Flavour Analysis Of Egg-Based Sachima

In this article,the flavor characteristics of Sachima were analyzed,including the identification of key aroma-active compounds and the construction of aroma model of Sachima;the relationship between aroma of Sachima and shelf life;the role of egg in Sachima flavour.In order to optimizing the extraction conditions,selecting the concentration of all the compounds as the index,the result was showed that the extraction method of SPME and SAFE had better extraction effect.The single factor and response surface was performed for the optimization of SPME.According to the experimental results,The optimal condition was selecting the three coatings(PDMS/DVB/CAR)SPME fibers,weighing 6.74 g samples,pre-heating 19.8 min and extracting 40.2 min at 63.9?.The key aroma-active compounds in four egg-based Sachimas were identified and quantified using by the extraction methods of solid phase micro-extraction(SPME)and solvent-assisted flavor evaporation(SAFE),combined with gas chromatograph-olfactometry-mass spectrometry(GC-O-MS)analysis,separated by two different polar columns(DB-WAX and DB-5).In total,75 volatile compounds were identified which main contained the aldehydes and heterocyclic compounds.The sensory evaluation result was showed that the main characteristic aroma of Sachima was roasty and malty flavour.Twenty-six aroma-active compounds were revealed by calculating the retention index(RI),searching the NIST library,comparing the odor characteristics,the standard verification the aroma extract dilution analysis(AEDA).Partial least square(PLS)method was utilized to analyze the relationship between the aroma-active compounds and sensory properties and showing that the most correlations with pyrazines were those of roasted aroma,and the correlation with fresh and malty flavor was 2-pentylfuran,nonanal and octanal,propyl acetate,2-methylbutanal and 3-methylbutanal,respectively.Thirteen key aroma-active compounds which were higher than the detection limit of mass spectrometry,were quantified by external standard method in SIM mode.The final aroma model was similar with the Sachima flavour.By calculating odor activity value(OAV),the most important role in Sachima flavours were identified,including 2-methylbutanal,3-methylbutanal,hexanal,propylacetate,2-pentyl furan,nonanal and benzaldehyde played the most important role in Sachima flavour,which were provided the aroma property of cocoa,malty,cut-grass,cheesy,green bean,fat and almond,respectively.The aroma compounds in different shelf-lives Sachima were analyzed.The resultshowed that lipid oxidation is the main reaction during the storage.The content of aroma substances was increased with the extension of shelf-life.The growth rate was higher from two to four months and eight to ten months than the middle stage.The production of off-flavour substances was caused by the increase of the concentration of the existing odorant compounds,rather than the formation of substances with the undesirable smell.According to the AEDA,only FD of 3-methylbutanoic acid and hexanal were intentse,it shows that these two compounds were more correlated to the 10 months sample and off-flavor by PLS analysis.With the extension of shelf-life,the popularity of Sachima was declined gradually according to the sensory evaluation.The desirable aromas were weakened gradually,and the unpleasant odors were become more clearly.However,the unpleasant odors exited in Sachima were not particularly impacted the sensory experience,even though in 10 Months.Satisfactory flavors were still played a leading role in Sachima in the warranty period.The Sachima with different percentages(0%,10%,20%,30%)of eggs were made,the changes of aroma were explored.The research found that alcohols,aldehydes and heterocyclic compounds still account for a large proportion.With the increase of egg content,alcohols and aldehydes were decreased,on the contrary,heterocyclic compounds were increased which almostly showed roast flavor,such as nut or popcorn.Therefore,the addition of eggs' proportion contributed to the roasty aroma of whole flavour in Sachima.In addition,with the increase of egg content,the inhibition of lipid oxidation was promoted by Maillard reaction.The compounds related to the eggs are: 2-methylbutanal,3-methylbutanal,6-methyl-5-Hepten-2-one,5-methyl-2-ethylpyrazine,ethenylpyrazine,1,4-dimethylpyrazole,2-furanmethanol,1-(1H-pyrrol-2-yl)-ethanone,2,5-dimethylpyrazine,2,6-dimethylpyrazine and,2-ethyl-3,5-dimethylpyrazine.