Investigation of yield and physicochemical properties of pectin extracted from eggplant peel

Eggplant peel contains valuable materials such as pectin which its extraction can be beneficial from economic and environmental aspects. The overall objective of this study was to evaluate the effect of three variable temperature (60, 75 and 90), time (50, 100 and 150) and pH (1.5, 2.25 and 3) on the yield, the galacturonic acid content and esterification degree of Eggplant peel pectin. Response surface methodology was used to optimize the extraction conditions. To study the physicochemical properties of the pectin, the emulsion stability during different days and at some temperatures, flow behavior at different concentrations. According to the results, the highest extraction yield of the eggplant peel was 28.30% which was observed temperature 90ᴼC, time 150min and pH 1.5. The highest galacturonic acid content of the extracted pectin of eggplant peel was 76.50%, at temperature 75ºC, time 100 min and pH 2.25, The highest esterification degree of extracted pectin of eggplant peel was 83.200%, which was observed at temperature 60ºC, time 50 min and pH 3, The results of variance analysis showed that extraction temperature was the most effective factor on the yield and esterification degree of the pectin extracted. The most emulsion stability of eggplant peel pectin was observed at 4 °C and on the first day of storage. With increasing of the concentrations of pectin samples (from 0.1% to 2%), viscosity was increased- Flow behavior of the all samples was Newtonian. Therefore, can be used of eggplant peel waste as a source of pectin.