| Salted duck eggs are a kind of traditional reconstituted egg products uniquely created in China.Because of their unique flavor and rich nutrition,they have great market demand in China.However,the phenomenon of "hard heart" generally exists in salted duck egg yolks,which seriously affects the salted egg yolks.The taste is reduced in quality.Therefore,in view of the problem of "hard heart" egg yolk,in this paper,the status of hard egg yolk produced under different curing factors,and by comparing the physical and chemical properties,protein structure and microstructure between hard egg yolk and surrounding egg yolk Conduct research to explore the causes of the formation of "hard heart" egg yolks.The main research contents and results are as follows:1.Use sensory evaluation methods to find out whether salted duck eggs have hard egg yolk under different curing factors.The results showed that different captive methods,freshness of duck eggs,eggshell thickness,pickling temperature,concentration of pickling liquid,cooking conditions,ultrasound-assisted curing will appear hard heart egg yolk,but the sensory evaluation is slightly different.2.By comparing the physical and chemical properties,microstructure,protein composition and secondary structure between the hard heart egg yolk and the surrounding egg yolk,the difference between the two egg yolks was studied,and the reasons for the formation of the hard heart egg yolk were initially investigated.The results show that the physical and chemical properties of the hard heart egg yolk and the surrounding egg yolk are different.The moisture,salt,fat p H,soluble protein and sulfhydryl content of the hard heart egg yolk are less than the surrounding egg yolk,and the protein content is higher than the surrounding egg yolk;the protein group of the hard heart egg yolk Neither the sub-structure nor the secondary structure changed significantly,but the microscopic results showed that the hard heart egg yolk particles had aggregated.3.The chemical analysis method is used to reveal the dynamic changes of the physical and chemical characteristics of the hard heart egg yolk by comparing the changes of various indicators during the curing period of the hard heart egg yolk and the surrounding egg yolk,and combined with the previous research content to explore the reasons for the formation of the hard heart egg yolk.The results show that the change of moisture is the main reason for the formation of hard heart egg yolk.During the curing,the moisture of hard heart egg yolk decreased by 15%,and the solidification of egg yolk accelerated to increase its hardness;in addition,the change of protein also caused the formation of hard heart egg yolk The reason is that the protein content of the surrounding egg yolk decreased from 20.5% to 17.8%during curing,while the content of the hard heart egg yolk increased from 16.2% to 24.5%,indicating that the protein of the surrounding egg yolk agglomerated to the hard heart egg yolk,which led to the formation of a "hard heart". |
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