Extraction And Identification Of Fermented Beef Ham-derived Peptides

An intense proteolysis by adding various enzymes result in an accumulation of free aminoacids and peptides during the process of ham producing. In this context, the purpose of thiswork was to investigate the biological activities of peptides derived from fermented ham.1. According to the manufacture method of fermented beef ham developed by ourlaboratory, the selected beef sirloin of high quality was fermented by Bacillus licheniformis andLactobacillus plantarum. Full fermented meat after further dried, cold smoked, sliced andpackaged was manufactured into the laboratory developed fermented beef ham.2. There are two possibly suitable extraction methods of the peptides of fermented ham，according to the extraction methods of various materials at home and abroad，several key stepsof which was investigated. Comprehensive analysis was done to find the suitable extractionmethod of the peptides of fermented ham by RP-HPLC and ACE inhibitory activity assay.Combining with the actual situation, the optimal extraction method of fermented ham-derivedACE inhibitory peptides was determined, with advantage of simple extraction procedure,economical and practical, and the strongest ACE inhibitory activity of peptides extract, andapplied in the subsequent research.3. Extracts of commocially available A, B, C and D ham were detected peptides byRP-HPLC. The results of ACE inhibitory activity of the peptides derived from four kinds of hamshowed that these peptides had no ACE inhibitory activity. But the peptides isolated fromlaboratory developed fermented beef ham showed the ACE inhibitory activity of80%.4. The study aimed to investigate the stability of fermented beef ham-derived ACEinhibitory peptides after heat treatment、 room temperature storage and a simulatedgastrointestinal digestion. The results indicated that, the fermented beef ham-derived ACEinhibitory peptides after incubated at50,72,85,100℃for5min and100℃for5,10,20,40min,the ACE inhibitory activity of treatment and control groups had no significant difference. Storedat room temperature for2days, the ACE inhibitory activity of treatment and control groups hadno significant difference（P>0.05）, but when the third day, the ACE inhibitory activity of thetreatment group was significant inferior to the control group（P <0.05）, then there was nosignificant influence on ACE inhibitory activity for further storage. The ACE inhibitory activity of the peptides was treated by a simulated gastrointestinal digestion, compared with the controlgroup, have no significant difference.5. The ACE inhibitory peptides in Laboratory developed fermented beef ham was extracted, thendetection and separation by RP-HPLC, collecting special peaks (peak A and B) suspected ofACE inhibitory activity. The ACE inhibitory activity of peak A and B were69and33%,respectively. The two peaks were separated by preparation RP-HPLC, and dissolved in deionizedwater after freeze-drying. Finally the amino acid sequence of the ACE inhibitory peptides in thetwo fractions was identified by mass spectrometer. The peptides in fraction A may be an cyclicpeptide consists of four Leu or Ile, and in fraction B may be an dipeptide dehydrationcondensated by Leu or Ile.