New function of antioxidants in foods

1.调味料对抗坏血酸（AA）在100℃水溶液中的热稳定性的影响研究了在日式烹饪中常用的各种调味料的存在。本实验反应体系中AA的减少相对于AA损失浓度是一级反应。在AA溶液中加入各种调味料时，盐稳定的AA和日本含酒精的外加剂，如清酒和甜酒（米酒），对稳定性没有显著影响。相反，酱油、味噌和鲣鱼肉汤粉以浓度依赖性的方式加速了AA的下降。在日本调味料的成分中，除铁外，氨基酸也参与了AA的加速降解。研究了抗氧化剂对肿瘤坏死因子（TNF）诱导的人单核细胞U937凋亡的影响。n -乙酰半胱氨酸（NAC）、2-巯基乙醇（2-ME）、维生素E （VE）或丁基羟基甲苯（BHT）均可减轻环己亚胺存在下TNF诱导的U937细胞凋亡。抗氧化剂对细胞凋亡的抑制率为40 ~ 60%，提示抗氧化剂可部分抑制tnf诱导的细胞凋亡。在培养基中添加NAC或2-ME，并对细胞进行TNF处理后，细胞内谷胱甘肽（GSH）水平保持高于对照组（未进行抗氧化处理）。然而，当细胞用YE或BHT处理时，GSH水平保持不变。这些结果表明抗氧化剂的所有抑制作用都不能用GSH水平来解释。

1.Effects of seasonings on the stability of ascorbic acid in a cooking modelThe thermolability of ascorbic acid (AA) in aqueous solution at 100□C was assessed in the presence of various seasonings commonly used in Japanese style cooking. The decrease of AA in the reaction system of this experiment was a first-order reaction with respect to the concentration of AA loss. When each seasoning was added to AA solution, salt stabilized AA and Japanese alcohol-containing admixtures, such as sake and sweet sake (mirin), did not have a significant effect on the stability. Conversely, soy sauce, miso and broth powder from skipjack accelerated the decrease of AA in a concentration-dependent manner. Of the constituents of Japanese seasonings, not only iron but also amino acids are involved in the acceleration of AA degradation.2.Effects of antioxidants on TNF-induced apoptosisThe effects of antioxidants on tumor necrosis factor (TNF) -induced apoptosis of human monocytic U937 cells were evaluated. Apoptosis of U937 cells induced by TNF in the presence of cycloheximide was attenuated by N-acetylcystein (NAC), 2-mercaptoethanol (2-ME), vitamin E (VE), or butylhydroxytoluene (BHT). The inhibition rate of apoptosis was 40 -60%, indicating that antioxidants could play a role as a partial inhibitor of TNF-induced apoptosis. When NAC or 2-ME was added to culture medium and cells were treated with TNF, the level of intracellular glutathione (GSH) was maintained higher than the control group (without antioxidant treatment). However, when cells were treated with YE or BHT, the level of GSH remained unchanged. These results suggested that all the inhibitory effects by antioxidants are not explicable by the level of GSH.