PREPARATION METHOD SHAPES THE PHENOLIC CONTENT OF COMMERCIAL TEA INFUSIONS

Tea composition is influenced by plant material characteristics and preparation conditions, including temperature, extraction time, and particle properties. Commercial tea bags and capsules may differ in composition and physical characteristics, making it important to distinguish product-related effects from those associated with the extraction system. To evaluate the influence of preparation system and commercial product origin on the total phenolic content of seven commercial tea formulations. Seven formulations were evaluated: lemongrass with ginger, fennel, chamomile, apple-hibiscus-cinnamon, peach mate, red fruits, and green tea with mint. Four preparation conditions were compared: conventional infusion of commercial tea bags (TS), machine extraction of commercial capsules (TC), conventional infusion of capsule contents (CS), and machine extraction of tea-bag contents transferred to reusable capsules (SC). Conventional infusion was performed using 200 mL of water at approximately 90 °C for 5 min. Machine extraction used approximately 200 mL of water at 68 °C, with an extraction time of approximately 18 s. Total phenolic content was determined using the Folin–Ciocalteu method and expressed as milligrams of gallic acid equivalents per liter (mg GAE L⁻¹). Measurements were performed in triplicate, and results were evaluated descriptively. SC presented the highest mean total phenolic content among the four conditions for all seven formulations. Values ranged from 139.0 mg GAE L⁻¹ for apple-hibiscus-cinnamon to 1001.2 mg GAE L⁻¹ for green tea with mint. For the latter, TS and SC yielded 915.0 and 1001.2 mg GAE L⁻¹, respectively, whereas TC and CS yielded 158.6 and 115.4 mg GAE L⁻¹. Peach mate showed a similar pattern, with 475.2 mg GAE L⁻¹ in TS and 480.8 mg GAE L⁻¹ in SC, compared with 194.2 and 226.4 mg GAE L⁻¹ in TC and CS, respectively. These findings suggest that the origin and characteristics of the commercial plant material contributed to the observed variation. However, differences in composition and sample mass were not controlled, preventing the exclusive attribution of these results to the extraction system. Machine extraction of tea-bag contents in reusable capsules was associated with the highest mean total phenolic content across all formulations. The results highlight the importance of considering both product origin and preparation conditions when assessing the chemical composition of tea infusions.