ANTIOXIDANT CAPACITY AND BIOACCESSIBILITY OF PHENOLIC COMPOUNDS IN GREEN AND WHITE TEA INFUSIONS (CAMELLIA SINENSIS).

Teas derived from Camellia sinensis, especially green tea (GT) and white tea (WT), have high levels of bioactive compounds, such as polyphenols, with potential applications in health promotion. However, their presence does not guarantee biological availability, which depends on the bioaccessible fraction released during gastrointestinal digestion. Thus, the present study aimed to evaluate the bioaccessibility of phenolic compounds in GT and WT infusions by characterizing total phenolic compounds, antioxidant capacity, and phenolic profile before and after in vitro gastrointestinal digestion (IVGD). Aqueous GT and WT infusions were subjected to IVGD following the INFOGEST 2.0 protocol. Before and after digestion, total phenolic content (TPC; FolinCiocalteu), antioxidant capacity (FRAP, ABTS, DPPH), and phenolic compounds by HPLC were determined. The bioaccessibility of gallic acid, catechin, caffeine, epigallocatechin (EGC), and epigallocatechin gallate (EGCG) was calculated. Before IVGD, GT showed higher TPC (850.02±25.50 mg GAE/mL) and ABTS antioxidant capacity (30.60±0.67 µM Trolox/mL) than WT (628.95±29.4 mg GAE/mL and 14.87±0.20 µM Trolox/mL, respectively); FRAP and DPPH did not differ between GT and WT. GT showed higher levels of gallic acid (7.60±0.07 mg/100mL) and catechin (4.59±0.28 mg/100mL) than WT (4.65±0.01 and 3.65±0.01 mg/100mL, respectively), whereas WT showed higher levels of caffeine (37.38±1.10 mg/100mL) and EGCG (18.40±1.12 mg/100mL) than GT (20.73±0.06 and 7.38±0.57 mg/100mL, respectively). After IVGD, TPC did not differ between GT and WT (1827.52±17.95 and 1785.63±14.42 mg GAE/mL, respectively), but there was a significant increase in TPC and antioxidant capacity (ABTS and FRAP) in both infusions. GT maintained higher levels of gallic acid (20.62±0.14 mg/100mL) and EGC (12.69±1.05 mg/100mL) than WT (15.24±0.03 and 8.78±0.20 mg/100mL, respectively), whereas WT showed a higher caffeine content (55.47±0.98 mg/100mL) than GT (31.88±0.74 mg/100mL). Catechin was no longer detected and EGCG decreased in both infusions (GT: 1.98±0.45; WT: 4.21±1.12 mg/100mL). Antioxidant capacity by ABTS and DPPH did not differ (141.53±2.57 and 141.98±1.56 µM Trolox/mL; 39.70±0.55 and 39.10±1.82 % AA, respectively), but FRAP differed (GT: 196.67±5.94; WT: 182.58±5.42 µM ferrous sulfate/mL). Regarding bioaccessibility, GT showed higher EGC bioaccessibility (GT: 725%; WT: 230%) and WT, higher gallic acid bioaccessibility (WT: 327%; GT: 272%). Caffeine (GT: 154%; WT: 148%) and EGCG (GT: 27%; WT: 23%) showed similar values. IVGD altered the phenolic profile and antioxidant capacity of GT and WT infusions, increasing the bioaccessibility of compounds such as EGC and gallic acid and highlighting the potential of both as sources of bioactive compounds with antioxidant activity. Acknowledgments: This work was supported by CAPES (Finance Code 001) and FAPERJ (Grant No. E-26/210.058/2025).