本文为了探讨不同结构改性（氨基酸顺序改变、增加鲜味氨基酸、串联肽）与美拉德反应对鲜味二肽（Asn-Pro和Ala-His）鲜味与增鲜效果的影响，利用电子舌分析了Asn-Pro和Ala-His及其结构改性后获得的新肽和美拉德反应产物的呈味特性，评价了Asn-Pro和Ala-His结构改性前后以及美拉德反应对味精（MSG）和酱油的增鲜效果。结果表明，Ala-His序列改性后获得的新二肽His-Ala的鲜味评分由4.09分上升到5.08分，对MSG和酱油具有明显的增鲜作用，其鲜味评分分别提高了1.40分和0.48分，而其他结构改性获得的9条新肽（Pro-Asn、Glu-Asn-Pro、Asn-Pro-Glu、Asp-Asn-Pro、Asn-Pro-Asp、Asn-Pro-Asn-Pro、Ala-His-Ala-His、Asn-Pro-Ala-His和Ala-His-Asn-Pro）相对于原二肽的鲜味均有所下降，对MSG和酱油具有明显的鲜味抑制作用。美拉德反应可显著提升Asn-Pro和Ala-His的鲜味特性，其鲜味评分分别由7.65分和4.09分上升到9.48分和6.37分，美拉德反应产物对MSG和酱油具有明显的增鲜作用，MSG的鲜味评分分别提高了3.96分和2.29分，酱油的鲜味评分分别提高了3.77分和1.49分。氨基酸序列改变、增加鲜味氨基酸以及串联肽能显著影响多肽鲜味及增鲜效果，美拉德反应是提升多肽鲜味与增鲜效果的有效途径。

The effects of different structural modifications (the change of amino acid sequences, addingumami amino acid residues, cross-connection of the twodipeptides) and Maillard reaction for dipeptides (Asn-Pro and Ala-His) on umami intensities and umami-enhancing effect were investigated. Electronic tongue was used to evaluate the taste characteristics and the umami-enhancing effects on MSG and soy sauce. The results showed that, compared to Ala-His, the umami score of the new dipeptide His-Ala increased from 4.09 to 5.08. His-Ala had a significant umami-enhancing effect on MSG and soy sauce and their umami scores increase by 1.40 and 0.48, respectively. However, compared to Asn-Pro and Ala-His, the umami intensities of the other 9 new peptides (Pro-Asn, Glu-Asn-Pro, Asn-Pro-Glu, Asp-Asn-Pro, Asn-Pro-Asp, Asn-Pro-Asn-Pro, Ala-His-Ala-His, Asn-Pro-Ala-His and Ala-His-Asn-Pro) decreased, and they had significant umami-inhibiting effects on MSG and soy sauce. Maillard reaction could significantly improve the umami intensities of Asn-Pro and Ala-His. The umami scores of Asn-Pro and Ala-His increased from 7.65 and 4.09 to 9.48 and 6.37, respectively. In addition, Maillard reaction products of Asn-Pro and Ala-His had significant umami-enhancing effects on MSG and soy sauce, and their umami scores of MSG increased by 3.96 and 2.29, the umami scores of soy sauce increased by 3.77 and 1.49, respectively. The change of amino acid sequences, addingumami amino acid residues and cross-connection of the twodipeptide could significantly affect the umami taste and umami-enhancing effect of peptides. Maillard reaction could be an effective way to enhance the umami taste and umami-enhancing effect of peptides.

国家科技部星火计划项目（2015GA780077）；广东省教育厅特色创新项目（2019GKTSCX054）