Extraction of pectin from shaddock peel by microwave heating

Pectin was extracted from the fresh shaddock peel by the method of microwave heating, and the content of pectin in the extracting solution of fresh shaddock peel was determined by the method of carbazole spectrophotometric. The effects of such factors as the ratio of material to solvent, microwave output power, microwave heating time and the condition of salting-out on the extraction yield and its galacturonic acid. The orthogonal test design L9(34) was used to optimize the conditions of extraction. The results show that the microwave output power has significant effect on the extraction yield of pectin. Microwave heating time has little effect on the extraction yield of pectin. The optimum conditions are as follows: the ratio of water to material 8︰1 at pH 2.0, microwave output power 640 W, treatment time 8 min, ratio of saturated aluminum sulfate to acid hydrolysis extraction solution 3︰5. Under the optimized extraction conditions, the pectin yield and its galacturonic acid are 4.457% and 42.58%, respectively.