Kinetic Parameter Estimation for Quality Change during Continuous Thermal Processing of Grapefruit Juice |
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| Authors: | ELI COHEN YEHUDITH BIRK CHAIM H MANNHEIM ISRAEL S SAGUY |
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| Affiliation: | Authors Cohen, Birk, and Saguy are with the Dept. of Biochemistry, Food Science &Nutrition, Faculty of Agriculture - The Hebrew Univ. of Jerusalem, P.O. Box 12, Rehovot 76100, Israel. Author Mannheim is with the Dept. of Food Engineering &Biotechnology, Technion-Israel Institute of Technology, Haifa 32000, Israel. Address inquiries to Dr. I.S. Saguy. |
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| Abstract: | Reaction order, activation energy (Ea) and average rate constant (kav) were evaluated by dynamic modeling for color degradation of grapefruit juice during thermal processing. Simulated aseptic conditions were: 85–135°C, 40–175 set processing time, and average velocities 5–30 cm/set. Quality was assessed by nonenzymatic browning index (NEBI) and S-hydroxymethyl-furfural (HMF). Average values for reaction-order and energy of activation were: 0 and 21.4 kcal/g-mol (NEBI) and 0.3 and 23.2 kcal/g-mol (HMF), respectively. These values were compared with those contained in the deformed ellipsoid which define the 90% joint confidence interval of all possible parameter combinations. Based on initial and final concentrations, the method can predict effects of processing on liquid foods. |
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| Keywords: | grapefruit juice dynamic modeling thermal processing quality deterioration |
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