College of Food Science, Woosuk Univ., Samrea-Up, Wanju-Kun, Jeonbuk Province, Republic of Korea.
J Food Sci. 2010 Aug 1;75(6):C506-13. doi: 10.1111/j.1750-3841.2010.01669.x.
Singlet oxygen quenching by synthetic antioxidants (BHA, BHT, and TBHQ) was directly observed by spectroscopic monitoring of luminescence at 1268 nm. The luminescence data showed unambiguous evidence of singlet oxygen quenching by synthetic phenolic antioxidants with the highest activity for TBHQ, followed by BHA and BHT. The protective activities of these synthetic antioxidants on alpha-terpinene oxidation with chemically-induced singlet oxygen under dark further confirmed their singlet oxygen quenching abilities. Total singlet oxygen quenching rate constants (k(r) + k(q)) of BHA, BHT, and TBHQ were determined in a system containing alpha-terpinene (as a singlet oxygen trap) and methylene blue (as a sensitizer) during light irradiation, and the values were 5.14 x 10(7), 3.41 x 10(6), and 1.99 x 10(8) M(-1)s(-1), respectively. After the k(r) value of alpha-terpinene was first determined, the k(r) values of the synthetic antioxidants were calculated by measuring their relative reaction rates with singlet oxygen to that of alpha-terpinene under the identical conditions. The k(r) values of the BHA, BHT, and TBHQ were 3.90 x 10(5), 1.23 x 10(5), and 2.93 x 10(6), M(-1)s(-1). The percent partition of chemical quenching over total singlet oxygen quenching (k(r) x 100)/(k(r) + k(q)) for BHA, BHT, and TBHQ were 0.76%, 3.61%, and 1.47%, respectively. The results showed that the synthetic antioxidants quench singlet oxygen almost exclusively through the mechanism of physical quenching. This represents the first report on the singlet oxygen quenching mechanism of these synthetic antioxidants. Practical Application: The synthetic antioxidants, especially TBHQ, have been found to have a strong singlet oxygen quenching ability. This article also clearly showed that singlet oxygen quenching by synthetic antioxidants was mainly by the physical quenching mechanism. The results suggested that these synthetic antioxidants, especially TBHQ, could be used practically for the protection of the food components such as edible oils and vitamins against singlet oxygen induced oxidations without significant losses of antioxidant activity during storage under light.
通过在 1268nm 处监测发光来直接观察合成抗氧化剂（BHA、BHT 和 TBHQ）对单线态氧的猝灭。发光数据为合成酚类抗氧化剂猝灭单线态氧提供了明确的证据，其中 TBHQ 的活性最高，其次是 BHA 和 BHT。这些合成抗氧化剂在黑暗中用化学诱导的单线态氧对α-松油烯氧化的保护活性进一步证实了它们的单线态氧猝灭能力。在包含α-松油烯（作为单线态氧陷阱）和亚甲蓝（作为敏化剂）的系统中，在光照射下确定了 BHA、BHT 和 TBHQ 的总单线态氧猝灭速率常数（k(r) + k(q)），其值分别为 5.14 x 10(7)、3.41 x 10(6)和 1.99 x 10(8)M(-1)s(-1)。在首次确定α-松油烯的 k(r)值后，通过在相同条件下测量它们与单线态氧的相对反应速率，计算出合成抗氧化剂的 k(r)值。BHA、BHT 和 TBHQ 的 k(r)值分别为 3.90 x 10(5)、1.23 x 10(5)和 2.93 x 10(6)M(-1)s(-1)。BHA、BHT 和 TBHQ 的化学猝灭与总单线态氧猝灭的百分比分配（k(r)x100）/（k(r) + k(q)）分别为 0.76%、3.61%和 1.47%。结果表明，合成抗氧化剂几乎完全通过物理猝灭机制猝灭单线态氧。这是首次报道这些合成抗氧化剂的单线态氧猝灭机制。实际应用：合成抗氧化剂，特别是 TBHQ，具有很强的单线态氧猝灭能力。本文还清楚地表明，合成抗氧化剂对单线态氧的猝灭主要是通过物理猝灭机制。结果表明，这些合成抗氧化剂，特别是 TBHQ，可实际用于保护食用油和维生素等食品成分免受单线态氧诱导的氧化，而在光照下储存时抗氧化活性不会明显损失。
