Kinetics of Chlorophyll Degradation in Malabar Spinach (Basellae alba) and Waterleaf (Talinum triangulare) during Hydrothermal Processing

Abstract

Hydrothermal processing of vegetables often results in a number of changes including degradation of chlorophyll, the green plant pigment that is considered to be of therapeutic benefits. This study was aimed at investigating the kinetic degradation of chlorophyll in Malabar spinach (Basella alba) and waterleaf (Talinum triangulare) during hydrothermal processing. Freshly harvested leafy vegetables-- Malabar spinach and waterleaf, were obtained and subjected to various hydrothermal conditions (60, 65, 70, 75 and 80˚C at 0, 5, 10, 15 and 20 minutes) simulating typical cooking conditions. The chlorophyll of the crushed leaf was extracted using acetone. Changes in chlorophyll was determined using spectrophotometric analysis and the kinetics of degradation for each of the vegetables were determined at varying temperatures and times. Kinetics analysis revealed that the degradation of chlorophyll in Malabar spinach and waterleaf followed the first order reaction. The rate constant obtained from the kinetic analysis provided insights into the reaction rates and allowed for the prediction of chlorophyll degradation during hydrothermal processing. The results showed that the lowest percentage decrease in chlorophyll concentration during the blanching process was obtained at 65˚C for 5 minutes for Malabar spinach and for waterleaf at 60˚C for 5 minutes. Blanching temperature and time have significant effects on degradation of chlorophyll of Malabar spinach and waterleaf which could consequently determine the economic value and overall degree of acceptability of the green leafy vegetables. The findings provide baseline against which future work can be compared and importance of maintaining quality of the vegetables during processing.