Extraction and Characterization of Pectin from Grapefruit Peels

Abstract

The aim of this study was to extract pectin from peel waste of variety of citrus fruit namely lemon (Citrus lemon) and to investigate the effect of processing conditions on the process of extraction. The raw material was prepared and pectin was extracted using nitric acid at three different temperatures (40 °C, 60 °C and 80 °C), and PH (1.0, 2.5 and 4.0). The experiments were carried out in water bath for two hours. Design-Expert at three-level three -factor general factorial design was applied. A total of 27 experiments were conducted for the variety at various extraction conditions. From the analysis of experimental data the interaction effects were studied and the optimal process conditions, maximizing the percentage yield were found. Using nitric acid, the yield of pectin for the variety varies from 4.69% ‐20.36%. It was also observed that with a decrease in PH the pectin yield increased. Similarly with an increase in extraction temperature, the pectin yield also increased. Maximum yield of 20.36% was obtained at PH 1.0 and temperature of 60 °C for the variety. The best condition for extraction using nitric acid was at 60 °C for 2 hours at pH 1.0. The pectin obtained from these methods was compared in terms of yield, physicochemical properties. The characterization of the extracted pectin was done by calculating the ash content, moisture content, equivalent weight, methoxyl content, anhydrouronic acid content and degree of esterification and varied from 3.08‐3.39%, 8.59‐8.62%, 312.5‐384.6%, 3.44‐4.3%, 65.31‐80.76%, 29.973‐30.23% for variety respectively.