Spray chilling with different frequency period for reducing weight loss and improving surface color of pig carcass

Abstract: The evaporation of moisture on the surface of pig carcass results in its weight loss during the cooling process, which leads to great economic loss to the enterprises. The purpose of this study was to solve the problems that the water loss rate of pig carcasses is high within 24 h for high body temperature in early stage, and the traditional operation of spray chilling needs more time, as well as the effects of spray chilling on meat color of pig carcass are lacked in the existing related articles. The spray chilling technique of high frequency at early stage and later low frequency was used, the effects of spray parameters on water loss rate, L* value and a value of pig carcasses were discussed, and the linear regression equation of water loss rate with the spray parameters was established as well. The results showed that, the order of importance of the spray parameters which affected the water loss rate from high to low was total time of spray chilling with high frequency, interval time of high frequency spray period, interval time of low frequency spray period, single spray time, and total time of spray chilling with low frequency; the total time of spray chilling with high frequency had extremely significant effect on the water loss rate (P<0.01), and the single spray time, interval time of high frequency spray period and interval time of low frequency spray period had significant effect on the water loss rate (P<0.05); the order of importance of the spray parameters which affected the L* value from high to low was total time of spray chilling with high frequency, interval time of low frequency spray period, interval time of high frequency spray period, total time of spray chilling with low frequency, and single spray time, and that affecting the a value was total time of spray chilling with high frequency, interval time of high frequency spray period, interval time of low frequency spray period, single spray time, and total time of spray chilling with low frequency. Total time of spray chilling with high frequency had extremely significant effect on L* value (P<0.01) and significant effect on a value(P<0.05), while other parameters had no significant effect on L* value (except interval time of low frequency spray period) and a value. The linear regression equation of water loss rate with the spray parameters was established. According to the equation, on the condition that the total time of spray chilling with high frequency was 2 h, the single spray time was 10-20 s, the interval time of high frequency spray period was 5-9 min, the total time of spray chilling with low frequency was 4 h or even shorter, and the interval time of low frequency spray period was 30-50 min, the water loss rate within 24 h was 1%, the L* value was 72-78, and the a value was -0.5-3, which not only met the demand of cutting down the water loss rate, but also could get a better meat color of pig carcass; the total time of spray chilling of 1-5 h could be saved compared with the traditional technique. This research can provide a reference for the selection of spray chilling method and parameters.