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Concentration by reverse osmosis of Camu-Camu juice

Barreto, A. G., Carvalho, R. A., Cabral, L. M. C., Matta, V. M., Freitas, S. P.
Acta horticulturae 2014 no.1040 pp. 39-42
Myrciaria dubia, antioxidant activity, antioxidants, ascorbic acid, centrifugation, fruit juices, heat, heat treatment, industry, microfiltration, pretreatment, reverse osmosis, shelf life, Amazonia
Camu-camu is a native fruit from the Amazon region, rich in vitamin C and other antioxidant compounds. Camu-camu juice concentration is an option to increase its shelf-life, reduce transport and storage costs, and add value to the fruit. However, during the concentration by conventional heat treatment, the juice may lose important bioactive compounds, reducing their antioxidant activity. Membrane separation processes have attracted much attention in the fruit juices industry as they are conducted under mild conditions, preserving heat sensitive substances. This study aimed at evaluating the effect of reverse osmosis (RO) concentration on antioxidant activity of the camu-camu juice, taking in account the previous pre-treatment applied, centrifugation or centrifugation followed by microfiltration. Integral camu-camu juice was centrifuged using a basket centrifuge with a 150 µm mesh or centrifuged and microfiltered with a 0.1 µm tubular ceramic membrane. The juice concentration was carried out in a plate and frame module with composite membranes at different operational conditions. The lower loss of vitamin C and total antioxidant activity was reached at 60 bar and 20°C. The preservation of the antioxidant activity and an important decrease in the vitamin C content of concentrated juices independently of the adopted pre-treatment were observed. This fact could be attributed to the vitamin C action, protecting the other bioactive substances. Additionally, when the RO process was carried out with camu-camu juice just centrifuged, the vitamin C loss was higher than when the juice was centrifuged and microfiltered. This occurs probably due to the higher residence time of the centrifuged juice in the RO system caused by its higher suspended solids content. It can be concluded that the membrane residence time is a parameter to be optimized in RO process in order to better preserve the antioxidant compounds of the products.