Thermal Degradation Kinetics of Carotenoids in a Cashew Apple Juice Model and its Impact on the System Color

L. Q. ZEPKA; C. D. BORSARELLI; M.A.A.P. DA SILVA; A. Z. MERCADANTE

JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY

American Chemical Society

Año: 2009

0021-8561

The thermal degradation kinetics of the main carotenoids of cashew apple in a juice model system was studied and related to the changes of its CIELAB color parameters. Similar isomerization equilibrium constants and activation energies were operating for both all-trans-b-carotene and all-trans-b-cryptoxanthin. The curves for the decay of the main carotenoids and color changes showed a biphasic behaviour that was best fitted by a bi-exponential equation. For the same heating conditions (60 or 90 oC), similar rate constants for the fast (g1) and slow (g2) decays were obtained for both the chemical (carotenoids) and the physical (color) parameters monitored in the present research. This fact indicates that color parameters, such as (DE*), are good predictors of both all-trans-b-cryptoxanthin and all-trans-b-carotene thermal degradation. A mechanism for thermal carotenoid degradation was proposed, involving parallel irreversible and reversible coupled degradation reactions of both the initial all-trans-b-cryptoxanthin and all-trans-b-carotene to yield, respectively, oxidation and/or breakdown compounds and mono-cis isomers.