Zamora Rosario, Gallardo Emerenciana, Navarro José L, Hidalgo Francisco J
Instituto de la Grasa, Consejo Superior de Investigaciones Científicas, Avenida Padre García Tejero 4, 41012 Seville, Spain.
J Agric Food Chem. 2005 Jun 1;53(11):4583-8. doi: 10.1021/jf050047+.
The reaction of methyl 9,10-epoxy-13-oxo-11(E)-octadecenoate, methyl 12,13-epoxy-9-oxo-11(E)-octadecenoate, 4,5(E)-epoxy-2(E)-heptenal, and 4,5(E)-epoxy-2(E)-decenal with phenylalanine in acetonitrile-water (2:1, 1:1, and 1:2) at 80 degrees C and at different pHs and carbonyl compound/amino acid ratios was investigated both to determine if epoxyoxoene fatty esters were able to produce the Strecker-type degradation of the amino acid and to study the relative ability of oxidized long-chain fatty esters and short chain aldehydes with identical functional systems to degrade amino acids. The studied epoxyoxoene fatty esters degraded phenylalanine to phenylacetaldehyde. The mechanism of the reaction was analogous to that described for epoxyalkenals and is suggested to be produced through the corresponding imine, which is then decarboxylated and hydrolyzed. This reaction also produced a conjugated hydroxylamine, which was the origin of the long-chain pyridine-containing fatty ester isolated in the reaction and characterized as methyl 8-(6-pentylpyridin-2-yl)octanoate. Epoxyoxoene fatty esters and epoxyalkenals exhibited a similar reactivity for producing phenylacetaldehyde, therefore suggesting that nonvolatile lipid oxidation products, which are produced to a greater extent than volatile products, should be considered for determining the overall contribution of lipids to Strecker degradation of amino acids produced during nonenzymatic browning. In addition, the obtained data confirm that, analogously to carbohydrates, lipid oxidation products are also able to produce the Strecker degradation of amino acids.
研究了9,10-环氧-13-氧代-11（E）-十八碳烯酸甲酯、12,13-环氧-9-氧代-11（E）-十八碳烯酸甲酯、4,5（E）-环氧-2（E）-庚烯醛和4,5（E）-环氧-2（E）-癸烯醛与苯丙氨酸在乙腈-水（2:1、1:1和1:2）中于80℃、不同pH值及羰基化合物/氨基酸比例下的反应，以确定环氧氧代烯脂肪酸酯是否能够引发氨基酸的斯特雷克型降解，并研究具有相同功能体系的氧化长链脂肪酸酯和短链醛降解氨基酸的相对能力。所研究的环氧氧代烯脂肪酸酯将苯丙氨酸降解为苯乙醛。该反应机理与环氧烯醛所描述的类似，推测是通过相应的亚胺生成，然后亚胺脱羧并水解。该反应还产生了一种共轭羟胺，它是反应中分离出的含长链吡啶的脂肪酸酯的来源，其结构鉴定为8-（6-戊基吡啶-2-基）辛酸甲酯。环氧氧代烯脂肪酸酯和环氧烯醛在生成苯乙醛方面表现出相似的反应活性，因此表明，在确定脂质对非酶褐变过程中产生的氨基酸斯特雷克降解的总体贡献时，应考虑非挥发性脂质氧化产物，其生成量比挥发性产物更多。此外，所得数据证实，与碳水化合物类似，脂质氧化产物也能够引发氨基酸的斯特雷克降解。
