Study On Drying Model And Processing Of Superheated Steam Drying Of Beef

Beef is the second largest outputs of meat foods in China.Beef which with high nutrition as raw material processing into jerky of a unique flavor and favorite in market.In this study,beef was processed by superheated steam drying(SSD)technology.The changes of beef quality and sensory structure were studied under different conditions.The optimum parameter of SSD in beef jerky was determined by combining the response surface with fuzzy mathematics comprehensive sensory evaluation method.The SSD characteristics of beef were studied and a dynamic model of beef thin layer drying was established based on nonlinear regression analysis.The numerical simulation was used to simulate the heat and mass transfer of beef during superheated steam drying.It provided a certain technical basis for the processing of beef jerky.1.Quality of beef during dryingConsidering the color,shrinkage,hardness and chewiness of beef as indicators,the changes in the sensory quality were investigated to obtain optimized parameters.As the drying time increases,the L*-value of beef continues to decrease,the hardness of beef continues to increase,the chewiness increases,and the shrinkage rate also increases.The influence of temperature on the index is more significant than the thickness of beef on the index.The results showed that each indicator had a certain regression correlation with drying time.The temperature of 125-135?,thickness of 3.5-6.5mm,and time of 30-40min would be a desirable processing the range of parameters.2.Fuzzy comprehensive sensory evaluation combine with response surface method optimize beef jerky processingThrough the research of factors such as drying temperature,beef thickness,and drying time,the Response Surface was combined with fuzzy mathematics to determine the best processing technology for beef jerky.The results showed that the value of comprehensive sensory evaluation was the highest at temperature of 130?,thickness of 5mm and drying time of 35min.The regression model was obtained by Response Surface analysis:Y=-192.80250+2.83350X1-0.57333X2+0.83617X3+0.022X1X2-(6.O×10-4)X1X3+0.022667 X2 X3-0.011X12-0.31333X22-0.0126X32The optimum parameter was the drying temperature of 132.8?,thickness of 5mm,drying time of 34.5min,and the value of comprehensive sensory evaluation was 8.4133.Verification showed that actual and predicted values were almost identical3.Research on beef drying characteristicsUnder the condition of fixed steam flow rate,the effects of different beef slice thickness and drying temperature on the drying characteristics of beef were studied.The results showed that the drying rate of beef was of several different stages,which were rapid speed,constant speed,and falling rate.The higher temperature of superheated steam,the shorter time was required for drying,and the more obvious change of the center temperature;the thicker of the beef slices,the lower drying rate would be,and the constant speed drying stage lasts longer.The data of the variation of moisture ratio with time during SSD was used to establish a thin-layer drying model of beef by 12 kinds of models which commonly used through non-linear regression fitting.The results showed that the best fitting one was the Midilli and Kucuk model.The experimental verification showed that the predicted data of the model was almost the same as the actual.Thus,it could be used to predict the moisture change during the drying process.4.Numerical simulation of beef during SSD base on the theory of heat and mass transferBased on the Fourier heat equation and the Fick's law,the heat and mass transfer processes of beef were described.A one-dimensional model of heat and mass transfer was established.It used finite difference method to simulate the change of the center temperature of beef.The change of the moisture content showed that the obtained temperature curve was in good agreement with the experimental data and was just not well accord with in the initial stage.The overall change trend of the predicted data of the moisture content change was consistent with the experimental data.