摘要

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.