Abstract
The antioxidant abilities of various health teas (i. e., lotus leaf, striped bamboo, persimmon leaf, mugwort, perilla, cedar leaf or dokudami) both singly and in cookies containing these individual teas were examined using a powder model system in the water activity (Aw) range of 0.2-1.0 at 50°C.
Potato starch (control) had no antioxidant ability over the entire investigated Aw range. The peaks of the peroxide value (PV) appeared for the lotus leaf and striped bamboo in the Aw range of 0.2-0.8 and for the persimmon leaf at Aw0.2-0.4. Those PV peaks did not appear for the mugwort, perilla, cedar leaf and dokudami in the entire Aw range.
Cookies were prepared by baking the dough at 160°C for 20 minutes, which consisted of ingredients supporting oil (72% soft flour, 3% baking powder, 25% powdered health tea or potato starch), linoleic acid and water in the ratio 4 : 1 : 1.5 by weight. No antioxidant ability was obtained over the entire Aw range when potato starch (control) was added to the cookies. Although PV peaks for the cookies at a level similar to the control appeared with added persimmon leaf at lower than Aw0.4, no remarkable peaks were observed for the mugwort, perilla, cedar leaf and dokudami at higher than Aw0.6.
