Efeito da pasteurização, da acidificação e da temperatura de conservação na estabilidade do sumo de canhú (sclerocarya birrea)

Abstract

Marula (Sclerocarya birrea) is one of the most valued fruit trees, due to its high socio-economic and cultural importance in rural communities in Africa, including Mozambique. Its fruits are consum fresh and mainly used in the production of jellies, juices and alcoholic beverages. Fresh marula juice is rich in vitamin C and minerals; however, due to its seasonality and high perishability, it has a relatively short period of consumption and conservation. The juice extract residue (foam) is an important fraction, mainly due to its high fiber concentration. In order to assess the effect of pasteurization, pH and storage Temperature on the physicochemical stability of marula juice, the present work was carry out with samples of marula juice produced with the pulp of fruits collected in the districts of Manhiça and Catembe. A portion of the marula juice samples were adjusted to pH 3, using a 10% citric acid solutionpasteurized at 65°C for 30 minutes and stored at room temperature and under refrigeration at 7°C. The stability evaluation were based on the determination of pH and total soluble solids (TSS) analyzed during 32 days of storage, specifically on 1, 2, 4, 8, 16, 24 and 32 days after juice prodution. In addition, the residue of the pulp extract obtained in the production of marula juice was characterize based on the physicochemical parameters. The results showed that the combination of citric acid addition, pasteurization and refrigeration were efficient in the stability of pH and TSS content in both juices, being considered the best treatment for 32 days of marula juice storage. The mean values of pH ranged from 3.04 to 3.25 and the TSS content ranged from 13.1˚Brix to 14.05˚Brix in Manhiça juice, while for Catembe juice the pH ranged from 3.03 to 3.54 and TSS content from 11.9˚Brix to 12.2˚Brix. The study shows that marula juice can have its shelf life extended with the modification of physical-chemical conditions. The chemical analysis of the residue from juice extraction of marula from Manhiça and Catembe presented the following results in terms of fibers (17.06, 33.47 g.100g-1 ), lipids (6.96, 9.47 g.100g-1 ) and proteins (3.10, 6.41 g.100g-1 ) respectively, showing potential nutritional value.