Effect of variety and acid washing method on extraction yield and quality of sunflower head pectin

Sunflower samples, Helianthus annuus L., of three varieties, Armavirsky, Zaria and Record, were obtained from Iran. Samples were dried and ground by hammer mill to pass a 60-mesh size screen and stored until used. Insoluble pectins were extracted from the residue with 0.75% sodium hexametaphosphate solutions at 65 degreesC and pH of 5 for 20 min. Extraction yields of pectin from the head residues were 10.67, 11.53 and 10.93%, respectively. The data were analyzed by statistical analysis. Based on the quality, the Record variety was selected for its highest methoxyl, lowest ash and highest galacturonic acid content. Pectin was washed with HCl and HNO(3) (0.1, 0.6 and 1.2 N) for 10, 20 and 30 min. Statistical analysis revealed that washing in 0.6 N HNO(3) for 10 min yielded a good quality pectin. (C) 2003 Published by Elsevier Ltd.