Vitae (May 2009)
EVALUATION OF PECTIN SOLUBILIZATION CAPABILITY FROM LEMON PEEL USING PROTOPECTINASE-SE
Abstract
Pectin is a polysaccharide of vegetal origin widely used in food and pharmaceutical industries, among others, due to its particular physicochemical properties. Pectin solubilizing activity of Protopectinase- SE, an enzyme produced by the yeast-like fungus Geotrichum klebahnii, was studied using lemon albedo (the inner white and spongy part of the peel) and protopectin (the water insoluble pectic substance obtained from the same tissue) as substrates. Effects of substrate particle size and composition, pH and temperature of reaction medium were evaluated using a Doehlert experimental design with response surface. Temperature, pH and buffer (citric acid-sodium citrate, CitB) concentration display an important effect on pectin solubilization process, with optimal solubilization conditions at pH 5.0, 37°C and CitB = 25 mM. Yield of 37 and 28 g of pectin/100 g tissue (dry basis) are achieved under optimal reaction conditions from protopectin and albedo, respectively. In both cases, extracted pectin shows a 60% uronic acid content and 78% esterification grade
