Influência de diferentes métodos de secagem e da temperatura nas características físicas e químicas do gengibre

Abstract

The objective of this work was to explore three different ginger drying methods (heater with and without forced circulation of air at temperatures of 50, 60, 70 and 80ºC, in addition to lyophilization) and to evaluate the influence of the drying process on the physical and chemical characteristics of dry ginger. Dryings were performed for ground and cube ginger. The analyzes carried out in the work were: the content of phenolic compounds, the total titratable acidity, the lipid oxidation through the analysis of TBARS, color and water activity. For characterization analyzes of fresh ginger, 14 milliequivalents of base / 100 g were obtained for titratable acidity, phenolic compounds content of 536 mg of Gallic Acid / 100 g, humidity of 90% and water activity of 0.98. The sequestration capacity of the DPPH radical was 6.5%, the TBARS content was 4.30 mg malonaldehyde / kg. For the color parameters 52.8, 28 and 80 were obtained for the luminosity (L *), saturation (C *) and hue (H *), respectively. As the study of drying kinetics in the different equipments, the equilibrium humidity was reached in less time for the heater with air circulation. For the heater the ground ginger dried faster than in cube. The drying rate was faster with increasing temperature. In the lyophilization the ground and cubed ginger reached equilibrium moisture at the same time, but it was higher than for the heater with air circulation. The sequestration capacity of the DPPH tends to increase with the temperature in the heaters, the same was observed for the lyophilization process. With the temperature increase there was an increase in acidity, a more pronounced effect for the heater without air circulation and lyophilization. It was observed that lyophilization preserved the phenolic compounds more and drying in heater caused a small reduction in this characteristic. The values of TBARS increased with the drying temperature and it were higher for the heater without circulation of air, however, in the lyophilization we have values similar with in natura. As for the color analyzes the dry ginger tends to be quite bright (L*), less intense color and has a greater tendency to yellow color. However, there were no significant changes in the sample characteristics, so it is recommended to dry in an heater with air circulation at 80ºC because it is a faster process.