Modelling and Analysis of Moisture Sorption Isotherm of Raw and Pregelatinized Rice Flour and Its Crystalline Status Prediction
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Moisture sorption behaviour of pregelatinized rice flour, in comparison to raw rice flour was studied. Empirical modelling, analysis of moisture adsorption behaviour and biophysical properties were considered to understand the mechanism of the high moisture sorption behaviour followed by the prediction of crystalline status of flour samples. Type II sorption characteristic was found for both raw and pregelatinized rice flour samples. Monolayer moisture content of 0.0581 and 0.0419 g/g (db), respectively, was obtained for raw and pregelatinized rice flour. BET surface area (S BET m2/g) of pregelatinized rice flour was found to be less than raw rice flour. Further, a single parameter empirical model was derived to explain the moisture sorption behaviour of rice flour. In the derived model, the model parameter (K) was considered as the crystalline status. Evidently, X-ray diffraction study was used as the confirmatory tool to justify the explanation given for the model term (K). Lower K value obtained for pregelatinized rice flour was indicative of lower crystalline order and higher affinity to absorb moisture. The result obtained out of this work provides a new insight into the high water sorption behaviour of pregelatinized starch. In addition, the empirical model can also be useful for prediction of crystalline status of starchy materials.
KeywordsGelatinization properties Moisture adsorption isotherm Rice flour Surface area Crystalline status
Compliance with Ethical Standards
This research was financially supported by Department of Science and Technology, Govt. of India, under INSPIRE Ph.D. fellowship (No. DST/INSPIRE Fellowship/2013/997), received by first author. First author is also thankful Dr. Vasudha Sharma for her suggestion during various stages of manuscript preparation.
Conflict of Interest
Soumya Ranjan Purohit declares that he has no conflict of interest. Dr. Pavuluri Srinivasa Rao declares that he has no conflict of interest.
This article does not contain any studies with human participants or animals performed by any of the authors.
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