Study On The Drying Characteristics Of Beef Jerky Dried With Combined Mid-infrared And Hot Air

The drying characteristics of combined mid-infrared and hot air(CMIHA) drying beef jerky were studied in this paper, to provide technical support and theoretical basis for the high dehydration efficiency and quality of jerky. Firstly, the drying process of CMIHA was optimized, and then compared with mid-infrared(MI) drying and hot air(HA) drying to verify this process. Secondly, the physical properties of beef jerky and moisture mobility mechanism of beef jerky during drying was studied to explain to reveal the high quality and dehydration efficiency of CMIHA. Thirdly, drying models of beef jerky were developed, and then were programmed by VB and C# to develop the moisture prediction system during drying. Finally, based on the theoretical basis above, the continuous CMIHA drying equipment was developed, aiming to realize the high dehydration efficiency and quality of jerky. The results were as follows:The appropriate drying parameter of CMIHA was drying temperature 70℃, radiation distance 8cm, radiation intensity 0.48 W·cm-2. Then the best CMIHA drying process was compared with mid-infrared(MI) drying and HA drying, results suggested that compared with MI drying and HA drying, CMIHA drying significantly reduced(p<0.05) the drying time and energy, its time-consuming and energy-consuming were only 70% and 90% of MI drying, 40% and 22% of HA drying. Compared with MI and HA drying, CMIHA drying could significantly improve(p<0.05) the texture of beef jerky, and had better color than HA. Based on the sensory quality, jerky that dried with CMIHA could be easier accepted than that dried by MI drying and HA drying.Compared with HA drying, CMIHA drying could reduce the oxidation of myoglobin, keep the myofiber of jerky in better shape, reduce the shrinkage of myofiber and sarcomere, increase the dissolve of Z line, and make the distribution of water in surface and inside are uniformity, so as to improve the color and texture of beef jerky. Besides, CMIHA could significantly improve(p<0.05) the inside and outside temperature, improve the transverse relaxation time of immobile water(T22) and free water(T23), and accelerate the process that immobile water shifted to free water, which made the heat and mass transfer of water was in the same direction, so as to improve(p<0.05) the moisture diffusivities, accelerate the moisture mobility, and improve the drying efficiency.Modified Henderson and Pabis model was the optimal drying model of CMIHA drying on jerky in different drying distance and temperature by means of nonlinear least square based on the origin software, which R2 were all more than 0.999 and the RSS and2c value were the minimum compared with other drying models. Besides, the moisture prediction system of CMIHA drying on beef jerky was developed by programming the optimal drying models based on VB and C#, which could sufficiently predict the moisture content among CMIHA drying process of beef jerky.A continuous CMIHA drying equipment was developed, compared with HA drying equipment, this equipment could speed up muscle protein denaturation, reduce activation energy, so as to reduce the energy that jerky needed to accelerate moisture migration, and improve drying efficiency, the activation energy and time-consumption were reduced by 10.33% and 57.14, respectively, and the production efficiency was improved by two times. Besides, compared with HA drying equipment, CMIHA drying equipment could reduce the case hardening of jerky and oxidation of myoglobin, so as to make(P<0.05) beef jerky have better chewiness and color. The chewiness, shear force, shrinkage rate, a*, C* and H* of jerky dried with CMIHA were significantly higher(P<0.05) than HA, which made beef jerky have better sensory evaluation. This equipment realized the high dehydration efficiency and quality of jerky.After the production process of curing, drying, fried and packaging sterilization, compared with HA drying, CMIHA drying could significantly improve(p<0.05) the color and texture characteristic of beef jerky, increase the properties of storage, keep the traditional flavor and taste, increase the flavor of meat and roast, all of that make beef jerky have good sensory quality and improve the consumer’s purchase intention.