Effects of different microwave intensity on the extraction yield and physicochemical properties of pectin from dragon fruit (Hylocereus polyrhizus) peels

In this experiment, microwave-assisted extraction (MAE) was applied at different intensity of 300, 450, 600, and 800 W to extract pectin from dragon fruit peels. The microwave-assisted extraction was optimized using a central composite experimental design. The optimal extraction condition was established to be pH 2.07, extraction time of 65 s, and solid-to-liquid ratio of 66.57. The maxima extraction yields at 300, 450, 600, and 800 W were 11.8, 14.9, 17.2 and 18.5%, respectively. Experimental and predicted extraction yields obtained at the different microwave power levels were fitted to second-order response surface model. Microwave-assisted extraction process is effective in obtaining high-quality dragon fruit peel pectin, i.e. GalA content: 59.73–69.68%, DE value: 45.82–46.95%, crystallinity: 15.32–21.22%