Optimization of Ultrasound-Assisted Pectin Extraction from Durian Rind

Durian (Durio zibethinus) rind is fruit waste and can be used as a source of pectin. This study aimed to optimize the pectin extraction process using the ultrasound-assisted extraction (UAE) method and evaluate its physicochemical properties. Initially, influencing factors in UAE, such as solvent type (HCl, citric acid, acetic acid, and n-hexane), extraction time (10, 15, 20, 25, and 30 minutes), extraction temperature (40, 50, 60, 70, and 80◦C), sample:solvent ratio (1: 14, 1: 17, 1: 20, 1: 23, and 1: 26 g/mL), duty of cycle (20, 40, 60, 80, and 100), and amplitude (20, 40, 60, 80, and 100) were evaluated. Using central composite design (CCD), a temperature of 74◦C and sample:solvent ratio of 1: 20 g/mL were determined as optimum conditions with an estimated pectin yield of 6.07. This value is in accordance with the experimental result of 6.12. Extraction with UAE resulted in a higher pectin yield compared to the conventional extraction method using a water bath shaker. The pectin had a degree of esterification (DE) of 44.35, a moisture content of 4.34, and an ash content of 1.08. The FTIR spectra proved the presence of functional groups in pectin, the XRD patterns suggested the structure was more amorphous than crystalline, and SEM showed a smooth pectin surface. © The Author(’s).