Research On The Technology, Preservation Of Extruded Pork Jerky And Its Changing Law Of Water Content During The Whole Production Process

Jerky products are considered as a kind of popular leisure food. Previous researches on extruded meat had acquired breakthrough in solving technical bottlenecks during the processing of traditional jerky, but various drawbacks still exist :(1) Beef is used as materials of their study, although the extrusion principle is universal, the extrusion process is not suitable for pork as there are significant differences between beef and pork;(2)Moisture content, an important control parameter for the whole production process and final product quality index, was showed to follow dynamic changes during meat extrusion process, it had played as a decisive role to the final quality of meat products. Therefore, mastering the changing law of material moisture during the whole process is a key index to achieve its engineering production.(3)Compared with traditional meat products, our study is a new kind of meat jerky with special storage characteristics. Water activity is the key factor affecting its storage stability, however, its control conditions are not clear. In addition, the preservation method of low water activity meat is old and inconvenient, which had affect the market acceptance a lot.In order to solve the above mentioned problems, the moisture content during meat extrusion process was taken as the main target of our research while optimizing extrusion process parameters of squeeze dry pork and developing new extruded meat products. Therefore, the variation of material moisture during the whole process and the quality control mechanism of extruded jerky were studied and analyzed afterwards. Finally, combined with researches on eating quality of meat and its storage properties, the preservative effect was studied using cinnamaldehyde sustained release in corrosion package during meat preservation based on the study of storage stability of extruded jerky with different water activity,To master the basic technical laws for this study, the effect of pork extrusion process parameters on the degree of the quality index of the extruder were optimized, including barrel temperature, screw speed and moisture content. Hence, final optimization extrusion parameters of pork jerky were achieved: ? zone barrel temperature was 148.45 ?, screw speed was 162.57 r min, and moisture content was 40.32% in raw materials, therefore, the degree of meat tissue under these conditions was up to 2.20. At the same time, squeezed dry pork xylitol without sugar was developed for the needs of special populations, and xylitol obtained optimal concentration was 25%. Furthermore, researches and development of uniform quality, nutrient-rich, low cost and unique flavor extruded vegetables jerky can be mechanized as continuous production, squeeze plum meat.Combined with the moisture content of materials, Aw with moisture status was studied and analyzed according to the variation of material moisture during the whole process and quality control mechanism of the extruded jerky, it turned out that moisture content decreased in general according to different materials in different approach from pretreatment to final drying process; the drying process prior to extrusion processing of materials was in constant drying stage, if the meat was controlled to be dried to a moisture content around 30%, then it was easy to post-processing; The moisture content of extruded material was adjusted to 40% before the material can be well organized, and the content of free water and normal water content of the material was also decreased, but the water content of the material is increased due to reaction and evaporator near the die on extruder; Since the die mouth slightly puffed and uniform quality, the drying time of extruded meat required is much shorter than traditional meat, so the drying process of pork jerky can be described in squeeze formula: y=0.0007x2-0.3492x+54.863. Moisture and materials is closely bonded to each other especially in drying process so as to reach the first critical point of water of significant drying eventually(drying time was 120 min with the moisture content around 18%). It can be used to control drying process to improve final quality of related meat products.In addition, it was found that the variation of the moisture content, Aw, and T2 integral area of LF-NMR in the whole process of squeeze dried pork was consistent overall, which had the following relationship:(1)Aw was decreased following the decrease of water content, and there was an exponential relationship(relationship: y = 0.1388e6.0381x).(2)The water content of raw materials had a linear relationship with the total T2 integral area of LF-NMR(the relationship is: y = 145.57 x + 2997.2). In conclusion, the water changes during the whole process of extrusion pork had certain rules and the interrelated process affect the changes of moisture content, which was assumed to decide the final quality of the product.Finally, the study on the storage characteristics of extrusion dry pork showed that the Aw of jerky had greater impact on the texture and storage stability. Aw=0.824 can be used as the security Aw control points in the storage of extruded pork dry. In this study, the self-made antimicrobial active packaging-cinnamic aldehyde-?-CD inclusion complex sustained anti-corrosion package achieved good application effect(but it affected by influencing the product aw) on the preservation of low water activity(Aw) extruded jerky. Meanwhile, secondary pollution for the squeeze dried pork was avoided and the level of food safety was improved due to less chemical preservatives added.