环境温度波动幅度对冻藏牛肉水分分布与品质的影响

Effects of Temperature Fluctuations of Storage Environment on Moisture Distribution and Quality of Frozen Beef

冻藏是牛肉长时间保藏的主要方式。设计组装了冻藏环境温度波动控制装置,应用低场核磁共振、质构分析等技术,研究冻藏环境温度波动幅度对牛肉水分分布与品质的影响。结果表明:冻藏期间实测的冻藏环境温度波动范围与理论值一致。新鲜牛肉的横向弛豫时间T2值范围分别为T2b(0.1~10 ms)、T21(30~60 ms)、T22大于100 ms。冻藏环境温度的波动幅度((-18±0.1)℃、(-18±2)℃)显著影响解冻牛肉的横向弛豫时间T2的峰总面积及结合水、不易流动水的峰面积占峰总面积的比例,以及结合水、不易流动水的峰值出现的时间。环境温度波动幅度直接影响冻藏牛肉核磁成像的水分含量分布。冻藏期间环境温度波动的幅度对牛肉的红度值影响不显著,而显著影响解冻后牛肉的黄度值。环境温度的波动幅显著影响牛肉解冻后汁液流失率、牛肉的咀嚼度,对解冻牛肉的pH值无影响。

Frozen storage is the main way to preserve beef for a long time.A device for controlling the temperature variation of storage environment was developed.The effect of the range of temperature fluctuations on the moisture distribution and quality of beef was investigated by low-field nuclear magnetic resonance and texture analysis.The results showed that the measured temperature fluctuation range of the frozen environment was consistent with the theoretical value,the transverse relaxation time T2 range of fresh beef was T2b (0.1~10 ms),T21 (30~60 ms),and T22 (more than 100 ms),respectively.The total area of transverse relaxation time T2 of beef,the ratio of peak area of bound water and immobilized water to total peak area was significantly affected by the range of fluctuation of ambient temperature ((-18±0.1) ℃,(-18±2) ℃),the time when the peak of the combined water and immobilized water appeared was also influenced by the range of temperature fluctuation.The moisture content distribution of beef could be visualized by nuclear magnetic resonance imaging.The range of environmental temperature fluctuations during beef storage had no significant effect on the redness value of beef,while it had significant effect on the yellowness value of beef.The fluctuation of ambient temperature significantly affected the juice loss rate and the chewiness of beef after thawing,while had no effect on the pH value of thawed beef.