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Mathematical-modeling of the thermal-degradation kinetics of vitamin-c In cupuaƧu (theobroma-grandiflorum) nectar
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Advisor(s)
Abstract(s)
The thermal degradation kinetics of both components of vitamin C, ascorbic acid (AA) and dehydroascorbic acid (DHAA), were determined in a nectar of CupuacĆu (Theobroma grandiĀÆorum) with 25% of pulp and 15% of sugar in water. AA was assayed by HPLC and the results showed that AA degraded into DHAA. A reversible Ā®rst order model described well the AA degradation data, with an activation energy of 74 5 kJ/mol and k80 C 0:032 0:003min Ćæ1. DHAA kinetic behavior suggested a consecutive Ā®rst order reaction where DHAA was the intermediate product of AA degradation. A mechanistic model was derived to predict DHAA concentration. Rate constants were replaced by the Arrhenius equation in the model to evaluate the temperature dependence and the kinetic parameters for AA degradation, previously determined, were used. An activation energy of 65 9 kJ/mol and a k80 C of 0:013 0:003 min Ćæ1 were estimated. The present Ā®ndings will help to predict the best CupuacĆu nectar processing conditions that minimize degradation of an important quality factor such as vitamin C.
Description
Keywords
CupuaƧu Vitamin C Thermal processing PEIE Method
Citation
MMC Vieira; Teixeira,A. A.; Silva,C. L. M.Mathematical-Modeling of The Thermal-Degradation Kinetics of Vitamin-C In Cupuacu (theobroma-Grandiflorum) Nectar, JOURNAL OF FOOD ENGINEERING, 43, 1-7, 2000.
Publisher
Elsevier