Antioxidant activity and total phenolic content of three varieties of Ginger (Zingiber officinale) in decoction and infusion extraction method

Abstract

Ginger is one of the plants that is rich with phenolic compounds. This research was aimed at determination of the total phenolic content and antioxidant activity in the rhizome of ginger. However, there is only few information available about the comparison of phenolic compounds and antioxidant activity in the three varieties of ginger. This research employs a descriptive quantitative research using extracted dried gingers on two types of extraction processes, i.e. infusion and decoction. The phenolic compound analysis is conducted by using the Folin-C method, while antioxidant activity was conducted by using DPPH and measured by using Spectrophotometer. Based on ANOVA test result, the highest phenolic was red ginger 12.2533 mg GAE/g (infusion) and 22.9767 mg GAE/g (decoction) followed by emprit and elephant ginger. The highest antioxidant activity by infusion process was found in red ginger of 79.83 % followed by 70.43 % and 61.70% in emprit ginger and elephant ginger. Conversely, the highest antioxidant activity by decoction was found 78.76 % in emprit ginger, followed by 70.56 % and 60.93% for red ginger and elephant ginger. Ginger have sufficient antioxidant activity on extraction by infusion or decoction and the red ginger have a higher phenolic content.