The Influence Of Different Processing Methods And Sterilizeation On The Ttorage Quality Of Roast Whole Lamb And The Exploration Of Safety Evaluation System

Roast whole lamb is the unique flavour of meat product in Xinjiang and it is favoured by the people. However, the sales and promotion of the roast whole lamb has been affected by the out-dated method of production, short storage time and quality changes of roast whole lamb during storage. In this study, two packaging materials(i.e. aluminum foil and PA/PE/ CPP bags) and the condition temperature of 121oC was used to study the influence of three kinds of sterilization time(i.e. 10, 15 and 20 min) on the sensory, colour difference value and other volatile flavour substances. In addition, the total number CFU of commercial roast meat, pathogenic bacteria, benzopyrene and other food safety indicators were also compared. Subsequently, the best packaging material and sterilization time were selected to investigate the changes in the sensory, physical, chemical and health indicators of two different processing methods of roast whole lamb under the optimal condition for 60 days. The aim of this study was to address the influence of short storage time, packaging material and sterilization time on the storage quality of roast whole lamb. The results of this study were as follows:(1) The food safety indicators conducted on the commercially roast whole lamb reported that the total number of colonies in freshly baked roast whole lamb, baron, small baron, roast small baron, desert sheep were 583.33±1139.15cfu/g, 471.67±42.62cfu/g,140±14.14cfu/g,525±52.82cfu/gand178.33±20.41cfu/g,respectivel y, which were in line with the national standards. Furthermore, the pathogenic bacteria and coliform bacteria were negative in all samples above. The benzopyrene content in the skin of roast whole lamb was nearly 21-fold than that of the meat of roast whole lamb(2.386±0.20?g/kg vs 0.112±0.01?g/kg).(2) By studying the influence of two different types of vacuum packaging materials and three different kinds of sterilization time on the eating quality, it was found that the values of L*, a* and b* of roast whole lamb after 20 min sterilization time were closer to the colour difference of freshly roasted whole lamb. In addition, the QDA sensory analysis for each treatment group roast whole lamb showed that with increasing sterilization time, there was a big difference in the aroma, meat taste and chewiness in roast whole lamb using PA/PE/CPP bag. While there was no much difference in all the sensory indicators using aluminum foil bag; the sterilization time of 15 min gave a better appearance, chewiness and aroma of roast whole lamb. The analysis of volatile flavour compounds on roast whole lamb showed that the total volatile flavour compounds in freshly roast whole lamb and the roast whole lamb packaged in aluminum foil that sterilized for 10, 15 and 20 min were 32, 32, 57 and 42, respectively. While the total volatile flavour compounds in the roast whole lamb packaged in PA/PE/CPP bag that sterilized for 10, 15 and 20 min were 23, 39 and 28, respectively. The analysis of the total number of colonies for 60 d storage period found that the control group was 74333±927cfu/g. The total number of colonies for the roast whole lamb packaged in aluminum foil that sterilized for 10, 15 and 20 min were 827±31cfu/g,347±15cfu/g and 290±10cfu/g,respectively. While the total number of colonies for the roast whole lamb packaged in PA/PE/CPP PA/PE/CPP bag that sterilized for 10, 15 and 20 min 850±50cfu/g,827±31cfu/g and 827±31cfu/g, respectively.(3) Using the best packaging material and sterilization time, the influence of two different processing methods on the quality changes of roast whole lamb was studied. The results were as follows: the maximum values of TVB-N for the roast whole lamb in pickle and paste were 50mg/100 g and 40mg/100g;the a maximum values of acidity for the roast whole lamb in pickle and paste were 8mg/g 6mg/g; the maximum values of TBA for the roast whole lamb in pickle and paste were 0.05mg/kg and 0.04mg/kg;no significant changes in pH and hardness for both different processing methods.(4) Using the production process of baron roast whole lamb as the standard, the hazard analysis was conducted on each process during the roasting of whole lamb and the corresponding critical control points was determined. Thus, the safety evaluation system for the production process of roast whole lamb has been established.It can be concluded that from the above results, the safety indicators of commercially sold roast whole lamb are in line with the national standards. The combination of aluminum foil packaging material and sterilization time of 15 min has performed better than the other combination groups in other indices. The physical and chemical indicators of the storage quality for 60 days in the roast whole lamb in paste are better than the roast whole lamb in pickle. Therefore, when the roast whole lamb in paste is prepared using the aluminum foil and sterilized for 15 min, it is regarded as the optimal production method.