Yacon tubers contain various bioactive including flavonoids and phenolic compounds, having antioksidant properties. The aim of the study: to obtain the effect of using natural inhibitors on the antioxidant activity of yacon tubers syrup. Phytochemical tests are used in the determination of flavonoids, phenolic content  and antioxidant activity. Total content of phenol and flavonoid were measured by spectrophotometry, while the antioxidant activity was measured by DPPH method. The results showed that the use of natural inhibitors affects the antioxidant activity of yacon tuber syrup. The content of flavonoids and phenolic compounds in yacon syrup using natural inhibitors were 74.046 and 38.894 ppm, significantly different from yacon syrup without inhibitors 50.461 and 30.590 ppm. Antioxidant activity of syrup with natural inhibitors were 52.888% and IC50: 6.383, ​​while yacon syrup without inhibitors were 24.388% and IC50: 11.180.

Keywords: yacon syrup, phenolic, flavonoid, antioxidant