Ultrasonic extraction of pectin from Opuntia ficus indica cladodes after mucilage removal: Optimization of experimental conditions and evaluation of chemical and functional properties.

Ultrasonic assisted extraction (UAE) of pectin from Opuntia ficus indica (OFI) cladodes after mucilage removal was attempted using the response surface methodology. The process variables were optimized by the isovariant central composite design in order to improve the pectin extraction yield. The optimum condition obtained was: sonication time 70 min, temperature 70 °C, pH 1.5 and the water-material ratio 30 ml/g. This condition was validated and the performance of experimental extraction was 18.14% ± 1.41%, which was closely linked to the predicted value (19.06%). Thus, UAE present a promising alternative to conventional extraction process thanks to its high efficiency which was achieved in less time and at lower temperatures. The pectin extracted by UAE from OFI cladodes (UAEPC) has a low degree of esterification, high uronic acid content, important functional properties and good anti-radical activity. These results are in favor of the use of UAEPC as potential additive in food industry.