Influência do etanol na secagem de maçã Fuji

Abstract

This work had as objective to evaluate the ethanol effect on the drying of Fuji apple and in relation to some physical characteristics. The assays were performed based on experimental design with the temperature (45.9 ºC to 74.1ºC) and relative humidity (14.3% to 32.7%) of the drying air as independent variables, the drying air velocity were constant in 2.5 m.s-1. The dependent variables analyzed were color parameters (L*, b* e a*), the total variation in color (E), browning index (BI), soluble solid content, visual quality, superficial shrinkage and thickness, rehydration capacity, water activity and texture parameters (hardness, work and adhesiveness). The samples were also analyzed through scanning electron microscopy and biospeckle laser technique to determine the correlation among the physical and structural properties. The pretreated samples with ethanol showed higher drying rate but higher browning and apparently more wrinkled state compared to the samples without pretreatment with ethanol. It was observed that the independent variables directly influenced adhesiveness of the samples without pretreatment while adhesiveness of the samples pretreated with ethanol was indirectly influenced. The work and hardness in the samples without pretreatment with ethanol were indirectly influenced by the relative humidity, and pretreatment with ethanol has not altered the effect of independent variables on hardness, work and water activity in the drying. In the samples pretreated with ethanol, rehydration capacity was until 49.38% and lower surface shrinkage was at 60ºC and 23.5% relative humidity of the drying air. And there was also higher visual quality than other samples.