Quality assessment of Borassus aethiopum Mart fruit pulp pectin precipitated with various solvents

Abstract

Borassus aethiopum Mart fruits are underutilized in Africa and most of them are left to rot in the field. These fruits have great potential as an alternative and commercially viable pectin source for the pectin industry. Physicochemical and rheological characteristics of B. aethiopum pectins are significantly affected by the extraction process which permits the isolation of tailored pectin of specific applications in the food industry. One important step in pectin recovery is its precipitation from the liquid extract and this can considerably impact the quality attributes of the final product. In this study the effects of precipitating solvents (isopropanol, acetone and 50/50 isopropanol-acetone) on the physicochemical and functionalities of pectin recently extracted from B. aethiopum fruit were investigated. Most of the results for the physicochemical characteristics were not statistically different however great variability was noticed in the functional and rheological properties of pectins precipitated with isopropanol (IPA), acetone (ACTN) and the 50/50 IPA-ACTN solvents. Isopropanol precipitated pectin exhibited statistically higher (p<0.05) emulsifying activity and a better gel sensorial property than the ACTN and IPA-ACTN precipitated pectins. Moreover, regardless of the precipitating solvent, high purity pectin with high viscosifying, emulsifying and gelling properties were obtained. Therefore, production of pectin from B. aethiopum fruit pulp must be governed by its intended use since extraction and precipitation processes isolate pectin samples with various functionalities.   Key words: Borassus aethiopum Mart, isopropanol, acetone, precipitating solvent, solvent mixture.