both flours, the sorption capacity decreased with increasing temperature, while the opposite behavior was observed at a w greater than this value. It was found that the experimental data in the water activity range considered were better represented by the four-parameter Peleg equation. The monolayer water contents for both materials were determined by the BET and GAB models. The net isosteric heats of sorption were estimated using the Clausius-Clapeyron equation. For both materials, the monolayer water content and the isosteric heat of sorption were found to decrease with increasing temperature and increasing moisture content, respectively.
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