Changes Of Amino Acids And Fatty Acids In Preserved Egg Processing And The Role Of Forming Preserved Egg Flavor

In order to investigate the influence of fatty acids and amino acids on the flavor of preserved egg during it matured process, the paper studied the amino acids and free amino acids in preserved egg during it matured process by liquid chromatography(LC), analyzed the fatty acids and free fatty acids in preserved egg during it matured process by gas chromatography(GC). Then analyzed the volatile compounds in preserved egg during it matured process. The volatile compounds was extracted by simultaneous distillation extraction (SDE), the distillation extraction conditions was optimized and the compounds were analyzed by gas chromatography-mass spectrometry (GC-MS). The main contents, results and conclusions in this dissertation are summarized as follows:1. Liquid chromatography(LC) was used to analyzed amino acids and free amino acids in preserved egg during matured process. During preserved egg matured process, all kinds of amino acids showed decreasing trend except the protein’s glycine, which showed increasing trend. And at the beginning of pickled(0-20d) showed obviously decreasing trend, then the downward trend begin slowly(20-44d). Amino acids content of egg protein decreased from107.64mg/g to91.575mg/g, decrease of14.925%; species is reduced from17to15, arginine and cysteine(Arg and Cys) gradually disappear. The essential amino acids content decreased from51.089mg/g to40.159mg/g, with the exception of tryptophan not measured. The percentage decreased from47.463%to43.584%. The free amino acids content of egg protein increased in the curing process, but the15species remain unchanged, not containing arginine, cysteine and tyrosine(Arg, Cys, Tyr). The total amount of amino acid in preserved egg yolk decreased from142.005mg/g to99.939mg/g, reduced by29.623%, and the change law of the specices is the same as the proteins. The essential amino acids content decreased from51.089mg/g to40.159mg/g, with the exception of tryptophan(Try) not measured, but the percentage has little change, increased from the original44.697%to44.813%. The free amino acid content increased from5.481mg/g to20.023mg/g, species increased from14to15, and produced a small amount of histidine in the curing period, not containing arginine, cysteine and tyrosine(Arg, Cys and Tyr).2. Gas chromatography(GC) was used to analyzed fatty acids and free fatty acids in preserved egg during matured process. During preserved egg matured process, most of the fatty acids showed increasing trend. And at the beginning of pickled(0-20d) showed obviously increasing trend. The types of fatty acids increased from23to27, content was reduced from295.924mg/g to242.338mg/g. Saturated fatty acids (SFA) showed obviously changes, increased from the initial17.10%to64.21%, content is increased from51.111mg/g to155.61mg/g. At the same time, monounsaturated fatty acid (MUFA) and polyunsaturated fatty acids (PUFA) were decreased significantly, precentage decreased from40.28%to17.36%and from42.62%to18.44%, the concent decreased from119.217mg/g to42.069mg/g and from126.284mg/g to44.703mg/g. Among all of these fatty acids,15showed increasing trend,8showed decreasing trend,4kinds of fatty acids were increased first and then decreased. Both the species and the content of free fatty acid was increased during the pickling process. The species rise to7from13, the content is increased from21.774mg/g to102.578mg/g. SFA was the highest, accounted for43.448%, PUFA accounting for30.985%, MUFA accounted for25.566%.3. The volatile compounds in egg protein and egg yolk was extracted by simultaneous distillation extraction (SDE) under the optimal conditions, and the compounds were analyzed by gas chromatography-mass spectrometry (GC-MS). Totally65volatile flavor compounds were identified in preserved egg protein, including14hydrocarbons,4alcohols,10aldehydes,4ketones,11acids,8esters,4benzenes,3phenols and7heterocyclic compounds. During the pickled process,11compands has not been changed, including6hydrocarbons,2esters and3heterocyclic compounds. Totally147volatile flavor compounds were identified in preserved egg protein, including36hydrocarbons,14alcohols,17aldehydes,7ketones,23acids,17esters,9benzenes,1phenols,20heterocyclic compounds and3not identified. During the pickled process,6compands has not been changed, including1hydrocarbon,1aldehyde,2benzenes and2heterocyclic compounds. All kinds of compangs have significant change. Especially aldehydes, acids and heterocyclic, play an important role in the formation of the unique flavor of preserved egg.4. Amino acids and free amino acids, fatty acids and free fatty acids have a greater influence on preserved egg flavor. They are the important flavor compands, have important effects on the taste of preserved egg, at the same time, they are the precursors of volatile substances and can generate volatile compands through many reaction. Especially, they can generate heterocyclic compounds, and have an important impact on the overall flavor of preserved egg.