EXTRACTION AND CHARACTERIZATION OF PECTIN FROM PINEAPPLE PEELS (ANANAS CONOSUS) AND COCOA HUSK

Pineapple peels and cocoa husks are typically discarded as agricultural waste from food processing in many areas of Chiang Rai. Here, we aim to extract and characterize the pectin from the pineapple waste and cocoa husk collected in the Chiang Rai area. Pectin was initially extracted using organic solvents (hydrochloric acid and citric acid), followed by ethanol precipitation. The pectin extracted was then evaluated for its dry matter yield, equivalent weight, and degree of esterification (%DE). The results showed that the pineapple residue contained 1.50-2.97% pectin, whereas the cocoa husk contained 6.20-15.86% pectin. The gram equivalent weight of cocoa husk was approximately 800-900, while pineapple waste was 1,300. The extracted pectin displayed low methoxy content, with a low level of DE (11-22%). Finally, the functional groups of pectin extracted were confirmed by Fourier transform infrared spectroscopy, showing the existence of the –C=O and C–O stretching peaks at 1600-1700 and 1100-1200 cm-1, respectively. This preliminary study provides useful information for future studies on the gelling properties of the pectin from pineapple and cocoa husk waste.