Microwave-assisted extraction and characterization of pectin from citrus fruit wastes for commercial application

Pectin is an essential hydrocolloid widely used as a gelling, thickening, and stabilizing agent in the food, pharmaceutical, and cosmetic industry. In the present study, an effort has been made to extract pectin from Pomelo (Citrus maxima), Kinnow mandarin (Citrus reticulata) and Citron (Citrus medica) peels with microwave-assisted extraction (MAE) technique using organic citric acid. Pectin extracted with MAE was characterized in terms of yield, ash content, pH, solubility, equivalent weight, methoxyl content, anhydrouronic acid content, and degree of esterification. The extraction conditions had significant effects on physicochemical properties. The results showed that the highest amount of pectin (24.19±0.26%) was obtained from Citrus maxima. Based on DE value all pectins were categorized as low methoxy pectin (LMF). Extracted pectins were highly pure based on AUA content. Structural characterization of extracted pectin from three fruit peels by Fourier Transform Infrared (FT-IR) spectroscopy revealed that pectin has functional groups within the 1740–800 cm-1 spectral region. However, pectin extracted in this study can be used in the manufacturing of low sugar foods such as diet jams and jellies.