Study On The Preparation And Purification Of Umami Peptides From Aloididae Aloidi Protein

The present study deals with the preparation of umami peptides from Aloididae aloidi Protein with the complex protease hydrolysis. Taste characteristics of various components from hydrolysates and the mechanisms of the flavor change were studied. The amino acids composition and molecular weight distribution of the peptides were evaluated. Ultrafiltration, domestic macroporous resins chromatography, gel filtration chromagraphy and RP-HPLC were applied to the separation of umami peptides.The composition of Aloididae aloidi meat showed it contained 83.23±0.78% of moisture, 13.24±0.23% of protein (N×6.25),1.19±0.03% of fat, 1.45±0.03%of ash and 0.65±0.02% of sugar,respectively. the hydrolysates were rich in umami amino acid such as Glutamic acid, aspartic acid, alanine and glycine, and Glutamic acid had the highest percentage, account for 16.89% of the total amino acid.and flavor amino acids of Aloididae aloidi protein accounted for about half of the total amino acid, can make Aloididae aloidi meat to be the high quality materials for the Preparation of rich flavor peptide-based seasoning by giving a strong umami to Aloididae aloidi meat hydrolysates.Aloididae aloidi protein was hydrolyzed by Alcalase, Protamex, Papain, Pancreatin, Flavorzyme, and endogenous enzyme. The characteristics of these enzymes were explored and the protein utilization, the extraction rate of peptides and flavor evaluation of these hydrolysates were studied. Results revealed that Protamex and Flavorzyme hydrolysates were higher than those of others, Basing on the single factor experiments, The results show the optimal conditions for extensive hydrolysis of Aloididae aloidi meat were, feed ratio of 1:2. temperature of 55℃, the time is 6 h, pH 6.8,Protamex 3.0×104U/kg and Flavorzyme 9.0×104 U/kg, The condition under this study resulted in 61.33% of protein recovery and 45.82% of peptide recovery.The difference of flavor characteristics between Aloididae aloidi protein hydrolysates and Aloididae aloidi meat hydrolysates was studied, and the content of succinic acid in hydrolysates was Analysis, the results show that the flavor characteristics of Aloididae aloidi protein hydrolysates and Aloididae aloidi meat hydrolysates flavor characteristics were similar, there was no significant flavor difference between them, the effects of Non-protein components in hydrolysates on the umami was not significant; the content of succinic acid hydrolysis solution was far less than the taste threshold, on the enzyme solution did not affect the flavor significantly. The flavor components in Aloididae aloidi meat hydrolysates were mainly from the protein hydrolysates.Amino acids composition of hydrolysates was analysis ,and Results revealed that Glutamic acid had the highest percentage, aspartic acid, followed, account for 25.38% of the total amino acid.content of umami free amino acid in hydrolysates are much smaller than their tast threshold, so neither their umami nor sweetness can not be perceived.umani amino acid in hydrolysates existed in the form of peptides mainly,accounted for 76.41%.the umami and sweetness of hydrolysates mainly course from the Small molecular weight peptides with umani amino acid , the Subject matter is umami peptide.Molecular weight distribution of the peptides in hydrolysates was evaluated,and Results revealed that The fractions with molecular weight more than 10,000Da could be hydrolyzed by the Multiplex enzymes,hydrolysis's peptide mainly concentrated in 1,000 ~3,000 Da, and this section accounts for the largest proportion, reaching 38.16%.the molecular weight section (<3,000Da)which rich in umami peptide accounts for 47.26%,the characteristics of hydrolyzate peptide molecular weight distribution make to be a better peptide can make it to be the high quality materials for the separation and purification of umami peptide.Ultrafiltration, domestic macroporous resins chromatography, gel filtration chromagraphy and RP-HPLC were performed to purify PMHs. It was found that polar peptides had greater capacity to the umami of PMHs than non-polar peptides.and molecular weight of polar peptides in hydrolysates was mainly concentrated in <1,000 Da, which had the higher percentage in hydrolysates. Finally, the umani peptide PMHs-P2 was separated from the hydrolysates. RP-HPLC analysis showed that PMHs-P2 was divided into components of a mixture of umami peptides, and its taste threshold is about 0.125mg/mL.