Abstract：
Tea is widely consumed in both beverages and food. Epigallocatechin gallate (EGCG) is the most crucial active ingredient in tea. Currently, knowledges on transformation processes of EGCG during tea processing are lacking. Understanding the chemical reactions of EGCG and its products during tea processing is important for assessing the safety of tea-containing food. Here, we revealed the formation of persistent free radicals (PFRs) from EGCG under the influence of heating and light irradiation, which was substantiated with evidence. These PFRs exhibited stability for >30 min in simulated gastric fluid. Furthermore, we observed potential effects of these PFRs on DNA damage and cell cytotoxicity in vitro. By combining electron paramagnetic resonance spectrometer with Fourier transform ion cyclotron resonance mass spectrometry, we elucidated the pathways involved in free radical formation. These findings are expected to contribute to a comprehensive understanding of free radical chemistry in tea-containing food.
摘要：
茶在饮料和食品中广泛消费。表没食子儿茶素没食子酸酯（EGCG）是茶叶中最重要的活性成分。目前,缺乏对茶叶加工过程中EGCG转化过程的认识。了解EGCG及其产品在茶叶加工过程中的化学反应对于评估含茶食品的安全性非常重要。这里,我们揭示了在加热和光照的影响下，EGCG会形成持久性自由基（PFR），有证据证明.这些PFR在模拟胃液中表现出>30分钟的稳定性。此外，我们观察到这些PFRs在体外对DNA损伤和细胞毒性的潜在影响。将电子顺磁共振谱仪与傅里叶变换离子回旋共振质谱联用,我们阐明了自由基形成的途径。这些发现有望有助于全面了解含茶食品中的自由基化学。
