Influence of alternating magnetic field on the quality of beef and its protein during cold storage

Abstract

Magnetic field is an appropriate physical field, it can be used as a process parameter for the preservation of meat products. In this study, fresh beef was subjected to an alternating magnetic field of 2 mT during cold storage at 4°C, then microbial indicators, physicochemical properties of beef samples and its protein indicators were investigated. The results showed that the alternating magnetic field could inhibit the microbial growth on beef sample, and TVB-N content, drip loss and characteristic putrefactive amine were lower than the control. The total bacterial count and TVB-N value of beef samples in the control exceeded the threshold value on the 8th day, respectively, while the samples in the alternating magnetic field exceeded the threshold value on the 13th day. Meanwhile, it demonstrated that the field could delay the transformation of free amino acids to biogenic amines and inhibit the accumulation of bitter amino acids, so maintaining its nutritional characteristics. With the extension of storage period, the sulfhydryl content of beef myofibrillar proteins subjected to alternating magnetic field was lower than that of the control. It demonstrated that the protein oxidation of samples was inhibited, which would also be the reason the Ca 2+ -ATPase activity of myofibrillar proteins was maintained at a low level during the period. Furthermore, the upward trend of carbonyl group content was delayed. It provides a reference for the application of alternating magnetic field on cold storage of meat.

Effect of Static Magnetic Field on the Quality of Pork during Super-Chilling Storage

“…The TVBN value of the control was reported to exceed the threshold value of 15 mg/ 100 g [34] on day four of storage (16.87 mg/100 g), whereas the super-chilled storage under the magnetic field condition significantly prolonged the freshness period of the pork. Simultaneously, Zhang et al [27] found that the freezing under alternating magnetic field at 2 mT was able to retard the TVBN increment in beef.…”

“…The TVBN value was analyzed using the method of Zhang et al [27] with minor changes. A grounded meat sample (10 g) was put into a conical flask containing distilled water (75 mL) and the mixture was shaken for half an hour, which was then filtered using a filter paper (two layers).…”

“…During the super-chilling storage, the pH value of pork in all groups decreased first and then increased. The pH value decreased at the initial stage of storage, which may be due to the anaerobic metabolism of glycogen decomposition to produce lactic acid [48,49], and the decomposition of ATP and creatine phosphate to produce acidic substances [27]. In the process of growth and metabolism, microorganisms can decompose nutrients such as sugars into organic acids [50], which will lead to a decrease in pH value.…”