36D-8 |
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G. CHEN1, O. H. Campanella1, C. M. Corvalan2, S. Purkayastha3, and M. Peleg4. (1) Dept. of Agricultural & Biological Engineering, Purdue Univ., 1146 Agricultural & Biological Engineering Bldg., West Lafayette, IN 47907-1146, (2) Dept. of Food Science, Purdue Univ., 745 Agriculture Mall Dr., West Lafayette, IN 47907-2009, (3) A.E. Staley Manufacturing Co., 2200 E. Eldorado St., Decatur, IL 62525, (4) Dept. of Food Science, Univ. of Massachusetts, Amherst, 228 Chenoweth Lab., Box 31410, Amherst, MA 01003-1410 Predicting how the viscosity of starch-based foods changes during thermal processing is an important aspect of engineering design and product development. Since the viscosity of starch pastes is closely related to the starch,s granules size, the latter must be known at any time during the heating process in order to predict correctly the product,s momentary viscosity. The objective of this study was to develop and validate experimentally a mathematical model to predict the momentary mean granule size of Crosslinked CornStarch (CCS) during non-isothermal heat treatments from isothermal size measurements. Swelling of CCS granules suspended in distilled water was measured at several constant temperatures between 50 and 70o C. The results were fitted with the Weibull distribution model ln(1-X(t))=-b(T)tn(T), where X is defined as (Dt-D0)/(De-D0), and Dt, D0 and De are the granules, momentary, initial and equilibrium mean diameters, respectively, t is the time, and b(T) and n(T) are the two temperature dependent parameters of the distribution. The mathematical expressions found for the temperature dependence of b(T) and n(T) were used to construct a dynamic rate model to predict the changing mean granule size during non-isothermal heating. Comparisons of the predicted changes in the granule size with those actually measured under several different non-isothermal heating regimes were in good agreement. This demonstrated that isothermal swelling data could be used to predict swelling patterns under non-isothermal conditions which are more commonly encountered in industrial processes.
Session 36D, Food Engineering: Rheology
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |