Acta Scientiarum Polonorum Technologia Alimentaria

Background. Osmotic dehydration (OD) is a technology that allows the concentration mainly of fruits and vegetables, without change of phase, through partial water removal, when immersed in a hypertonic solution of sugar, salt or others. It can be successfully applied to some products whose production is not fully marketed in fresh form. However,
an additional process is necessary to stabilize the product. The process leads to the achievement of high quality alternative products, with an extended shelf-life, economy
in storage and transport. The aim of this work was to study, at a pilot scale, the behaviour evaluation of a sucrose dehydration solution, during twelve OD reuses, and the quality
of processed mandarins.

Material and methods. The process was carried out using mandarins (Citrus reticulata Blanco) cv Clementina Nova, from Algarve, Portugal, manually peeled and segments chemically skinned. In assays a 60°Brix sucrose solution was used, conducted in thermo-
-stabilized baths, at 45°C, 16 h, 40 oscillations per minute and a fruit:solution ratio of 1:2 (m/m). After each OD cycle, the solution was filtered and reconcentred to 60°Brix
by sucrose addition, and adjusted to original volume. The osmodehydrated mandarins were stabilized by pasteurization. The drying solution behaviour and mandarins’ quality were assessed through different physical, chemical and microbiological analysis.

Results. The factorial discriminate analysis allowed to distinguish a different behaviour between the original and final dehydration sucrose solution during OD processes, but did not affect its desiccant power, only a high pollutant load development explained by BOD₅ values. The results of osmodehydrated mandarins showed that stability was achieved by “combined process” with pasteurization.

Conclusions. The resultslead to concludethat osmotic dehydration process is a good option to improve mandarin’s stabilization, after pasteurization, increasing added value.
Its viability is connected to the management of the drying solution and the number of uses depends on the type of product being dehydrated and their processing sequence. Though the negative microbial load, it must be given attention to dilute the solution before its release as effluent.