Study On The Changes Of Physicochemical Properties,Lipid Oxidation And Volatile Flavor Components Of Dry-cured Donkey Ham During Its Processing

With the development of economy and the improvement of human consumption,Donkey meat as a high nutritional value meat is being accepted by more and more consumers.Dry-cured ham is the main traditional preserved meat products in China.This study analyzed the changes of physical and chemical properties,lipid oxidation and volatile flavor components of donkey ham during seven different processing stages of its processing,which have a great effect on the formation of characteristic flavor of donkey meat ham.This study would provide the theory basis for optimizing the technology processing and quality controlling of donkey ham.Main research contents and conclusions are as follows:1.Study on the changes of physicochemical properties of dry-cured donkey ham during its fermentation processing.To analyze the changes of the physicochemical properties of donkey ham,the seven key different stages of processing were studied.The results showed that: the p H of dry-cured donkey ham keep stable(6.2-6.6)during the whole processing(p>0.05);The moisture content significantly decreased firstly(p<0.05)and finally became stable,and Na Cl content increased during processing,mainly due to the evaporation and osmosis of water;The TVB-N content keep stable and rise steadily,and peaked at 85.76 mg/100 g in mature period of ham;The ash showed a significant upward trend(p<0.05)firstly and finally became stable(p<0.05),indicating that the protein and lipid oxidation products in the processing of donkey ham were accumulating continuously and the inorganic salt content in the ham increased.2.Study on the changes of lipid oxidation of dry-cured donkey ham during its fermentation processing.To analyze the changes of the free fatty acid(FFA),TBA,POV,Carboxyl and Carbonyl group value of donkey ham,the seven key different stages of processing were studied.The results showed that: POV and TBA increased significantly firstly and finally became stable(p<0.05);The carbonyl group value was stable,indicating that the process of fat oxidation and the slow formation of flavor substances;The Carboxyl group value significantly increased after the end of curing,indicating that the increasing fat oxidation led to the continuous generation of hydroperoxides;The main FFA is linoleic acid,followed by palmitic acid,oleic acid and stearic acid.The relative content of linolenic acid in polyunsaturated fatty acids decreased most significantly during the donkey ham processing(p<0.05),indicating that linolenic acid plays a key role in the special flavor substances formation of donkey ham.3.Study on the changes of flavor components of dry-cured donkey ham during its fermentation processing.SPME and GC-MS were used to identify and analyze the changes of flavor components of dry-cured donkey ham during its fermentation processing.The results showed that: 121 flavor compounds were detected,including 21 alkenes,12 alcohols,25 aldehydes,15 acids,11 ketones and 23 esters.In the final product(mature stage)of donkey ham,the content of aldehydes is the highest(41.00%),and the content of acids(3.74%)and alcohols(5.25%)is also relatively high.The changes of these compounds in the production process are quite complex and play an important role in the formation of the final special flavor of ham.In summary,the changes of physicochemical and lipid oxidation indexes during the processing of donkey ham play an important role in the formation of the final special flavor of the ham,which provides a good theoretical basis for the processing process optimization and quality control of the donkey ham.