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.
