Journal of food science vol:71 issue:9 pages:E370-E375
Thermal texture degradation of carrots was studied at a temperature of 100 degrees C in aqueous solutions containing sodium chloride, citric acid, ascorbic acid, and ethylenediaminetetraacetic acid (EDTA) at different concentrations. To enhance the texture of the final product, the carrot samples were pretreated, at 65 degrees C for 30-min in an aqueous calcium chloride solution (5 g/L). For all case studies considered, the pH of the solutions was adjusted to pH = 6.0. In parallel, both the changes in degree of esterification (DE) and the progress of the beta-elimination reaction of carrot pectin under the same conditions were investigated. The kinetic parameters for texture degradation (rate constant k(t) and final texture value [TP infinity/TP0]) were estimated using a fractional conversion model. The results Indicate that both the rate constant for texture degradation (k(t)) and the rate constant for the beta-elimination reaction (k(b)) increased with increasing additive concentration, while the final texture values (TP infinity/TP0) and DE decreased with increasing additive concentration in all systems studied. A high correlation was observed between the relative rate constant for texture degradation and the relative rate constant for the beta-elimination reaction on the one hand, and the relative final texture value and the relative rate constant for the beta-elimination reaction on the other hand, suggesting that the Influence of the solutes on texture degradation can be explained by their influence on the beta-elimination reaction.