COMPARISON OF ANTIOXIDANT ACTIVITY AND TYROSINASE INHIBITION IN FRESH AND PROCESSED WHITE RADISH, GARLIC AND GINGER

Abstract

In Thailand, there is a diversity of vegetables and fruits due to being a tropical rain forest as well as these are good source of loaded with vitamins, minerals and phytochemicals. Examples of phytochemicals are flavonoid, phenolic, anthocyanin and carotenoid which have been proved to be antioxidant, prevented some diseases and lead to better health. The fresh and processed white radish Raphanus sativus, garlic Allium sativum and ginger Zingiber officinale are consumed on daily basis. They are popular for cooking and preservation e.g. pickle. The objective of this work is to compare antioxidant activity and tyrosinase inhibition between fresh and processed vegetables. This study determined the antioxidant activity such as 1,1-diphenyl-2-picryl-hydrazyl (DPPH), 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS), total flavonoid and phenolic contents as well as tyrosinase inhibition in fresh and processed vegetables. They were collected from three representative markets in Bangkok. The results showed that DPPH in processed white radish was 84.99 ± 11.39% and fresh ginger was 80.90 ± 5.70%. The ABTS test on processed ginger and fresh garlic were 109.39 ± 4.34% and 48.30 ± 8.38% respectively. The highest total flavonoid contents of garlic were 8.85 ± 1.08, 2.26 ± 0.88 mg/100g in fresh and processed respectively. Total phenolic contents of garlic were 1.76 ± 0.33, 19.48 ± 5.51 mg/100g in fresh and processed respectively. The tyrosinase inhibitory activity was highest in fresh ginger 363.71 ± 58.75% and processed garlic 151.42 ± 15.12%. These studied vegetables could be an alternative choices for the advantage consumption diet. They have been shown to be a novel rich source of phytochemicals. These can be antioxidant, tyrosinase inhibition and healthiness.