Extraction, physicochemical analysis and characterization of pectin from sweet orange (Citrus sinensis), lime (Citrus aurantifolia) and lemon (Citrus limon)

Pectin was extracted by a modified McGready (1996) method from Sinensis, Aurantifolia and Limon species of citrus and then precipitated by 95% acetone. Furthermore, the obtained pectin was qualitatively and quantitatively characterized to compare certain physical and chemical properties. Obtained results indicated that the three species have the same colour, brown and are insoluble in both cold water and cold alkali but soluble at elevated temperature. The equivalent weight in mg/mL was found to be 1849.62, 1388.89 and 1720.20 for C sinensis, C aurantifolia and C limon respectively, while the % methoxyl content determined gave the value of 4.19, 5.60 and 4.51% in the same order. The percentage moisture content obtained from the 3 fruits was 60.53, 59.80 and 78.00%, for C sinensis, C aurantifolia and C limon respectively. The percentage yields of the pectin on wet basis are 35.44, 36.48 and 30.09% while on dry basis were 3.74, 3.85 and 4.97%, in the same order with C limon having the highest percentage yield of pectin on dry basis. The pH determinations for the pectins were found to be C sinensis 4.3, C aurantifolia 4.9 and C limon 5.0.