Effect Of Static Magnetic Field Assisted Controlled Supercooling-point Storage On Quality Of Beef

Beef is a high quality food source for human nutrition because of its high value protein,B vitamins,minerals,trace elements and other bioactive compounds.In the 1990 s,China's beef production entered a stage of rapid development,increasing from 1.2560 million tons in 1990 to 7.17 million tons in 2016,with an average annual increase of 281,900 tons.With the extension of time after slaughter,fresh beef may deteriorate due to its own enzyme action and microbial contamination in the process of storage,transportation and sale,thus losing its edible value and commercial value.This not only brings huge economic losses to meat products enterprises,but also may cause food poisoning and seriously harm consumers' health.Therefore,in this study,beef was used as experimental material to study the effects of static magnetic field(SMF)on its freezing parameters,to explore the effects of static magnetic field-assisted controlled supercooling-point temperature storage on beef quality,and to reveal the effects of static magnetic field-assisted controlled temperature storage on beef water retention and protein physical and chemical properties.The specific experimental results are as follows:1.Based on the dynamics and thermodynamics of food freezing and combined with the theory of electromagnetic biological effect,the effects of static magnetic field with different intensification on the parameters of beef freezing were studied to determine the optimal static magnetic field-assisted ice point temperature storage process parameters,and to clarify the effect of SMF on inhibiting the formation of ice crystals during superice temperature storage.The experimental results showed that SMF treatment had a significant effect on the initial nucleation temperature of significant beef.Compared with the control group,the initial nucleation temperature of beef was decreased by 3 ? at 7.98?8.15 m T magnetic field intensity,and SMF significantly increased the supercooling degree of beef under the condition of no significant difference in phase transition temperature.The time-temperature curve showed that the phase transition of beef in the control group occurred at the third hour of storage at-4 ?,while the phase transition of beef in the control group did not occur at the super-ice temperature assisted by static magnetic field(7.98-8.15 m T),and the non-frozen beef was maintained during the whole storage period.2.The changes of sensory and physical and chemical quality indexes of beef during storage(0,4,8,11,12 d)at 4 ?,-4 ?,-18 ? and-4 ?+SMF were analyzed.The results showed that-4 ?+SMF could effectively inhibit the formation of ice crystals and avoid freezing damage of beef under low temperature storage conditions.Compared with-4 ?and-18 ? control groups,the juice loss rate of-4 ?+SMF treatment was lower,and the sensory quality of beef hardness and color was better maintained.At the same time,-4 ?+SMF delayed the deterioration of beef quality.At the 14 th day of storage,The TVB-N content and TBARS value of beef treated at-4 ?+SMF were 12.68 mg/100 g and0.441 mg/kg,respectively,which were significantly lower than 19.056 mg/100 g and 0.721mg/kg of beef treated at-4 ?+SMF.-4 ?+SMF treatment combined the advantages of low temperature and non-freezing storage,avoided ice crystal damage to beef fiber structure,maintained the fresh taste of beef,and effectively delayed the deterioration of beef quality during storage.3.The effects of 4 ?,-2 ?,-4 ?,and-4 ?+SMF storage on water retention and myofibrin structure of beef were studied to reveal the mechanism of static magnetic field-assisted ice point temperature storage on water retention.The results showed that-4 ?+SMF could inhibit the formation of ice crystals at low temperature(-4 ?)and avoid the destruction of myofibrin by ice crystals.Compared with 4 °C-4 ° C + SMF samples of myofibril protein surface hydrophobicity and lower degeneration degree,at the same time,effectively delay beef protein oxidation in the process of storage,significantly reduce muscle water,juice loss and centrifugal liquid loss,better maintain the super points of beef in the process of storage water retention and the integrity of the myofibril protein.