Yield and composition characteristic of Citrus nobilis pectin extracted under acidic condition

Abstract

Pectin is a polymeric compound that can bind to water and form a gel. The ability to form a gel depends on the methoxyl group contained in the pectin. The higher of methoxyl content in the pectin caused the faster of gel formation. One of the orange fruits which has a high pectin content is Citrus nobilis. In this study, extraction of pectin from Citrus nobilis was performed using acid solutions in several strong acids (HCl, H2SO4, and HNO3). Yield and composition characteristics of the extracted pectin were studied. The effect of the acid solvents on the methoxyl content was also investigated. The optimum condition for extraction of pectin is using acid concentration of 0.5 M HCl, 0.5 M H2SO4, and 0.5 M HNO3, pH 1.5, temperature of 95°C and extraction time of 60 min. The yield of pectin obtained using the three different acids was 21.8, 18.2, and 14.3%, respectively. Analysis of moisture content was obtained at 10.3, 12.5 and 10.7% for HCl, H2SO4, and HNO3, respectively. Low moisture allows for longer storage and avoids microorganisms. These results showed the extracted pectin using hydrochloric acid (HCl) has a higher yield (21.8%) and methoxyl content (7.10%). Extraction of dried Citrus nobilis peels with 0.5 M HCl solution and extending the extraction time to 60 min resulted in high pectin and high methoxyl content. The high methoxyl content in pectin is high potential to form a gel.