Extraction of pectin from dehydrated guava

Pedro Sato cultivar guavas (Psidium guajava L.) were used for extraction of pectin. The fruits were divided into pulp and pulp with peel, and dried in a stove with air circulation. Dry samples were characterized physically and chemically. The planning consisted of central axial rotation with four points, and three replicates in the central point were used to determine the extraction yield of pectin flour from the guava pulp and pulp with peel. The extraction was performed in 4 g of flour to 200 mL of solution of citric acid at different concentrations and at different times of extraction, at a temperature of 97 degrees C. The pectins obtained in optimum conditions for extraction were characterized. The extraction of pectin with citric acid and alcohol precipitation provided yield above 11% for the guava flour, with pulp and pulp with peel. The best conditions for the extraction were: concentration of citric acid 5 g.100 g(-1) and extraction time of 60 minutes. Pectins obtained demonstrated low esterification and with a level of galacturonic acid close to the commercial standard (65%).