(E)-2-庚烯醛对半胱氨酸-木糖体系美拉德反应产物的影响

摘要

研究了脂类氧化产物(E)-2-庚烯醛对L-半胱氨酸与D-木糖组成的美拉德反应体系热反应产物的影响.加入(E)-2-庚烯醛时,热反应产物在294 nm和420 nm处的吸光值均增大.采用固相微萃取结合气质联用法对不同模型体系热反应挥发性产物进行分析,结果表明,添加(E)-2-庚烯醛的美拉德反应产物中含氮、含硫化合物的形成受到抑制,一些硫醇类、噻吩类、噻唑类等硫化物的含量都有一定程度的减少,尤其是2-甲基-3-呋喃硫醇、2-糠硫醇、3-甲基噻吩和2,5-噻吩二甲醛的含量明显下降.随着(E)-2-庚烯醛含量的增加,生成了一些新的烷基噻吩类,如2-已基噻吩、2-(1,l-二甲基乙基)-噻吩和5-甲基-2-噻吩甲醛等.并且与对照相比,加入(E)-2-庚烯醛的体系新增了一些的醇类、酮类和酯类物质.%The effect of ( E)-2-heptenal on Maillard reaction products was investigated by thermal reaction systems consisting of L-cysteine and D-xylose.The Maillard reaction products derived from the ( E)-2-heptenal-contai-ning model systems showed the increase in absorbance at 294 nm and 420 nm, suggesting that more intermediates and browning products produced in the reaction systems.The volatiles generated in different reaction mixtures were analyzed by solid-phase microextraction (SPME) coupled with gas chromatography-mass spectrometry (GC-MS).The results showed that the addition of (E)-2-heptenal had a suppressing effect on most of nitrogen- and sulfur-containing compounds derived from the reaction between cysteine and xylose, especially for 2-methyl-3-furanthiol, 2-furfurylthi-ol, 3-methylthiophene and 2 ,5-thiophenedicarboxaldehyde.However, some new alkyl-thiophenes were formed with a concomitant increasing content of ( E )-2-heptenal, including 2-hexyl-thiophene, 2-(1,1-dimethylethyl)-thiophene and 5-methyl-2-thiophenecarboxaldehyde.Compared with the control, new alcohols, ketones and esters were formed in ( E)-2-heptenal-containing reaction system.