Effect of Different Acids, Heating Time and Particle Size on Pectin Extraction from Watermelon Rinds

Abstract

Watermelon cultivation has widely been expanded in Iraq and industrial by-products like watermelon rinds play an important role in pectin manufacture. The objective of this investigation was to determine a practical follow-up to the extraction of pectin from watermelon rinds and to characterize it in a laboratory, on a small scale, aiming at establishing the optimum conditions for acid extraction. The independent variables were citric acid concentration (0.08 – 5 g/ml) and heating time (20 – 110 min). The highest yields were obtained when watermelon rinds was dried and ground to obtain a watermelon flour to be used as raw material, citric or nitric acids were used and when the citric acid concentration was (5 g/100 ml) and the time of reaction was (110 minutes). The watermelon variety in itself was not significant in pectin yield. The degree of esterification (DE = 44.37 %) of the product obtained, as well as its physical looks, show the success of pectin extraction. Results have shown that the generated model adequately explained the data variation and significantly represented the actual relationship between the independent variables and the responses, with a correlation coefficient of (0.938) and a (44.9454 %) absolute average percent error.