The influence of far-infrared drying parameters on the sensory properties of Georgian black tea

The study investigates the physicochemical and organoleptic properties of black tea dried at different temperatures using advanced technologies to obtain high-quality aromatic tea. Tea quality and health benefits are asso­ciated with essential oils, alkaloids, and phenolic compounds. Tea leaves harvested in May and September were divided into two groups: one dried by conventional hot-air drying and the other by infrared emitters operating mainly in the far-infrared range (8–20 μm). Drying was conducted at temperatures from 75 °C to 95 °C (with 5 °C intervals) until a residual moisture content of 5–7 % was achieved. Under optimal regimes, key physicochemical indicators determining tea quality (taste, aroma, colour, and storage stability) and sensory properties were evaluated. The results showed that for both Martvili and Tkibuli teas, infrared drying at 85–90 °C for ~15 min yielded higher sensory aroma scores and overall sensory quality compared with hot air drying. Tea produced using infrared drying demonstrated superior physicochemical and sensory characteristics compared to conventionally dried tea. Among the samples, infrared-dried Tkibuli tea (extractive substances 370.0 mg·kg-1, total phenolic compounds 170.5 mg·kg-1, sensory score 5.15) outperformed Martvili tea (extractive substances 356.8 mg·kg-1, total phenolic compounds 167.4 mg·kg-1, sensory score 4.95).