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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 Ascorbic acid Dehydroascorbic acid Thermal treatment kinetics Modeling
Pedagogical Context
Citation
VIEIRA, Margarida C.; TEIXEIRA, A. A.; SILVA, C. L. M. - Mathematical modeling of the thermal degradation kinetics of vitamin C in cupuaƧu (Theobroma grandiflorum) nectar. Journal of Food Engineering.ISSN 0260-8774. Vol. 43 (2000), p. 1-7
Publisher
Elsevier