Study On Lipid Degradation In Xiangxi Bacon Processing

Bacon is a typical Chinese traditional meat products with a long history and unique flavor.Different areas of bacon have different flavor characteristics,Xiangxi bacon is mainly produced by pork,after the processing of salting,drying and smoking,it has a unique smoked flavor and good taste.Fat in the different raw materials and fat degradation in the process of bacon have a lot of impact in flavor,in order to further understand the degradation of fat in bacon processing,the effects of different raw materials,different curing methods and different baking techniques on the lipid degradation were studied.The main contents and results are as follows:(1)The changes of lipids in different parts of Ningxiang flower and hybrid pig were compared,to explore the relationship between lipid degradation and raw materials.The results show that there are many differences in the moisture content of different raw materials,the water content of the longest back muscle in Ningxiang pigs and hybrid pigs accounted for 72.47%,68.28% respectively.The decrease in moisture content occurs mainly in the baking period.Salt permeate mainly occurs in the salting period,salted efficiency of pork is less than the leg meat and the longest back muscle.Glyceride in the longest muscle and leg meat rose more than the pork.The content of phospholipids and their degradation in the process are related to varieties,phospholipid content in the leg meat and longest back muscle is higher than pork;the content of phospholipids in Ningxiang pig is lower than that of hybrid pigs,but its degradation in the process is more than that of hybrid pigs.From the changes in free fatty acid content,The fatty acid degradation of hybrid pigs is more than that of Ningxiang pigs(2)The effects of traditional dry salting method,intermittent vacuum salting method and vacuum salting method on the degradation of fat in bacon were studied.The results show that Vacuum salting or intermittent vacuum salting can reduce the loss of bacon moisture and improve the salting effect.The phospholipids decreased by 7.43%,5.32% and 5.14%,respectively,under the traditional dry salting method,intermittent vacuum salting method and vacuum salting condition,vacuum salting or intermittent vacuum salting can significantly reduce the degree of phospholipid degradation.At the end of salting,in the traditional dry salting group,the unsaturated fatty acids accounted for 47.23% of the total free fatty acids;The unsaturated fatty acids in the intermittent vacuum salting group accounted for 51.32% of the total free fatty acids;In vacuum salting group,unsaturated fatty acids accounted for 50.81% of total free fatty acids.The use of vacuum or intermittent vacuum method can reduce the oxidation of unsaturated fatty acids(3)The effects of different baking methods on lipid oxidation were compared.The results showed that :compared with low temperature baking,the use of high temperature baking can improve the salting effect.but under high temperature baking,bacon form a layer of dry film on surface,which hinder the penetration of water.The carbonyl value,diene value and TBARS value of the high temperature baking group were significantly higher than those of the low temperature group,the baking temperature had a significant effect on the oxidation rate of bacon.At the end of baking,the content of free fatty acids in the low temperature baking group was the highest,which was 20.10%;Phospholipids in the low temperature baking group hydrolyze most,which was 78.37%.The use of low baking temperature is conducive to the hydrolysis of phospholipids and low temperature baking can effectively reduce the degradation of free fatty acids.