Impact of high-intensity ultrasound on phenolic content and quality of black tea wine

Tea is the most popular non-alcoholic beverage in Turkiye and worldwide. Black tea, a product of tea leaves fermentation, is the most consumed form of tea in Turkiye. Although a significant amount of tea is produced and consumed globally, there are limited alternative products developed in this field apart from traditional black tea. The objective of this study was to produce tea wine with a high phenolic content from the highly popular and widely consumed black tea in Türkiye. The study aimed to evaluate the influence of ultrasound treatment on the physicochemical properties and overall quality of tea wine, with a particular focus on its impact on phenolic content. The results indicated that ultrasound treatment significantly affected physicochemical properties of tea wine such as total acidity, volatile acidity, total soluble solids, reducing sugar (p<0.05). Ultrasound treatment after brewing increased the total phenolic content (TPC) of tea infusions by 49%. The TPC levels of the samples decreased after fermentation but no significant change occurred in TPC levels duration of two months aging. The color parameters of tea wine were also affected from ultrasound treatment, fermentation process and aging. The L* value of tea wines significantly decreased to 66.41 in samples treated with 50% ultrasound for 8 minutes. Ultrasound treatment was found to influence sensory attributes, with increased amplitude and duration having a negative impact on taste. While there is limited research in the literature on tea-flavored, wine-based beverages, also known as tea wine, our project seeks to produce tea wine using a standardized process. We employed ultrasound, a new food preservation technique, to create an alcoholic drink with high phenolic content from brewed black tea, suitable for year-round production. It is expected that the findings highlighted the potential of tea in the production of diverse products, contributing to the expansion of tea consumption into new areas.