Extraction and Analysis of Pectin from Citrus Peels: Augmenting the Yield from Citrus limon Using Statistical Experimental Design

Pectin is a structural hetero polysaccharide, commonly obtained from the peels of citrus fruits and finds prime commercial use as a gelling agent and stabilizer in food industries. In the present study, pectin was extracted using alcohol precipitation method from the peels of orange (Citrus sinensis), sweet lime (Citrus limetta) and lemon (Citrus limon). When the extraction conditions were varied one-at-a-time, a maximum yield of 36.71% was obtained from C. limon, after which the yield was further enhanced using the Box-Behnken Design of Response Surface Methodology. Optimum conditions for the extraction process were established to be pH 3.5, temperature 65°C and time 67.5 min. The interaction effects of these variables were studied using 3-D and contour plots. A 1.5-fold increase in pectin yield was obtained as a result of this experimental design. Analysis of variance indicated the significance of the model. The pectin obtained was then subjected to qualitative and quantitative analyses and found to contain desirable methoxyl, hyaluronic acid contents and degree of esterification. Functional groups present in the pectin were investigated using FTIR spectroscopy. The overall results point towards the amenability of the extracted pectin for industrial applications.