Ultrasonic-microwave assisted extraction, characterization and biological activity of pectin from jackfruit peel

Extraction and application of pectin from jackfruit (Artocarpus heterophyllus) peel could add value to the waste products arising from processing of the jackfruit. In this study, pectin from jackfruit peel was extracted using different organic acids and mineral acids. A response surface methodology was employed to optimize the ultrasonic-microwave-assisted extraction (UMAE) of pectin with citric acid. The pectins obtained from UMAE (UM-P) and conventional heating (CH-P) were compared in terms of their physicochemical and antioxidant properties. The optimum UMAE conditions were: extraction temperature 86 °C, extraction time 29 min, and solid-liquid ratio 1:48 (w/v). Under these conditions, the yield of pectin was 21.5%. Physicochemical analysis suggested that two pectins (UM-P and CH-P) were major in galactose, rhamnose, arabinose, glucose, and galacturonic acid with a high degree of methyl-esterification. UM-P and CH-P possessed considerable antioxidant activities, while UM-P had stronger antioxidant abilities than CH-P in certain tests. The current work showed that critic acid is a 'green' and safe acidic solvent that could be used to effectively extract pectin from jackfruit peel. The UMAE method is considered to be a potential alternative conventional extraction method. Pectins from jackfruit peel could potentially be used as natural antioxidants by the food industry.