Extraction and characterization of pectin from Kaffir Lime (Citrus hystrix)

The present study was focused on the potential of kaffir lime (Citrus hystrix) peel to be a source of pectin. Kaffir lime belongs to the citrus family and has a thicker skin which can be used as a source of pectin. Pectin was extracted from kaffir lime peel using three different acids (citric, hydrochloric or nitric) and at different temperature (45-90°C). Also, sun-dried and microwave-dried peels were studied at the same extraction time (1 hour) and pH (1.5). Pectin yields varied from 10.4% to 59.30% for sun dried peel while for microwave dried peel was 25.9% to 61.80%. The best extraction condition is using citric acid at 90°C using microwave-dried peels. The isolated pectin contained 12.40% moisture, 85.07% anhydrouronic acid (AUA), equivalent weight at 234.742, 1.78% methoxyl content and 11.86% degree of esterification. Purification using alcohol precipitation procedure (APP) was sufficient to yield pectin of high purity. This is supported by content of AUA which is higher than 65% for most of the pectin isolates. According to the values of methoxyl content and degree of esterification, pectin isolated from Kaffir lime peels can be classified as low metholoxyl pectin and are of potential use in manufacture of low sugar products such as low sugar jam and jellies.