Abstract
An infusion of the wolfberry (Lycium barbarum L.) is a traditional Asian herbal tea. This is the most commonly consumed form of dried wolfberry worldwide, yet little scientific information on wolfberry infusions is available. We investigated the effects of making infusions with hot water on the color, the content of bioactive compounds (polysaccharides, polyphenols, flavonoids and carotenoids) and the antioxidant ability of wolfberry infusions. The contents of bioactive compounds and the antioxidant activity of a wolfberry infusion increased with increased infusion temperature and time. Total polysaccharides content (TPOC), total polyphenols (TPC), total flavonoids (TFC) and total carotenoids contents (TCC) were important for determining the antioxidant capacity of wolfberry infusions with the contribution to antioxidant activity in the order TPC > TFC > TCC > TPOC. Hierarchical cluster analysis indicated preparation conditions of 100 °C for 1~3 h, 90 °C for 2~3 h and 80 °C for 2.5~3 h were equivalent as regards the value of TPC, TPOC, TFC, TCC, FRAP, DPPH and ABTS. The results of this study suggest the length of time of making a wolfberry infusion in actual real life practice is too short and different dietary habits associated with the intake of wolfberry infusion might provide the same bioactive nutrients.