Physicochemical Properties and Antioxidant Activities of Sasa borealis-Based Tea Extract Blends

The physicochemical properties and functional activities of Sasa borealis-based tea extract blends were evaluated, focusing on those of blends with S. borealis with Tagetes erecta L. and Prunus mume. The properties of four groups of extracts were compared: Sasa borealisalone (SS), Sasa borealis-Tagetes erecta L. (ST), Sasa borealis-Prunus mume(SP), and Sasa borealis-Tagetes erecta L.-Prunus mume(STP). The moisture content was the highest and lowest in the ST (3.41%) and SP (2.74%) groups, respectively. Colorimetric analysis showed that the SP group was the darkest (L value of 50.38) owing to the high pigment concentration in P. mume, and the a value of the STP group was the highest (-2.04). The b values of all blends were higher than those of the SS group, with that of the STP group (11.49) reflecting the effects of the carotenoid and flavonoid pigment contents. The total polyphenol and flavonoid contents were the highest in the STP group (1,948.19 mg GAE/g and 4,354.95 mg RE/g, respectively); the flavonoid content was 1.4-fold higher in the STP group than in the SS group. The antioxidant activity (DPPH radical scavenging, IC₅₀) was substantially higher in the STP, SP, and ST groups (87.85, 93.20, and 118.01 μg/mL, respectively) than in the SS group (506.86 μg/mL), confirming that blending T. erecta Land P. mume with S. borealis increased the antioxidant activity compared with that of S. borealis alone. The nitrite scavenging activity (IC₅₀) was the highest in the STP group (180.40 μg/mL). The total amino acid content and essential amino acid ratio (29.91%) were also the highest in the STP group (1,445.64 mg/100 g), with proline, serine, valine, GABA, and aspartic acid being the predominant amino acids in this group. The amino acid contents and essential amino acid ratios were higher in the SP and ST groups than in the SS group. In conclusion, the moisture content, color, polyphenol and flavonoid contents, antioxidant and nitrite scavenging activities, and amino acid composition of the S. borealis-based extract blends were superior to those of the single S. borealis extract. These parameters were the highest in the STP blend, suggesting that S. borealis extract can be blended with extracts of various other plants to develop new functional beverages.