Research On The Production Process And Drying Kinetics Of Beef Jerky Microwave-hot-air Coupling Drying

Beef jerky is a kind of Chinese traditional dried meat product popular among the consumers because of its unique taste and easy storage.Due to the thick fiber of the beef and the backwardness of the drying process of beef jerky,its quality is rather poor.Therefore,in this study,papain is as a tenderizer to improve the tenderness of beef,and the microwave-hot air coupling drying process is used to solve the problem of poor quality caused by the traditional drying process.At the same time,the dynamics of microwave-hot air coupled dry beef is also carried out in this study to take a real-time prediction and control of moisture changes during the drying process of beef jerky.The main findings are as follows:1.The best process for the tenderization of beef by papain is testfied.By measuring the indexes such as the shear force,the content of hydroxyproline and myofibril fragmentation index(MFI),the effect of the concentration,treatment time and treatment temperature of papain on beef tenderness is investigated.The process of papain's effect on beef tenderness is optimized by response surface analysis to carry out the optimum tenderization process:papain concentration 16 mg/kg,treatment time 60 min,treatment temperature 55? under such a condition,beef shear force is 42.5 N,which is very close to the predicted 42.8 N,with a deviation of 0.71%,indicating that the beef tenderization process determined under the model will be a significant guiding in actual production.The result of the scanning electron microscopy showes that papain has obvious dissolution effect on beef connective tissue and muscle fiber,which could be used to effectively improve beef tenderness.2.Combined with the fuzzy mathematic sensory evaluation method,the single-factor and response surface design experiments are designed to optimize the microwave-hot air coupling drying process of beef jerky.The weight analysis of sensory quality of microwave-hot air coupled dried beef jerky is performed based on sensory evaluation method.The obtained weight set is X={color,smell,taste,tissue state}={0.16,0.20,0.33,0.31}.The established regression model shows that the optimum process conditions of the microwave-hot air coupling drying process of beef jerky are:hot air temperature 75 0C,drying time 5 min,microwave power 250 W,under which the sensory score of beef jerky product is 8.33,with a deviation of 1.22%from the predicted 8.23.It is indicated that the combination of fuzzy mathematic sensory evaluation and response surface is feasible for the microwave-not air coupling drying process of beef jerky.Based on the optimization results of microwave-hot air coupled drying process of beef jerky,the effects of microwave power,hot air temperature and beef slice thickness on the drying quality of beef are studied,and a drying kinetic model is established.The results show that the rate of water coefficient decreases firstly and then increases during the drying process.The Lewis,Henderson and Pabis and Page models are used to fit the drying curve during the coupling drying process,with a result of the correction coefficient of the Page model is significantly higher than the others and that it is of smallest standard deviation.The Page model is selected to fit the microwave-hot air coupled dry beef process,and its kinetic model is determined:moisture coefficient(MR)=exp[-exp(-6.642+0.007P+0.029T-14.231 L)*t1.971].Under the same test conditions(microwave power 250 W,hot air temperature 75 ?,slice thickness 15 mm),the fit between the Page model and the experimental values is rather better,indicating that the Page model is more suitable for describing the variation of water during the microwave-hot air coupled drying process.This study can provide a theoretical basis for the control of moisture content of microwave-hot air coupled dry beef jerky.4.By controlling the moisture content of the beef jerky products obtained from different drying processes at the same level(45.62%±0.34),the quality difference between different dried beef jerky products is analyzed comprehensively.The results show that the color and texture characteristics of microwave-hot air coupled dried beef jerky are significantly better than those of other drying processes(P<0.05);the shear stress and volume shrinkage of microwave-hot air coupling drying beef jerky are significantly lower than the indexes of hot air drying(P<0.05);hot air drying better preserves the internal muscle fiber structure of beef,and microwave drying has great damage to the internal muscle fiber structure of beef so that hot air-hot air coupled drying could significantly improve the damage of muscle fiber structure caused by microwave drying,and furthermore,under the action of microwave,it can significantly improve the T2 relaxation time of the non-flowable water and enhance its fluidity;both microwave drying process and hot air drying process cause great loss of the original flavor of beef,but the microwave drying can give the product a good roasting flavor,and the microwave-hot air coupling drying preserves a better flavor substance of beef and can also give the beef jerky a better roasting flavor.Therefore,the microwave-hot air coupled dry beef jerky process gives a better quality to the beef jerky.