A process variable study of apple pectin extraction

Abstract

Dried Amasya apple pomace was used for extraction of apple pectin in this process variable study. Process variables of the extraction process were chosen as extraction temperature, duration of the extraction and acidity of the extraction medium. The effect of these variables on the yield and quality of pectin obtained were studied. To determine the quality of pectins their equivalent weights and methylester contents were measured. by titrating 0.5 per cent water solutions of pectins obtained with dilute alkali. Using the titration results total anhydrouronic acid contents of pectins were calculated. Absolute viscosities of one per cent water solutions of pectins obtained were measured. The results showed that pectin yield increased with time and temperature. It was seen that yield increase was directly related to the extraction time and the temperature effect was similar in all levels studied. The anhydrouronic acid content·of pectins increased with temperature. The methylester content of pectins- showed similar behaviour. as anhydrouronic acid content. The constant temperature lines crossed each other near 750 °C - 45 min point. At lower temperatures pectins with higher degree of esterification were obtained. The results showed also that pectin yield increased with increasing acidity. Anhydrouronic acid content was highest acidity and pectin with lower methylester content was obtained. Degree of esterification of pectins extracted increased with decreasing acidity of extraction medium. Experimehtal runs showed deviations from the literature as a result of the clqrification problem.