Research Of Extraction And Properties Of Peptides From Jinhua Ham

Jinhua ham is the typical example of traditional dry-cured meat products from China,that has great influence in the areas of world meat processing technology.Although it can be used as both food and medicine in traditional life,the related research on functional effects and mechanism haven't been studied.During the long fermentation ripening period,the severe hydrolysis of muscle proteins from dry-cured ham which due to the complicated physicochemical and biochemical changes,produce many small peptides and amino acids.They are closely related to the excellent quality and health benefits of Jinhua ham.Therefore,in this study,the Jinhua ham maked by traditional production process,with ripening period over one year as raw material.Crude peptides were extracted from Jinhua ham using acid dissolving and alcohol precipiting method.The emulsifying properties,antioxidant activity,ACE inhibitory activity of small peptides separated from crude peptides by ultrafiltration were investigated.Preliminary determined the peptides extracted from Jinhua ham were functional,in addition,the activities were related with peptides molecular weight.The detailed research contents and main results are shown as follows:?1?In this study,crude peptides were extracted by different solutions from Jinhua ham,evaluated for the influence of PBS ionic strength,p H and ethanol solution volume fraction by crude peptide extraction rate.The results showed that when peptides were in the condition of partial acid,it can give a best extracting effect.The suitable extraction method of the experiment was: with 0.05 mol/L hydrochloric acid?p H 1.8?as extractive agent and 50%ethanol of protein precipitation.In addition,the yield of peptides were 4.64±0.12% under the described condition.?2?The correlation characteristics of crude peptides extracted from Jinhua ham were assessed.Firstly,with polysorbate 80 as control,the emulsifying capacity?EC?,emulsifying activity index?EAI?,emulsifying stability index?ESI?,viscosity index and particle size distribution of crude pepetides were assessed to determine the emulsifying ability.The results showed that crude pepetides from Jinhua ham showed good emulsifying properties,the emulsifying properties of peptides increased signally?p<0.05?with the increase of peptide concentration.When peptide concentration reached 9mg/m L,its average EC was80.44±0.59%,reached 92.00% of Tween 80?1.5%?;when concentration greater than 3.0mg/m L,ESI reached more than 90.00% of Tween 80;with the concentration of 4.5 mg/m L,the average viscosity reached 80.01% of Tween 80?4.5%?;the average particle sizedecreased with the increase of emulsion concentration.In addition,the free radical scavenging activity,metal ion chelating ability of crude pepetides were measured and compared with GSH.The antioxidant activity results showed that crude pepetides from Jinhua ham had a strong antioxidant activity in vitro,the activity was positively correlated with concentration.The ability to remove ·OH radicals and DPPH · of peptides were similar to the GSH;Fe²⁺chelating ability was significant higher than that of GSH,while chelating rate reached more than 40%.The crude pepetides extracted from Jinhua ham did not inhibit the activity of ACE.?3?Jinhua ham extracts were separated into three fractions?fraction ? : >10 KDa,fraction?: 3¹0 KDa,fraction ?: <3 KDa?by ultrafiltration,The yield of peptide?,?,?were 23.85 ± 0.13%,11.76 ± 0.09%,55.18 ± 0.21% respectively.Each small peptide fractions were subjected to property analysis.The results showed that: fraction?,?,?had certain emulsifying performance.The emulsifying activity index and emulsifying stability index of fraction?showed the strongest;emulsifying activity index of fraction?was the highest of all.The hydrophile-lipophile balance of short peptides from Jinhua ham was less than 10,its properties was similar to lipophilic emulsifier.Inferred that the hydrophile-lipophile balance of peptides?was 8.6 9.6 which could be used as a wetting agent;the hydrophile-lipophile balance of peptides?and ? was less than 7 which could be used as a W/O emulsifier.Then,all of fraction?,?,? had strong antioxidant activity,the smaller molecular weight the stronger oxidation resistance.Especially the peptide ?with the possessed highest antioxidant activity,which hydroxyl radical scavenging activity was 35% higher than mother liquor's and Fe2 + chelating capacity was 1.3 times higher than mother liquor's.In conclusion,Jinhua ham was rich in short peptides.These small pepetides had good emulsification abilities and antioxidant activitives,but didn't show the ACE inhibitory activity.