Effect of infusion conditions on bioactive compound content and antioxidant activity in tiger milk mushroom tea

Tiger milk mushroom (Lignosus rhinocerus) is a medicinal mushroom with a sclerotium buried in the soil. The mushroom sclerotium is formed by the fusion of mycelium and contains important substances such as polysaccharides and bioactive compounds in the family of phenolic compounds, flavonoids, triterpenoids, etc. The medicinal properties of sclerotium have been used to treat diseases since the past, especially respiratory diseases, resulting in the consumer's demand for tiger milk mushrooms. Consumers often infuse tiger milk mushroom sclerotium powder in boiled water (100 ˚C), stir well, let the sediment settle at the bottom of the cup, and then drink the clear part. Therefore, using tiger milk mushroom sclerotium to develop a medicinal mushroom tea is another option for health care. The purpose of this research was to determine the optimum conditions for infusing tiger milk mushroom tea. The infused tea was then analyzed for total phenolic, total flavonoid, total polysaccharide, total triterpenoid, total protein content, and antioxidant activity (DPPH and FRAP assay). The results showed that the duration of tea infusion had a statistically significant effect on the bioactive compounds and antioxidant activity (p<0.05). Tea infusion in boiling water for 30 minutes yielded the highest total phenolic content (21.91±0.35 mg GAE/g extract), total polysaccharide content (1,284.10±10.11 mg glucose/g extract), and DPPH inhibition (26.44±0.56%). Increasing the infusion time to 60 minutes resulted in the highest total flavonoid content (14.27±0.15 mg CE/g extract), total triterpenoid content (20.34±0.24 mg ursolic acid/g extract), and Ferric Reducing Antioxidant Power activity (15.23±0.81 µM Fe(II)/g extract). On the contrary, the total protein content decreases with a longer infusion time. From the above research results, it can be concluded that the optimal time to infuse tiger milk mushroom tea is around 30-60 minutes, depending on the type of bioactive compounds required.