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).