Determination of Pectin in Sunflower and Its Application in Food Industry

Pectin is a complex polysaccharide consisting mainly of esterified D-galacturonic acid residues in an alpha-(1-4) chain. The acid groups along the chain are largely esterifed with methoxy groups in the natural product. It has broad applications in both food and pharmaceutical industries where it acts as gelling and thickening agent. The present study was designed to determine the galacturonic acid content and degree of pectin esterification. In the current study Record cultivar of sunflower grown in Varamin region of Iran was selected for pectin extraction. The residue was dried in a drying chamber and stored at 4°C before use. The pectin was extracted by using 0.75% sodium hexameta phosphate at the pH of 3, 4 and 5 with the temperature of 75, 85 and 95°C for 20 and 40 minutes and the optimum conditions for the extraction of pectin, galacturonic acid content and the degree of esterification was studied. The highest yield was obtained at the pH of 5 and temperature of 95°C for 20 min. Galacturonic acid content or degree of purity related to the pectin was from 66.5% to 86%. Degree of esterification of extracted pectin was from 21% to 33% that clearly indicates the low methoxyl nature of the pectin. However, there were significant differences (p<0.05) between mentioned extraction condition factors, that is an important criterion for the quality of the pectin and the degree of esterification. It seems that the pectin extracted from sunflowers head show a high potential for commercial food applications.