Optimization and Characterization of Pectin Extraction from Cocoa Pod Husks by Ultrasound-Assisted Enzymatic Method

Cocoa pod husk is the main byproduct of cocoa processing and is rich in pectin, holding great potential for high–value utilization. Traditional acid extraction causes severe environmental pollution, while the single enzymatic method is time–consuming, necessitating the development of a green and efficient extraction technology. In this study, an ultrasound–assisted enzymatic extraction method was employed, and the extraction process was systematically optimized via Plackett–Burman design, the steepest ascent method, and Box–Behnken response surface methodology. Under the optimized conditions, the pectin yield, galacturonic acid content, and degrees of esterification were 14.34 ± 0.39%, 67.93 ± 1.13%, and 43.62 ± 0.6%, respectively, indicating low–methoxyl pectin characteristics. Compared with literature data, the present method showed favorable performance in terms of yield, purity, extraction time, and enzyme consumption relative to conventional acid and single enzymatic extraction methods. This approach effectively couples ultrasonic cell wall disruption with specific enzymatic hydrolysis, thereby enabling efficient preparation of high–quality pectin under mild, low–energy conditions. It provides a green and highly efficient alternative for the resource utilization of cocoa pod husk waste.