Effect Of High Pressure Combined With Thermal Treatment On Taste Compounds And Flavorof Pork

Compared with traditional thermal treatment,high pressure is a cold sterilization technology that can effectively inactivate harmful microorganisms and extent the shelf life in food,with little damage to nutrition and sensory quality of food.At present,the study of high pressure treatment in meat mainly focused on improving the meat tenderness and extending the storage period,with few researches on its taste and flavor.And it is a trend that high pressure combined with thermal treatment are applied together in meat products in the future.Therefore,in the hope of providing a theoretical basis for its further application in meat products,the longsissimus pig muscles were used in the study,firstly,the effect of high pressure combined with thermal treatment on taste compounds and flavor of pork were studied from the microscopic perspective,and then the whole taste and flavor of the samples were studied using electronic tongue and electronic nose from macroscopic perspective,respectively.The specific research contents and results were as follows:1.Effect of high pressure combined with thermal treatment on taste compounds of pork To investigate the effect of high-pressure combined with thermal treatment on free amino acid,nucleotide and degradation products,thiamine,reducing sugar and fatty acids of pork,the longsissimus muscles were treated under a pressure range of200~600MPa and a temperature range of 20~60°C for 10 min,and the whole taste of samples was compared by electronic tongue.Results showed that the pressure,temperature and their interaction had extremely significant effect(p<0.01)on the total content of amino acids,nucleotides and their degradation products,and thiamine.After high pressure combined with thermal treatment compared,the free amino acid content in most samples changed significantly(p<0.05)compared with the control group;in addition to the sample treated by 200MPa-40?,the total content of nucleotides and degradation products in other treatedsamples were increased markedly,and the main degradation product was IMP;the thiamine content of each treated group was significantly(p<0.05)lower than that of the control group,the thiamine content changed significantly(p<0.05)with the increased temperature at the treatment of200 MPa and 600 MPa,while had no significant change at 400 MPa.After high pressure combined with thermal treatment,the reducing sugar content in pork were lower than that of the control group,but only the temperature had significantly effect(p<0.05).High pressure combined with thermal treatment had not a significant effect on the fatty acid composition of total lipids.Analysis of Partial Least Squares Regression(APLSR,PLS2)showed that the effect of pressure and temperature on the taste of samples were comparative.Measuring from the fatty acids point of view,600MPa-60? processing sample had better flavor,and 400 MPa processing samples had better nutritional values.The results of electronic tongue showed that the more severe the treatment conditions were,the more of samples' whole taste changed;when treated with 200 MPa or400MPa,temperature had a marked effect on the taste of samples,while when treated on 600 MPa,the role of temperature was very limited.2.Effect of high pressure combined with thermal treatment on flavor of pork To investigate the effect of thermal combined with high-pressure treatment on flavor of pork,the longsissimus muscles were treated under a pressure range of 200~600MPa and a temperature range of20~60°C for 10 min.Then the flavor of samples was analyzed by GC-MS and electronic nose,respectively.The results showed that a total of 141 volatile flavor compounds were identified in different samples,including aldehydes,ketones,alcohols,esters,acids,alkanes and so on.Compared with the control group,both the number of compounds and the total peak areas of the treated samples were increased,especially in the samples treated by600 MPa,23 kinds of compounds was increased;and the total peak areas were increased with the increase of temperature or pressure,which mainly resulted from aldehydes,ketones and alcohols,especially pentanal,hexanal,3-hydroxy-2-butanone,2,3-octanedione,pentanol,1-octen-3-ol and so on.Analysis of PLS2 showed that the effect of pressure on flavor was bigger than that of temperature;and the more severe the treatment conditions were,the more of samples' flavor changed.The results of electronic nose showed that the samples treated with 600 MPa had a very different flavor from other samples.Both PLS2 and electronic nose can better distinguish samples.3.Pressure was the major factor affecting the flavor of pork when treated with high pressure combined with thermal,the pressure should be controlled around 400 MPa,and the effect of temperature on flavor was small,so according to the actual condition it may be controlled between40 ? and 60?,in order to kill some of the barotolerant microbesin meat.