2‐tert ‐Butyl‐1,4‐benzoquinone (TBBQ), the main oxidation product of tert ‐butyl‐hydroquinone (TBHQ) during frying, is cytotoxic and its residual levels in frying oils and foods are unknown. In this study, TBBQ residues have been evaluated during the preparation of french fries. Results showed that frying at 140 °C resulted in the highest TBBQ peak concentration (48.42 mg kg⁻¹) compared with frying at 190 or 170 °C. This unexpected finding can be attributed to more extensive hydrolytic reaction when frying at the lower temperature, generating more peroxyl radicals. TBBQ concentrations proved to be independent of the oil type among various unsaturated oils. However, higher TBBQ levels were observed in saturated palm oil and crude soybean oil than in unsaturated oil or refined oil. Continuous frying leads to the accumulation of a large amount of TBBQ in fried food. After frying 1–5 batches, TBBQ levels in both the frying oil and fries were above 10 mg kg⁻¹, exceeding its critical cytotoxic concentration (IC₅₀ value of 10.71 mg kg⁻¹ for RAW 246.7 cells in our previous study), warranting concern with respect to the safety of fried food. FTIR has been utilized as an effective tool for visually monitoring the degree of oxidation in the frying medium with respect to its hydrogen peroxide level, which contributes to the increased level of TBBQ derived from TBHQ therein.

中文翻译：

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反复深油炸过程中，油炸油和油炸食品中的2-叔丁基-1,4-苄基醌积累

2-叔丁基-1,4-苯醌（TBBQ）是叔丁基对苯二酚（TBHQ）在油炸过程中的主要氧化产物，具有细胞毒性，其在油炸油和食品中的残留量尚不清楚。在这项研究中，已经在炸薯条的制备过程中对TBBQ残留物进行了评估。结果表明，在140°C下油炸会导致最高的TBBQ峰值浓度（48.42 mg kg ^-1）与在190或170°C下油炸相比。此意外发现可归因于在较低温度下油炸时发生更广泛的水解反应，从而产生更多的过氧自由基。在各种不饱和油中，TBBQ的浓度与油的类型无关。但是，在饱和棕榈油和大豆粗油中观察到的TBBQ含量比在不饱和油或精炼油中更高。连续油炸会导致油炸食品中大量TBBQ的积累。炸1至5批后，炸油和炸薯条中的TBBQ含量均高于10 mg kg ^-1，超过其临界细胞毒性浓度（IC ₅₀值为10.71 mg kg ^-1对于我们之前的研究中的RAW 246.7细胞），值得关注的是油炸食品的安全性。FTIR已被用作有效的工具，以可视方式监测油炸介质中过氧化氢水平的氧化程度，这有助于增加其中的TBHQ产生的TBBQ水平。