Efeito da desidratação osmótica na qualidade das passas de maçanica - Ziziphus Mauritiana obtidas em Maputo e Tete

Abstract

The apple is a native fruit, rich in vitamin C that can play an important role in the nutrition of food insecure populations and be a source of additional income for small farmers. However, it has high humidity; and is easily spoiled. As a form of preservation, the present work aimed to evaluate the effect of osmotic dehydration as a pre-treatment before drying, on the quality of maçanica raisins obtained in Maputo and Tete. Physico-chemical analyzes of the “in natura” maçanica were carried out. Osmotic dehydration (OD) occurred in osmotic solutions of 40, 45 and 50 oBrix, at 55 oC for 6 hours. Drying was carried out in an oven at 60 °C for 24 hours. Osmotically dehydrated samples were analyzed and compared with fresh samples in terms of: moisture content (%); soluble solids (oBrix); water activity, color and vitamin C. The OD results showed that the mass loss is favored by the increase in the concentration of the osmotic solution, with greater losses being found in samples pre-treated in a 50 oBrix solution, where the Tete maçanica lost 15.3% and that of Maputo 13.3%. Of the parameters analyzed after DO, vitamin C suffered more degradation due to its water-soluble character. The reduction in humidity resulted in values ​​between 71.6 and 77% in the Maputo masonry and between 45.9 and 57.2% in the Tete masonry. There was an average decrease of 3.9% in water activity in both burners and an increase in soluble solids after pre-treatment, in relation to the “in natura” burner. After convective drying, humidity values ​​between 8.9 to 16.8% were reached in all samples. At the end of the pre-treatment and drying, there was a greater tendency to browning in relation to the “in natura” firewood, mainly in the firewood obtained in Tete.(TRADUÇÃO NOSSA)