Comparison Of Flavor Compouds Of Chicken/Soybean Oligopeptides And Purification And Application Of Umami-flavored Peptides

Due to the limitation of resources and people’s demand for cost and nutrition,it has become an urgent need to replace some animal-derived polypeptides with plant-derived polypeptides as raw materials for the production of nutritional natural compound condiments.In this study,multiple umami peptides were identified from animal-derived chicken oligopeptides(Pc)and plant-derived soybean oligopeptides(Pb)through various separation and purification methods and LC/MS.Then,sensory evaluation and electronic tongue analysis were combined to compare the flavor characteristics and content relationship between the two ingredients.First of all,two HPLC methods was established for the determination of 4 kinds of flavor nucleotides and 4 kinds of flavor organic acids in raw materials.Zorbax Eclipse XDB C18 column was used for both methods.The mobile phase consisted of methanol-potassium dihydrogen phosphate at the flow rate of 1 m L/min.The isometric elution was performed.A UV detector was used with a wavelength of 210 nm for nucleotide detection and 254 nm for organic acid detection.The results showed that: Pc had the highest content of lactic acid(4.32%)without citric acid,while Pb had the highest content of citric acid(1.91%).The most abundant flavoring nucleotides in Pc and Pb were GMP(0.091%)and IMP(0.092%),respectively.Secondly,the component Pc-3/Pb-3 with the best taste characteristic was separated from Pc/Pb by nanofiltration.The component Fc-2/Fb-2 with the best umami effect was separated from Pc-3/Pb-3 by GFC.And the component Kc-2/Kb-2 with the best umami effect was separated from Fc-2/Fb-2 by RP-HPLC.By UPLC-MS,one 8-peptide Arg-Thr-Glu-Glu-Leu-Glu-Glu-Ala with molecular weight of 975.45 Da and one 6-peptide Asp-Pro-Ser-Asn-Ile-Lys with molecular weight of 672.34 Da were identified from Pc.By UPLC-MS,two tetrapeptides,Val-Thr-Val-Glu and Leu-Glu-Lys-Asp with molecular weight 446.24 Da and 503.26 Da,and a tripeptide,Trp-Glu-Arg with molecular weight489.23 Da were identified from Pb.At the same time,the sour,salty,umami and umami-enhancing of each component separated by Pc and Pb nanofiltration were positively correlated with the contents of malic acid,lactic acid and succinic acid;The increase of the contents of CMP,GMP,IMP and AMP could significantly improve the salty,umami and umami-enhancing of the samples,but had little effect on the sour,sweet and bitter tastes of the samples;The umami of Pc and Pb nanofiltration fractions increased with the increase of Asp and Glu contents,and the four sweet amino acids Ala,Gly,Pro and Thr also promoted the umami of the samples to different degrees.The relationship between the taste characteristics of the two raw materials and the content of the taste substances was generally consistent.Finally,the Pc nanofiltration separation component Pc-1 and soybean oil were heated in an oil bath at 110°C for 10 min to generate a shrimp paste-like aroma product,which contained 78 volatile components;the Pb nanofiltration separation component Pb-3 had obvious pain-suppressing effect.The above research made it possible to use plant polypeptides instead of animal polypeptides as raw materials for the production of natural compound flavoring,which laid a theoretical foundation and provided material base for the research and development of new nutritive natural compound flavoring.