Cooling and freezing time of beef based thermal and physical properties as function of moisture content

One of the most important value that determine the quality of beef at refrigeration treatment is duration of cooling and freezing process which should be determined in advance. Mean while duration depends upon more than one factor such as initial moisture content of beef, dimention, temperature and velocity of cooling air. The objective of this paper is to study the effect of mentioned above factors on duration of one stage freezing process. This study has been based on various analyies of calculation results using a mathematical model. A computer program was developed to simulate the appropriate equations that calculate the cooling and freezing time at different conditions of moisture content of beef, temperature and velocity of cooling air. Expression the thermal and physical properties of beef as a function of its moisture content, the calculation method of refrigeration treatment duration have been given. The flow chart of the computer program has been represented. The results obtained indicate that duration of one stage freezing process could be decreased from 21 hours to 19 hours as a result of decreasing in temperature of cooling air from -25Co to -30Co at the same conditions of cooling air velocity of 4m/s, initial moisture content of beef about 0.75, beef initial temperature of 35Co, final temperature of center beef of -8Co and beef thickness of 0.20 m. In addition to that, it was found that increasing of cooling air velocity from 4 to 5m/s will cause more decreasing in duration of one stage freezing process from 19 hours to 16.5 hours at the same conditions.