Discrimination Of In Vitro Digestion Of Proteins From Meat Products

Meat and meat products contain high-value proteins,minerals and vitamins.Meat has been known as an important source for human nutrition,which is benificial to balance nutrition and human health.Consumption of meat and meat products increased with the increasing income.Different processes could induce meat proteins to different changes.It is recognized that protein oxidation and aggregation during processing.During cooking collagen gelling caused digestibility decreased and changed the protein profiling.However,few are known about the effects of different processing on muscle protein changes.This study was to investigate the difference in protein digestibility among different processed meat products.Different meat products were homogenized and incubated with pepsin alone or followed by trypsin.A nano liquid chromatography system coupled with LTQ Orbitrap(Nano LC-LTQ-Orbitrap XL MS/MS)was applied to characterize peptides.Different processing methods had a significant influence on protein structure and nutrition value.1.Difference on in vitro protein digestibility among four meat productsThis study was to investigate in vitro digestibility of four meat products.Dry-cured ham,cooked ham,cooked emulsion sausage and dry-cured sausage were homogenized and incubated with pepsin alone or followed by trypsin.The digestibility and particle sizes of digested products were measured.The digestion products were identified with a nano liquid chromatography system coupled with LTQ Orbitrap(LC-MS/MS).The results showed the highest digestibility and the lowest particle size for dry-cured ham(P<0.05),while the opposite was for smoked cooked ham(P<0.05).LC-MS/MS analysis revealed the highest level of methionine oxidation in dry-cured ham,it is due to the oxidation took place during ripening for dry-cured ham.2.Effects of processing on in vitro digestibility of pork proteinCooked pork,emulsion sausage,dry-cured pork and braised pork were homogenized and incubated with pepsin alone or followed by trypsin.The digestibility and particle sizes of digested products were measured.Sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE)was performed to characterize the total protein profiles.The digestion products were identified with a nano liquid chromatography system coupled with LTQ Orbitrap(LC-MS/MS).The results showed the highest digestibility and the lowest particle size for emulsion sausage(P<0.05),while the opposite was for braised pork(P<0.05).Bands on SDS-PAGE gels have significant difference pre-and post-digestion.After pepsin digestion,cooked pork,emulsion sausage,dry-cured pork and braised pork respectively had 38,87,44 and 48 specific peptides.And after trypsin digestion,cooked pork,emulsion sausage,dry-cured pork and braised pork respectively had 78,49,59,73 specific peptides.LC-MS/MS analysis revealed braised pork samples had the greatest number of 800?3000 Da Mw peptides in digested products,while the opposite one was for emulsion sausage.