Optimization of ultrasound assisted extraction of pectin from custard apple peel: Potential and new source

Pectin was extracted from the waste custard apple peel using ultrasound technique and optimized the extraction process by RSM. The various significant process parameters such as liquid-solid ratio, ultra-sonication time, temperature and pH of solution were studied in the range of 10-25 mL g^-1, 10-30 min, 50-80 °C, and 1-3, respectively. The maximum yield of pectin (8.93%) was attained at the optimum condition of 23.52 mL g^-1 of liquid-solid ratio, 18.04  min of ultra-sonication time, 63.22 °C of temperature and 2.3 pH of solution. The extracted and commercially available fresh pectin (for comparison purposes) were characterized by various analytical techniques namely, FTIR, DSC, XRD, SEM, and NMR to evaluate their functional groups, thermal properties, crystallinities, morphological and structural characteristics, respectively. The extracted pectin was a toxic free compound as determined by its anti nutritional property study and about 20 mg/mL of antioxidant presented in it.