Effect of Aloe Vera Gel-Carboxymethyl Cellulose Composite Coating on the Degradation Kinetics of Cucumber

Abstract

This study aimed to investigate the effect of Aloe vera (AV) gel and carboxymethyl cellulose (CMC) composite edible coating on the postharvest quality and degradation kinetics of stored cucumbers. Control, 20%, 30%, and 50% (V/V) AV + 1% (W/V) CMC coating formulations were prepared and tested as postharvest treatments on cucumbers stored at 15 °C and 23 °C. Quality parameters such as weight, firmness, color, pH, TSS, TA, and mold count were monitored at regular intervals until day 20. The degradation kinetics of stored cucumbers, namely weight loss, firmness, and color changes, and the effect of coating treatment on the degradation kinetics were studied by fitting kinetic models to the specified experimental data. Pearson’s correlation was applied to verify the correlation among the color parameters L*, a*, and b*. Based on the interactive effects of coating treatment, temperature, and storage time, 30% AV + 1% CMC-coated cucumbers retained the most postharvest quality parameters. Overall, the first-order kinetic model fitted well with the weight loss, firmness, and color change data with a reasonably high coefficient of determination (R2) values (0.66–0.99). Both weight and firmness loss were described well by the first-order kinetic model through linear regression; however, color changes were best explained through the non-linear regression method. Moreover, the color parameters L*, a*, and b* had significant correlations that were revealed through Pearson’s correlation. The Arrhenius equation was used to study the effect of temperature on the kinetic parameters, k and Ea. Temperature increment resulted in the acceleration of the degradation process which was reflected by the higher rate constants (k) at 23 °C. From the kinetic study, 30% AV + 1% CMC coating had the most reduced degradation rate among the treatments studied. Cucumbers coated with 30% AV + 1% CMC could be stored at 15 °C for 20 days while overall postharvest quality being maintained.