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Fluoride Content of Matcha Tea Depending on Leaf Harvest Time and Brewing Conditions.
Abstract
Matcha, or powdered green tea (Camellia sinensis) of the Tencha type, is popular all around the world, and its consumption continues to rise. Because of its unique cultivation method, it is rich in phytochemicals and has many health-promoting properties; it contains high concentrations of polyphenols, theanine and chlorophyll. Tea, and by extension matcha, contains numerous minerals, one of which is fluorine. Under physiological conditions, this mineral plays a significant role in hard tissue mineralisation processes. However, even in low concentrations, with prolonged exposure, fluoride can accumulate in the body, leading to a number of harmful effects. The aim of this study was to evaluate, for the first time, the fluoride content of the matcha infusions from different harvests, brewed using water at different temperatures (25 °C, 70 °C, 80 °C and 90 °C). The content of fluoride ions was measured by the potentiometric method. The fluoride content ranged from 3.36 to 4.03 mg/L and was dependent on both the leaf harvest time and brewing temperature. The concentration of this mineral in the dry powder ranged from 118.39 to 121.65 mg/kg. Irrespective of the water temperature or harvest time, matcha was found to have a high fluoride content, with particularly high concentrations being noted in the powder itself.
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4. Conclusions
Our study showed that the harvesting date for matcha tea leaves was shown to have a significant effect on the fluoride content of the dried tea (traditional vs. daily). Matcha daily (from the second and third harvest) had a significantly higher concentration of fluoride. In the case of matcha tea, the temperature of the water used to prepare the infusions also had a significant effect on the fluoride content of the beverage. An analysis of the results showed that the higher the water temperature, the higher the fluoride content in the tea.
However, matcha tea, irrespective of the harvest date or brewing temperature, is a major source of fluoride in the human diet. One litre of this beverage can contain approximately 4 mg of fluoride, providing the total daily requirement for this mineral. The lowest fluoride content was found in the beverage made at 25 °C, entailing the safest dose for humans, which this study brings to light for the first time. Matcha powder, which is increasingly popular as an ingredient in various dishes, contains a very high level of this mineral (120 mg/kg). Despite its valuable health-promoting properties and the abundance of phytochemicals, it is important to control the amount of matcha in one’s daily diet and to take into account other sources of fluoride.