EXTRACTION AND CHARACTERIZATION OF PECTIN OR PECTIN SUBSTANCES FROM KINNOW PEEL AND POMACE

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Date
2013
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Punjab Agricultural University
Abstract
Pectin was extracted using water acidified with HNO3 from dried kinnow peel and pomace by varying temperature (40-80°C), time (10-90 m) and pH of solution (1.2-2.25). Pectin yield was found to be more in peel than pomace. Yield of pectin increased with increase in temperature to 60°C and pH up to 2.0 and was less at 10 and 20 m of extraction time. Temperature 60°C-80°C, time 30-90 m and pH 1.2-2.0 was selected for optimization of extraction conditions. A wide variation in yield, degree of esterification (DE), viscosity and molecular weight (MW) was observed during pectin extraction with HNO3 or HCl under different combinations of extraction conditions. Time of extraction was found to have most significant effect on yield of pectin whereas pH of extraction solvent had most significant effect on DE, viscosity and MW. In peel and pomace, optimized temperature, time and pH for pectin extraction using HNO3 were 73.41 & 69.34°C, 62.97 & 60.54 m and pH 2.0. Under these conditions pectin yield 15.4 & 6.0%, DE 90 & 90%, viscosity 0.03021 & 0.03023 pas and MW 89435.5 & 92342.2 was found in peel and pomace respectively. Using HCl optimized conditions were 75 & 73°C, 60.48 & 61.28 m and pH 2.0 which gave 15.3 & 6.1% yield, 90 & 90% DE, 0.02975 & 0.02924 pas viscosity and 76513.8 & 77915.4 MW in peel and pomace respectively. In peel and pomace, pectin yield increased with increase in time of extraction up to 5 m whereas DE, viscosity and MW increased up to 4 m with microwave assisted pectin extraction from both peel and pomace. Purification of pectin by DEAEcellulose column chromatography resulted in better color quality. Storage of peel and pomace for three months resulted in decrease in yield and physicochemical properties of pectin extracted under both ambient and refrigerated conditions. However, refrigerated storage slow down the reduction of pectin yield and quality. Our results indicated that kinnow peel and pomace are the good source of pectin. Pectin extracted with HNO3 method was having better yield and quality of pectin as compared to pectin extracted with HCl or microwave assisted HNO3 method. Peel and pomace can be stored under refrigerated conditions if storage is necessary, as degradation rate was slow at low temperature.
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application methods, inorganic
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