Extraction of Pectin from Watermelon Rind

Abstract

Watermelon rind pectin extraction was investigated using acid and enzymatic extractions. The objectives were to optimize acid and enzyme extraction procedures for highest obtainable yield and quality. Acid extraction was conducted using nitric acid and precipitated with isopropanol. Extraction conditions of 45 minutes, pH 1.65, 95˚C, and 0.258 g/mL solid to liquid ratio resulted in a pectin yield of 20.2%. Enzymatic extractions were conducted using CelluPract, Fibrilase, and Multifect XL enzymes at extraction conditions of 50˚C, 0.18 g peel/mL, 50 mM citrate buffer. Extraction time and pH were 2 hours and 4.0, 15 hours and 4.5, and 15 hours and 4.7 for CelluPract, Fibrilase, and Multifect XL, respectively. Pectin yields were 34.1, 18.7, and 18.0% for CelluPract, Fibrilase, and Multifect XL, respectively. Galacturonic acid content was 69, 47, 56, and 60% for acid, CelluPract, Fibrilase, and Multifect XL extracted pectin. All extractions resulted in low methoxyl pectins.