EXTRACTION AND EVALUATION OF PECTIN FROM SUNFLOWER HEAD RESIDUE USING ULTRASONIC

Abstract

Sunflower heads remaining after seed removal are a potential source of low-methoxyl pectin (35% dry weight basis). Ultrasonic was used during extraction of pectin from alcohol insoluble solids of sunflower heads using 0.75% sodium hexametaphosphate (1:20, w:v). The extraction was carried out using different ultrasonic power levels (20, 40, 60 and 80% of maximal power) at 70, 80 and 90 o C for 15, 30 and 60 min. The obtained pectin was physically and chemically evaluated compared with commercial citrus low methoxyl pectin type 104 A/S of Hercules Copenhagen. The highest yield (23.20%) and recovery (66.4%) of pectin were obtained by using ultrasonic at 60% power at 80 o C for 15 min of extraction. These selected conditions yielded pectin with methoxyl content and degree of esterification of 4.55 and 31.97%, respectively. On the other hand, viscosity, gel strength, setting temperature and setting time of this pectin representing 80% of those of the commercial citrus low methoxyl pectin. Results showed that viscosity of the extracted pectin was gradually decreased with the increase of ultrasonic power, extraction temperature and extraction time.