Dragon fruit peel pectin: Microwave-assisted extraction and fuzzy assessment

Dragon fruit peels were used as a material for pectin extraction. Microwave-assisted extraction (MAE) using powers of 300, 450 or 600 W and heating times of 5 or 10 min were investigated. Compared to the conventional method, the MAE method produced a higher yield of pectin, with the highest pectin yield (23.11%) being obtained using a microwave power of 600 W and a heating time of 10 min. However, during the MAE extraction, the degradation of pectin may have occurred which resulted in a drop in viscosity. The fuzzy assessment method (FAM) was applied to determine suitable conditions for MAE. The highest overall performance index obtained from FAM indicated that a microwave power of 450 W and an extraction time of 5 min were suitable conditions to produce a high pectin quantity with less degradation. Moreover, the anhydrouronic acid content, degree of esterification and the Fourier-transform infrared spectrum of MAE pectin did not differ from the conventional pectin and therefore, the extract could be categorized as a high methoxyl pectin.