Kosugi H, Kato T, Kikugawa K
Ferris Women's College, Yokohama, Japan.
Anal Biochem. 1987 Sep;165(2):456-64. doi: 10.1016/0003-2697(87)90296-x.
The reaction of four to eight carbon straight-chain alk-2-enals with 2-thiobarbituric acid (TBA) produced yellow 455-nm-, orange 495-nm-, and red 532-nm-absorbing pigments depending upon the reaction conditions. The 1:1 reaction of the aldehydes with TBA in 15% acetic acid at 100 degrees C produced the yellow pigment at 0.25 h and the red at 6 h. The reaction of the aldehydes with TBA in excess at 100 degrees C produced the yellow at 0.25 h, the orange at 2-6 h, and the red at 0.25-6 h. The formation of these pigments required molecular oxygen. These pigments could be separated from each other on HPLC. The red pigment formed from the aldehydes could not be distinguished from the red 1:2 malonaldehyde-TBA adduct by absorption spectrum and HPLC. The red color yield was the highest in the 1:1 reaction and retarded in the reaction with TBA in excess. The red color due to these aldehydes may contribute in part to the color formed in the general TBA test of lipid oxidation. The 1:1 reaction initially produced colorless 1:1 adducts X, which were subsequently converted into the yellow and red pigments under aerobic conditions. The reaction of the aldehydes with TBA in excess might initially produce X and then another colorless 1:2 adducts Y; the latter being converted into yellow, orange, and red pigments under aerobic conditions.
四至八个碳的直链2-烯醛与2-硫代巴比妥酸（TBA）反应，根据反应条件会产生吸收波长为455纳米的黄色色素、495纳米的橙色色素和532纳米的红色色素。醛与TBA在15%乙酸中于100℃下进行1:1反应，0.25小时产生黄色色素，6小时产生红色色素。醛与过量TBA在100℃下反应，0.25小时产生黄色色素，2至6小时产生橙色色素，0.25至6小时产生红色色素。这些色素的形成需要分子氧。这些色素可通过高效液相色谱法彼此分离。醛形成的红色色素在吸收光谱和高效液相色谱上无法与1:2丙二醛-TBA加合物区分开来。红色产率在1:1反应中最高，在与过量TBA的反应中会延迟。这些醛产生的红色可能部分导致了脂质氧化一般TBA测试中形成的颜色。1:1反应最初产生无色的1:1加合物X，随后在有氧条件下转化为黄色和红色色素。醛与过量TBA反应最初可能产生X，然后产生另一种无色的1:2加合物Y；后者在有氧条件下转化为黄色、橙色和红色色素。
