Investigation of changes in the qualitative, oxidative and microbial indices of minced and non-minced beef during the freezing storage

One of the best ways to preserve meat is to freeze it, which can keep the meat in a natural state without significant spoilage. In this regard, this study aimed to investigate the effect of storage time (1, 7, 14, 21 and 28 days) in freezing (temperature -18 ° C) on chemical properties (humidity, ash, fat and protein), oxidation indices (peroxide, Conjugated diene and thiobarbituric acid), number of psychrophilic bacteria and structure of minced and non-minced beef fatty acids. The results showed that with increasing storage time, the amount of humidity and protein decreased, but the peroxide index, conjugated diene and thiobarbituric acid increased and there was no significant change in the amount of fat and ash in the samples. However, oxidation indexes of peroxide, conjugated diene and thiobarbituric acid in minced beef were not higher than minced meat. The maximum amount of peroxide (1.2 meqO2/kg) was related to the minced meat sample during 28 days of storage at freezing temperature. Based on gas chromatographic findings, there is no difference between minced meat and minced meat in terms of short chain fatty acids C10 to C20, and the amount of n-3 and n-6 fatty acids in minced meat is higher than minced meat. The results of bacterial count showed that the number of psychrophilic bacteria in meat samples did not increase during storage of meat at freezing temperature.