Antioxidant activity of the Sumaeyaksuk tea extracts prepared with different drying and extract conditions

In this study, we examined the antioxidant activity of the Sumaeyaksuk (Artemisia argyi) tea extracts from different
pre-treatment and extraction methods. Sumaeyaksuk was sun-dried for 3.5 days (control, RC) and aged at a temperature
of 60℃ for 3.5 days (HA), 7 days (HB), and 14 days (HC), respectively. Each sample was extracted in 60℃
and 95℃ hot water for 2 minutes. The soluble solids content of HA from the 60℃ and 95℃ hot water extraction
were 0.52±0.18% and 0.92±0.18%, respectively. The soluble solids content was increased by the higher extraction
temperature. The reducing sugar content of RC was 9.55±0.18 mg/g in the 95℃ extraction, which was significantly
higher than in the 60℃ extracted sample. However, the reducing sugar content did not show a remarkable difference
based on aging periods. The total phenolic compound content of the 95℃ extracted samples was 3.36±0.13~9.88±0.23
mg/g, which was significantly higher than that of the 60℃ extracted sample. The ABTS radical scavenging activity
of the 60℃ extracted RA and HA samples were 35.63% and 95.10%, respectively. Moreover, the radical scavenging
activity increased to 63.35% and 96.78%, respectively, in the 95℃ extracted samples. As a result of the high
temperature, the extracted sample showed an increase in the FRAP. In the RC sample, the FRAP was two times
higher in the 95℃ extracted sample (181.28±2.90 μM) than in the 60℃ extracted sample (83.88±0.43 μM).

Key words：Sumaeyaksuk, aging, extraction temperature, antioxidant activity