Extraction of pectin from passion fruit peel assisted by ultrasound

• Ultrasound-assisted extraction is an alternative, efficient and time saving technology for pectin extraction.
• The pectin extraction by ultrasound present a GalA content higher than 65% and a DE higher than 50%.
• The optimum ultrasound extraction conditions were 85 °C and 664 W cm−2.

The effect of power intensity of ultrasound and temperature on the pectin extraction from passion fruit peel was evaluated by response surface methodology. The extraction was performed using a dried peel/extractant ratio fixed at 1:30 for 10 min of sonication. The dependent variables were the yield, the galacturonic acid content and the esterification degree of the extracted pectin. The highest yield of pectin was obtained by power intensity of 644 W/cm2 and temperature of 85 °C. Under these conditions, the yield, the galacturonic acid content and the esterification degree were 12.67%, 66.65% and 60.36%, respectively. The conventional extraction (dried peel/extractant ratio 1:30, 10 min and 85 °C) was performed to compare the results to the ultrasound-assisted extraction. The results showed that the use of ultrasound promoted a better extraction yield of pectin when compared to the conventional method.