Optimal conditions for extracting high-quality pectin from water hyacinth (Eichhornia crassipes) for less soluble hydrogel production

Abstract

The research aimed to extract high-quality pectin from water hyacinth for less soluble hydrogel production. The product adds value to water hyacinth waste and helps solve environmental problems. The high degree of esterification pectin can be prepared as a hydrogel, which can be used in various pollution treatment applications. The quality of pectin depended on raw materials and extraction conditions. The optimum condition was initially predicted using the response surface method (RSM). Three extraction variables were studied, including pH 1.0-4.0, temperature 50-110ºC, and extraction time 30-240 min. A total of seventeen runs including five replicate runs were studied. Functional groups of pectin were studied using Fourier Transform Infrared spectrophotometry. The degree of esterification and emulsifying properties were determined for assessing the quality of extracted pectin. The result revealed that the extraction conditions strongly affected both the yield and the quality. The condition of pH 2.5, 110ºC, and 30 minutes had the highest degree of esterification of 94.13 % but low yield (1.42%). On the other hand, under the conditions of pH 1.0, 110ºC, and 135 min extract time had the highest yield of 3.85% (about 76.6% of pectin content) however the degree of esterification is low at 43.25 %. Two mathematical models were proposed for yield and number of ester groups. The result will be used for the selection of high-quality pectin to produce insoluble hydrogel for pollution treatment in the future.