Ice Sonication–Assisted Enzymatic Extraction of Kangra Orthodox Tea: Impact on Bioactive Profile, Tea Cream Formation, and Organoleptic Quality

Kangra Orthodox tea, prized for its unique flavour and health benefits, requires optimized extraction methods to maximize its potential. This study investigated a novel cold water extraction method employing ice sonication–assisted enzymatic treatment to enhance bioactive yield, mitigate tea cream formation, and improve the organoleptic quality of Kangra Orthodox tea. Different sonication times (10–60 min) and ice concentrations (0–60%) were investigated, while enzyme concentration was kept constant (0.0095%). Results demonstrated that ice sonication significantly enhanced the extraction yield of key bioactive compounds compared to conventional methods (without ice sonication). The optimized ice sonication method yielded the following: 52.68% water extract, 244.45 µg GAE/100 mL total phenolics, 80.40 mM TE/100 mL antioxidant capacity, 36.64 µg CAE/100 mL caffeine, 173.44 µg TAE/100 mL tannins, 0.922% theaflavins, and 8.80% thearubigins. This represents a substantial improvement over the conventional method (without ice), which yielded the following: 46.52% water extract, 214.75 µg GAE/100 mL total phenolics, 70.63 mM TE/100 mL antioxidant capacity, 29.27 µg CAE/100 mL caffeine, 130.54 µg TAE/100 mL tannins, 0.739% theaflavins, and 7.92% thearubigins. This was corroborated by Pearson correlation analysis, which revealed strong positive correlations between the optimized ice sonication extraction method and the increased yield of desirable compounds, alongside a negative correlation with the formation of undesirable tea cream. Furthermore, FTIR analysis confirmed the presence of these targeted bioactive compounds in the optimized tea extracts, further validating the efficacy of this novel extraction method. Optimized ice sonication parameters (40% ice and 30-min sonication time) effectively reduced tea cream formation, resulting in a clearer tea infusion. Sensory analysis revealed that ice sonication positively influenced the organoleptic characteristics of the tea, enhancing its overall quality and consumer acceptability. This novel extraction method presents a promising approach to produce high-quality Kangra Orthodox tea with enhanced bioactive content and improved clarity, catering to the increasing demand for healthier and more appealing tea products.

Graphical Abstract