Effect of temperature fluctuation during superchilling storage on the microstructure and quality of raw pork

The effect of different temperature fluctuations on the microstructure and quality of pork loins during superchilling storage was investigated. Based on the dynamic monitoring of ice crystal formation and melting in pork through cryomicroscope, the changes of ice crystals in pork were observed at different temperature points, and there was no obvious phase transition in pork at -3 °C for a short period of time, but the freeze-thaw cycles were obviously found in the samples of -3 ± 3 °C and -3 ± 5 °C groups. Results of microstructure observation showed that temperature fluctuations resulted in muscle fiber fracture and the decrease of water holding capacity of superchilling pork, where stronger temperature fluctuation showed more significant changes. The temperature fluctuation groups exhibited higher thiobarbituric acid reactive substances (TBARS) values after 20 days of storage, and contributed to the reduction of immobilized water and the increase of free water in raw pork, and had more serious drip loss. These indicated that increased temperature fluctuation promoted lipid oxidation and drip loss of pork during storage. This study provided supports to precise temperature control in cold chain logistics of raw meat.