In processing of fruits and vegetables to food products, large amounts of wastages are producing from peels and seeds. These wastages contain valuable bioactive compounds such as antioxidants, polyphenols, dietary fibers, pigments and pectins that are currently use as animal feed. In this study, microwave-assisted extraction was applied for pectin extraction from watermelon rind. First, watermelon rind was chopped , blanched , dried and milled. Pectin extraction was conducted under microwave irradiation at three power levels; 100 W (26 min), 300 W (14 min) and 500 W (5 min) and conventional heating extraction (CHE) by heater (150 min) at 90 ° C, pH = 1.5, solid-liquid ratio 1 : 20 . Pectin extraction yield , physico-chemical and functional properties of pectin was examined. The results showed that the extraction yield increased with increasing microwave power (14.39%, 15.26% , 16.01% and 13.15% at 100, 300 , 500 W and CHE respectively). Degree of esterification of the pectin extracted at three power levels 100, 300, 500 W and CHE were 46.25%, 32.35%, 36.89% and 31.67%, respectively, indicating that despite of increasing the degree of esterification, increasing power led to producing low methoxyl pectin . The galacturonic acid contents of the pectin extracted at three power levels 100, 300, 500 W and CHE were 81.5%, 76%, 88% and 27% respectively, showed that the highest amount of galacturonic acid contents obtained at 500 and 100 W, respectively and both of them significantly different from other pectins . WHC was obtained 8.82%, 8.05%, 8.59% and 4.41% at three power levels 100, 300, 500 W %, respectively.Also OHC was obtained 2.42%, 5.15%, 4.68% and 5.66% at three power levels 100, 300, 500 W %, respectively. WHC and OHC of extracted pecti under microwave were significantly different from WHC and OHC of extracted pectin by heater. Appearent viscosity at three power levels 100, 300, 500 W and CHE showed shear thinning behavior. Gel forming capability at three power levels 100, 300, 500 W and CHE was determined 0.139, 0.044, 0.102 and 0.0403 Newton, respectively. Result showed that the pectins extracted at 100 W and 500 W,were not significantly different from each other but were significantly different from other extracted pectins. Protein contents at three powers levels 100, 300, 500 W and the CHE were 7.11%, 8.79%, 7.035% and 8.13%, respectively. The results showed protein contents of extracted pectins were not significantly different from each other. Keywords Watermelon rind, Pectin, Microwave, Power, Extraction
