Hazel leaves as novel herbal tea ingredient: Evaluation of functional properties, sensory characteristics, and consumers’ acceptability

Although hazel leaves have historically been used in traditional medicine, they have not yet been studied as an ingredient in food or beverages. This research investigates the potential use of Corylus avellana L. (hazel) leaves in the preparation of herbal teas. The impact of two drying methods, Air Drying (AD) 50°C/3 h and Microwave Drying (MWD) 400 W/4 min, on the phenolic content, volatile aroma compounds, sensory profile, and consumers’ acceptability of the resulting herbal teas was evaluated. The results showed that MWD determined a higher total phenolic content (0.78 mg/L GAE) compared to AD (0.70 mg/L GAE), while the DPPH assay showed a similar antioxidant capacity (35.4% AD vs 35.6% MWD). Volatile compound and sensory analyses revealed that MWD enhanced the formation of aldehydes and ketones associated with fruity, citrus, and sweet notes, whereas in AD samples, grassy and herbaceous volatiles such as unsaturated alcohols and aldehydes prevailed. Consumers’ acceptability, evaluated through the Hedonic Scale Method, demonstrated a clear preference for MWD herbal teas. Overall, hazel leaf herbal teas represent a promising approach to valorizing agricultural by-products, combining health-promoting potential with sustainability. MWD emerges as the more suitable drying technique to optimize both functional and sensory qualities, highlighting practical applications in the herbal tea industry, in line with current consumer trends and the rapidly growing herbal tea market.