Optimize the Extraction Conditions of Pectin Extracted from Saveh Pomegranate Peels

In recent years, numerous studies have been done on the beneficial use of food waste. Pomegranate is widely used in food industries, and the skin of this fruit containing the valuable substance, pectin, is discarded as waste. The general aim of this study was to investigate the effect of temperature (35, 65, and 95 ºC), time (40, 120, and 200 min), and pH (1, 2, 3) on the galacturonic acid percentage, Degree of Esterification (DE), and yield rate of pectin extracted from pomegranate peels and optimize extraction conditions. Therefore, 15 treatments were designed using the response surface methodology Box-Behnken and the obtained results were analyzed and optimized by using the response surface method at a confidence level of 95% in Minitab 16 software. The results of the analysis of variance (ANOVA) showed that the linear effect of temperature, time and pH had significantly (p ≤0.05) affected the amount of pectin extracted from pomegranate peels. Results showed that hard extraction conditions (lower pH, higher temperature, and greater time) have increased the extraction yield and the amount of galacturonic acid of pectin, while these conditions have reduced the degree of esterification of pectin. According to the results, the yield of pectin extracted from pomegranate peels, the percentage of galacturonic acid, and the degree of esterification varied from 6.96% to 8.65%, 60.31% to 84.64%, and 52.30% to 65.21%, respectively. The multiple optimum extraction conditions to achieve maximum yield of pectin extraction (8.65%) and galacturonic acid (83.49%) with 97.60% desirability were obtained at 94.39 °C, time 200 min, and pH = 1.24. The results of this study proved that pectin can be extracted from Saveh pomegranate peel with desirable quality properties and used in food formulations.