Effect of different drying temperatures on the composition and antioxidant activity of ginger powder

The influence of drying temperatures ranging from 40° to 100°C on the chemical composition, antioxidant properties and microstructure characteristics of the ginger powders was investigated. The ginger samples dried at 100°C showed a significantly higher amount of polyphenols (24.154 mg EAG/g) and flavonoids (10.564 mg EAG/g) contents. Moreover, the antioxidant activity increased from 73.47% at 40°C to 78.23% at 100°C. The reduction trend of 6-gingerol and β-carotene concentrations was obtained by rising the drying temperatures as indicated by high performance liquid chromatography (HPLC) analysis. In contrast, zingerone and 6-shogoal contents significantly increased at high drying temperatures. A pronounced gelatinization and a more compacted structure was observed in the ginger powders dried at high temperatures (80 and 100°C) as indicated by scanning electron microscopy analysis. These findings offer a better comprehension of the influence of the oven drying process on the functional properties and structure characteristics of the ginger powder, hence allowing the optimization and development of applications in the food and pharmaceutical industries.