Phenolic Content and Antioxidant Capacity of American Persimmon Teas

Regular consumption of green tea (GT), a rich source of phenolic compounds, has been linked to various health benefits, including lowering cholesterol, weight loss and cancer prevention. Green tea is made from Camellia sinensis (L.) Kunzte, and domestic production is currently confined in South Carolina and Hawaii. Since most green tea available on market in the U.S. is imported, there have been concerns for contamination with heavy metals and pesticides. In Asia, leaves and other plant parts of various species are also used to make teas. One example is Asian persimmon (Diospyros kaki Thunb). Its leaves can be simply air-dried in shade, sometimes followed by steaming or immediately steamed and roasted. Asian persimmon tea has anti-allergy, anticancer, anti-inflammatory, and antioxidant properties, and contains phenolic constituents such as astragalin and isoquercitin. Leaves of American persimmon (D. virginianaL.), native to the eastern part of the U.S., have been similarly used to make beverages in the past, although its health benefits have not been studied. The objectives of the study were to examine phenolic content and antioxidant capacity of American persimmon tea processed by two methods. Leaves from five cultivars of American persimmon were harvested in May of 2012. Leaves were washed and lightly dried with paper towel. The samples were weighed, a half of samples were placed in microwavable plastic bag for 30 sec./50g samples.  Immediately after steaming, samples were roasted on an electric skillet at 200 °C. The rest of samples were dried in an oven at 50 ºC for two nights. Folin-Ciocalteu assay was performed to determine phenolic content of teas. Phenolic content of GT was 14.6, and that of PT ranged from 3.9 to 8.2 for roasted samples and 3.2 to 4.0 for oven-dried samples in g of gallic acid equivalent per 100 g of dry weight. Ferric Reducing Antioxidant Power assay was performed to determine antioxidant capacity. This assay revealed that the antioxidant capacity of roasted teas were substantially higher (596.7~1152.7) than that of oven-dried teas (287.0~403.5) in μmol of Trolox equivalent, and comparable to that of GT (1142.5). Teas made from American persimmon leaves are a caffeine-free healthy alternative to regular or green tea.