Microwave-assisted extraction and characterisation of pectin from pineapple biomass

Pectin is commonly used in the food and beverage industry. It is naturally found in most fruits biomass. Biomass residue from the processed-fruit industry is very potential as a source material for pectin and pectin-based products, such as residue from the pineapple industry. This study aimed to extract and characterize pectin which obtained from the pineapple waste such as pineapple peel. The method used in this study was microwave-assisted extraction (MAE). Pectin was obtained by application of citric acid solvent and precipitation of ethanol. The pectin qualification method used here was by measuring the time of cleavage of the pectate by a very pure and specific enzyme, namely pectate lyase, with spectrophotometry at a wavelength of 235 nm. The FTIR result confirmed the isolated pineapple pectin (PP) in this study substantiates the existence of galacturonic acid as the main polymer in pectin while the main peak corresponded to negative control, carrageenan (CR), as a non-pectin substance did not exist. In conclusion, higher application of citric acid solvent used in Microwave-Assisted Extraction technique has better effect in obtaining PP pectin. The highest yield of PP pectin, i.e. 0.66 g (w/w), was obtained by the MAE extraction with application of the 20% citric acid. Megazyme assay for identification of pectin has verified the presence of pectin in the extracted PP product. The finding was in line with the FTIR analysis which validated the existence of galacturonic acid as the main polymer of PP pectin. FTIR analysis indicated high methoxyl pectin compounds increased with increasing used of citric acid concentration. The identification analysis suggests potential use of pineapple peel as source material for pectin and pectin-based product. Further analysis such as optimization of extraction method and quantification of degree of esterification are imperative to be conducted in near future research.