Discrimination Of Digestion Properties Of Proteins From Three Types Of Dry Cured Ham In China

Dry cured ham is a traditional meat product with high quality which has a long history,high nutritional value and good sensory characteristics,so it is deeply loved by the majority of consumers.Dry cured ham is also an important source of high bio-valuable proteins because it contains the essential amino acid composition and proportions that the human body needs.However,due to the different dry cured ham has different processing characteristics,such as the length of processing time,traditional and modern processing technology and the different processing environment that caused by the different origins,which will have an impact on dry cured ham's nutritional value,and thus affect its digestion and absorption in the human body.But it still lacks a systematic study on in vitro digestion of protein in dry cured ham in three major producing areas of China.The objectives of the present study is to investigate the three major influencing factors that concludes the different origin(Jinhua,Rugao,Xuanwei),different processing time(one year of processing,two years of processing,three years of processing)and traditional and modern processing technology on in vitro digestion of protein and digestion products of three types of the dry cured ham in China.The study applied the in vitro model which simulated the gastrointestinal digestion and regarded food nutrition as the main point of entry.At the same time,the study used the related technologies of the proteomics.So this study can provide a theoretical basis for the processing method of dry cured ham,the evaluation of nutritional value and the reasonable consumption of consumers.1.A comparative study on digestion properties of protein in dry cured ham in different producing areas and processing timeDry cured ham from three major producing areas in China and of three different length of processing time for each producing area was investigated in this study.In vitro digestion model was employed for the simulation of gastrointestinal digestion in the human body,and in vitro digestion experiments were carried out for dry cured ham with different characteristics.Digestibility,as well as the digestion products of selected dry cured ham,was analyzed and identified based on technologies related with the proteomics and peptidomics.The results demonstrated that Xuanwei ham exhibited the highest digestibility regardless of whether its processing time was one year,two years or three years,and exhibited the lowest particle size.At the same time,digestibility varied with different processing time and producing areas.According to the results of SDS-PAGE,degradation of protein in dry cured ham from different areas of each processing time had significant difference.At the same time,there were differences in the types and quantities of digested products of dry-cured hams made by different processing time in three different origins and three different origins in different processing times identified by LC-MS/MS,respectively.LC-MS/MS analysis revealed that Rugao ham with one year of processing,Jin hua ham with two years of processing and Xuanwei ham with three years of processing had the greatest number of 800-3500 Da Mw peptides in digested products.For ham with different processing time,digestion properties of the dry-cured ham from each place were different.Jin hua ham with two years of processing,Rugao ham with one year of processing and Xuanwei ham with two years of processing exhibited the highest digestibility and lowest particle size.According to the results of SDS-PAGE,degradation of protein in dry cured ham from different processing time of each area had significant difference.At the same time,LC-MS/MS analysis revealed that Jin hua ham with two years of processing,Rugao ham with one year of processing and Xuanwei ham with three years of processing had the greatest number of 800?3500 Da Mw peptides in digested products.2.A comparative study on protein digestion properties of Jinhua ham in traditional and modern processIn vitro digestion model was applied to simulate the gastrointestinal digestion,and proteomics technologies were also employed.For example,a nano liquid chromatography system coupled with LTQ Orbitrap(Nano LC-LTQ-Orbitrap XL MS/MS)was used for the analysis and identification of digestion products of Jinhua ham in traditional and modern process.The results showed significantly higher protein digestibility and lower particle size in Jinhua ham with modern process than that with traditional process,no matter whether it went through one step of pepsin digestion or two-steps combination of pepsin and trypsin digestion.As demonstrated by SDS-PAGE,optical density of most protein bands of ham with traditional process was significantly higher than that with modern process before enzymolysis was carried out(P<0.05).Meanwhile,significantly lower optical density was observed in most protein bands of ham with traditional process than that with modern process after pepsin digestion(P<0.05).Furthermore,LC-MS/MS analysis revealed differences in type variation and quantity of digestion products between Jinhua ham with two kinds of process.More peptides were obtained through enzymolysis from Jinhua ham with traditional process than that with modern process.