STUDY ON THE INFLUENCE OF HEAT TREATMENTS ON THE ANTIOXIDANT PROPERTIES OF GINGER

Abstract

The purpose of this paper is to study the influence of thermal treatments such as refrigeration, freezing, boiling, and drying on the antioxidant properties of ginger. The determination of antioxidant activity was performed by the spectrophotometric method with the DPPH reagent (2,2diphenyl-1-picrylhydrazyl) and the photometric dosing of the polyphenols by the FOLIN-CIOCALTEU  method. The vitamin C concentrations were also determined by HPLC as well as the spectrophotometric β-carotene content. The analyses performed showed that thermal processes have a significant influence on the antioxidant capacity of ginger. In the drying process there occurs an increase in antioxidant capacity, and in the case of frozen ginger the polyphenol content is higher than in the fresh form or aqueous extract.  Also, the content of β-carotene and vitamin C was higher in the case of dried ginger than in the refrigerated one.