Quality properties and taste improvement of fig leaf tea harvested in a tsunami salt-damaged area

Abstract

The Great East Japan Earthquake seriously affected the town of Onagawa in Miyagi Prefecture, in the northern part of Japan. Local fishermen were forced to abandon their businesses because their fishing boats and equipment were completely destroyed or missing following the huge tsunami. Subsequently, they initiated planting of saltresistant plants such as fig tree, hot pepper, and garlic to ensure their financial security. The fig trees were cultivated for the fruits; however, the harvest season of fig fruits was limited. Therefore, the production of fig leaf tea was attempted to expand their income base. The objectives of this study were to investigate the quality properties (components, functional properties, and taste) of fig leaf tea harvested in a tsunami salt-damaged area. The fig leaf tea contained abundant rutin and minerals, especially potassium and magnesium. In contrast, 1-deoxynojirimycin, caffeine, and catechins were not detected. Angiotensin I converting enzyme activity of fig leaf showed similar values to those of houttuynia tea, mulberry leaf tea, persimmon leaf tea, and rooibos tea. The taste properties measured by a taste sensor revealed weak astringent tastes. Additionally, fig leaf tea is a caffeine-free beverage, making it suitable for not only adults, but also those sensitive to the effects of caffeine such as children and pregnant women.