Effects Of Storage Methods On Beef Quality

Beef is rich in protein and other nutrients,which can repair body tissue and improve disease resistance.As the third largest consumer of beef and beef products,China’s production and sales have increased gradually in recent years.Storage quality has always been the concern of beef slaughtering enterprises,production enterprises and consumers.Therefore,it is very important to study how to improve the shelf life of beef.Coating preservation technology is to cover the food surface with coating solution by dipping,brushing and other methods.After drying,it becomes a uniform film,which has the advantages of reducing the gas exchange between food and the outside air,reducing the dry consumption of food surface,and reducing the water loss.Ice temperature storage can effectively reduce the damage of freezing injury to meat quality,inhibit the life activity of enzymes and microorganisms,and prolong the shelf life.In recent years,the coating technology has been developed continuously,but most of them are used in the fresh-keeping storage of vegetables and fruits,and the application of meat products is less,and the research on the combination of ice temperature storage technology is rarely reported.Based on this,the longissimus dorsi muscle 24 hours after slaughter was used as material to store in six ways: cold tray,ice temperature tray,cold vacuum,ice temperature vacuum,cold coating and ice temperature coating,and each index was detected during storage.The purpose is to understand the quality differences of beef in various environments and provide data reference for improving the shelf life of fresh beef.The main research contents and conclusions are as follows:1.The beef within 24 hours after slaughter were stored in six conditions: refrigerated + tray(refrigerated tray),refrigerated + vacuum(refrigerated vacuum),refrigerated + coating(refrigerated coating),ice temperature + tray(ice tray),ice temperature + vacuum(ice vacuum)and ice temperature + coating(ice coating).The coating solution was konjac gelatin compound solution.During storage,p H,storage loss rate,TVB-N,TBARS and carbonyl sulfhydryl content of each group were detected regularly.The results showed that the quality of beef decreased in different degrees,p H,TVB-N,TBARS,carbonyl content increased,sulfhydryl content and water holding capacity decreased.The p H value of zangtuo group reached 6.79 and TVB-N value reached 23.28 mg/100 g after 12 days of storage,the p H value of Bing Tuo group reached 6.71 and TVB-N value reached 20.37 mg/100 g after 15 days of storage,and the TVB-N value of zangzhen group reached 20.76 mg/100 g after 15 days of storage.At the end of storage,the quality of beef could be well maintained in the ice film group and the storage film group,and the indexes in the ice temperature group were better than those in the cold storage group.The results showed that storage time,p H,storage loss rate,TVB-N and TBARS were significantly positively correlated(p<0.05 or p<0.01).Carbonyl content was significantly positively correlated(p<0.05 or p<0.01)with storage time,p H and TBARS.Sulfhydryl content was significantly negatively correlated(p<0.05 or p<0.01)with storage time,p H,TBARS and carbonyl content There was a significant negative correlation(p<0.05 or p<0.01)..2.The microstructure and moisture distribution of six groups of beef during storage were detected by scanning electron microscope(SEM)and low field nuclear magnetic resonance(NMR).The results showed that with the extension of storage time,the muscle fiber structure of beef under different storage conditions was damaged to varying degrees,resulting in the decrease of water holding capacity.The ice temperature coating technology can better maintain the water holding capacity of beef and reduce water content and loss.During storage,the content of water which is difficult to flow gradually decreases,while the content of free water gradually increases,the water holding capacity of each group was as follows: ice temperature coating group >refrigerated coating group > ice temperature tray group >refrigerated tray group >ice temperature vacuum group > refrigerated vacuum group.3.A total of 45 volatile components were detected during storage.There were 24 volatile components in fresh beef,and the main volatile components were acetone,2,3-butanedione,2,3-pentanedione,2-octanol and 1-octen-3-ol.A total of 44 volatile compounds were detected after 8 days storage,and the main volatile components were 2,3-butanedione and 2-octanol.A total of 41 volatile compounds were detected after 15 days storage.The main volatile components were 2-butanone,3-hydroxy-2-butanone,ethanol,2-ethyl-hexanol,benzyl alcohol and 2-pentylfuran.With the extension of storage time,the relative content of volatile compounds increased,and the increasing degree of volatile compounds in each group was as follows: tray group > Vacuum group > coating group,cold storage group > ice temperature group.Konjac coating combined with ice temperature preservation technology can inhibit beef spoilage caused by protein,lipid oxidation and microbial metabolic activities,so as to better maintain the flavor of fresh beef.