Study Of Preservation Effect Of Pulse Electric Field Combined With Nisin On Prepared Beef

Prepared beef contains rich nutrients and be convenient in eating,which is complied with people's dietary demand in this rapid life tempo and includes a giant development prospect.In order to extend shelf life of prepared beef,the paper adopted non-heating processing technology of pulse electric field to deal with prepared beef and studied optimum parameter of s prepared beef handled by pulse electric field;contrasted quality of prepared beef before and after handled by pulse electric field;analyzed microbial community composition in prepared beef before and after handled by pulse electric field;studied addictive amount of natural anti-corrosive which is combined with pulse electric field in use.The major study result is shown as follows:1.The optimum parameter of prepared beef handled by pulse electric field is: pulse frequency is 30.5 kHz,duty circle is 2.3%,dealing time is 7 min,electric field is 45 kV·cm-1.Under such circumstances,the casualty of pulse electric field to prepared beef reaches 87.33%,and can reduce primary number of microorganisms of prepared beef obviously(P<0.05).Pulse electric field is feasible for non-thermal sterilization of prepared beef.2.Pulse electric field can make protein structure and performance of prepared beef changed to some extend and make color and water-retaining property of prepared beef deteriorated to some extend,tenderness improved to some extend,but this kind of change can not be felt and identified by people's perceptional senses obviously,perceptional quality change of prepared beef is not obvious(P>0.05),pulse electric field is suitable for adjusting freshness of prepared beef.3.Pulse electric field can make some low-temperature spoilage bacteria(Enterobacteriaceae,Pseudomonas)of the prepared beef passivated or in sublethal status(Brochothrix thermosphacta),which makes the low-temperature spoilage bacteria of the prepared beef become more simple.Some lactic acid bacteria strains have resistant tolerating ability to pulse electric field.After handled by pulse electric field,these lactic acid bacteria can still grow and breed under low temperature and orient corruption and deterioration of prepared beef stored at 4 ?.Meanwhile,Brochothrix thermosphacta in sublethal status after handled by pulse electric field will recover to grow during the process of storage and participate in corruption and deterioration of prepared beef.After handled by pulse electric field,shelf time of prepared beef can be extended by 3 d and reached 8 d.4.The optimum potency of joint use of nisin and pulse electric pulse is about 0.06%.After handled in nisin solution at the same potency,then to deal with prepared beef which is handled by pulse electric field,it's shelf time is extended about 7 d and reached 15 d,compared with the prepared beef which is only handled by pulse electric field not handled by nisin.