To determine the most appropriate solid to solvent ratio toextract pectin, rind to water ratios of 1:10–1:30 were used in thisstudy and the results were in Fig. 2c, e–f. As shown in figures, thepectin extraction was significantly increased up to the solid-to-liquid ratio of 1:20.3. The pectin content was decreased with thefurther increase in solid-to-liquid ratio. The solvent (water) canefficiently absorb microwave energy and leads to enhance swellingof plant material, which is favorable to increase the contact sur-face area between the plant matrix and the solvent, resulting inincreases the extraction yield of pectin up to solid–liquid ratio of1:20.3. But, higher solvent would decrease the microwave adsorp-tion of material, because more energy was absorbed by the solvent.Therefore, the break of material cell wall and mass transmissionmight be negatively influenced (Li et al., 2010) and decreased thepectin yield.