Parameters Optimization And Process Improvement Of Spray Chilling For Pig Carcass

The water loss rate and surface's sensory quality of pig carcass are widely concerned by the enterprises and consumers.In this paper,Pig carcasses of Duroc x Yorshire x Landrace(DYL)were used as test materials.The spray chilling device that had already be made was used to humidify the environment,The spray uniformity of the device was improved,the spray chilling method and parameters with good effect and short working time altogether with satisfied water loss rate and sensory quality was selected,besides,the problems existed in the control system were improved,the specific work is as follows:(1)Spray chilling uniformity of the device was improved to increase the spray quantity that couldn't be fully sprayed of the carcass's surface.Nozzle type(A),distance between carcasses(B),spray time when the spray nozzle is perpendicular to the ground(C),nozzle's swing frequency of each spray chilling(D)were taken as the discussing factors,the comprehensive evaluation method was used,orthogonal test was conducted on the basis of single-factor test,the results showed that,factors that affect the spray uniformity from large to small is A,D,B,C.A had significant effect(P<0.05),and the other factors had no significant effect on the uniformity of spray.A was the outer mixing nozzle,B was 300 mm,C was 10 s,D was 2 were the optimized parameters,under such parameters,comprehensive evaluation value of 84.80 could be gotten,and the spray chilling uniformity had been greatly improved compared to 37.81 before improvement.(2)Two kinds of spray chilling methods were studied to improve the efficiency of spray chilling and shorten its working time.?Method of moisturizing carcass's surface by spray droplets into cooling space was used,carcass's abdomen was as test points to decide whether it dry or not,as a result,the law of surface water evaporate with the change of cooling time was determined and was written to the PLC control program to realize the function that water evaporation time as the spray interval time,in this way,average water loss loss of 1.25%was gotten by 10 h of spray chilling.Compared with the manual work of 1.56%,although there was a certain decrease,but the operation time is still long,and the(3)effect is not significant enough.? Segment spray chilling that high frequency of spray chilling at the early stage and later low frequency was used,and the corresponding experimental factors of total time of spray chilling with high frequency(A),interval time of high frequency spray period(B),total time of spray chilling with low frequency(C)interval time of low frequency spray period(D),single spray time(E)were selected,as a results,A had significant effect on water loss rate(P<0.01),besides,the method had a higher efficiency which could reduce the water loss rate to 1.02%at the total spray time of 7 h,so the operation time was shorter compared with the previous methods that studied.(4)The carcass's surface sensory quality should also be taken into consideration except water loss rate.The factors and levels of the segmented spray chilling method were used,by fuzzy mathematics,the quality of water loss rate,meat color and water traces of the carcass were taken as pursue indexes,after determination of the weight and membership function of all the indexes,the comprehensive evaluation results could be obtained by fuzzy operation,through range analysis,total time of spray chilling with high-frequency of 2 hours,interval time of high-frequency spray period of 9 minutes,total time of low-frequency spray chilling of 4 hours,interval time of low-frequency spray period of 40 minutes and single spray time of 10 seconds were the optimized parameters with the water loss rate was 1.07%,L*was 77.95,a was-0.05 and water traces was 2.16%,of which the corresponding membership degree was 1,0.692,0.852 and 0.884 respectively,and the comprehensive evaluation result was 0.883,which not only meet the needs of enterprises,but also had better color and less water traces.(4)The control system of the device was improved,and the following functions were realized? The optimized spray chilling parameters as the production parameters;?Adequate water and gas supply was ensured by the way of interlock between the pipelines;? Water and gas pipelines could be opened at the same time;?Spray timer window was set;? Automatic control of the air compressor was achieved;?The login interface was designed.