| Large yellow croaker is popular among Chinese consumers because of its good taste and rich nutritional value,and it contains a large amount of unsaturated fatty acids,which has a preventive effect on various diseases.In recent years,with the improvement of farming techniques and fishing techniques,the production of Large yellow croaker has increased year by year.In the process of transportation and storage,chilled Large yellow croaker is highly susceptible to its own and external factors,causing corruption and deterioration of fish,which not only causes economic losses,but also harms consumers' health.Therefore,it is of certain significance to study the preservation method of the shelf life of chilled Large yellow croaker.The plant essential oil is a natural plant product such as the fruit,seed,flower,root,stem,leaf,skin or whole plant of the plant,which can be directly eaten,and has the functions of aroma,flavor,seasoning and bacteriostatic.The plant essential oil monomer refers to a single compound extracted from the plant essential oil,and the plant essential oil monomer has some of the same functions as the plant essential oil.The combination of plant essential oil monomers in a certain ratio can achieve better results than single use.The main content of this paper is to explore the effect of compound plant essential oil monomer on the quality of Large yellow croaker fillets during storage.Firstly,the method of equal dilution was used to determine the MIC and MBC of 12 plant essential oils when used alone,and the plant essential oils with good bacteriostatic effect were selected,and the MIC and MBC of the main components were used alone.The plant essential oil monomer with good antibacterial and bactericidal effect is compounded with thymol and calculated FIC.Then Thymol 4.875%and Eugenol 7.81%(TE),Thymol 4.875%and Cinnamic aldehyde 3.9%(TC),Thymol 4.875%and Alpha-Terpineol 15.62%(TA)3 groups The combination of plant essential oil monomers was applied to Large yellow croaker stored at 4?.The sensory evaluation,TVC and physical and chemical indicators(pH,TVB-N and chromatic aberration)were used to investigate the quality changes of Large yellow croaker during storage.Finally,by measuring the electronic tongue,free amino acids,taste nucleotides and EUC,the taste changes of the Large yellow croaker fillets during storage in the three treatment groups and one blank group were investigated.The main findings are as follows:(1)Study on the antibacterial effect and synergistic effect of compounding plant essential oil monomers.Through the analysis of the antibacterial effect of 12 plant essential oils,the five plant essential oils such as oregano oil,cinnamon oil,spearmint oil,eucalyptus oil and thyme oil have stronger antibacterial effect than other plant essential oils.The MICs were all below 2.00 mg/mL;thymol,carvacrol,cinnamaldehyde,carvone,cinnamyl alcohol,terpinene,geraniol for three antibacterial effects on 19 plant essential oil monomers The inhibitory effect of the inoculum was stronger than that of other plant essential oil monomers,the MIC was below 2.00 mg/mL,and the antibacterial effect was good.The bacteriostasis effect of 9 groups of compound essential oil monomers was combined,and the thymol and eugenol combined.The antibacterial effect is the strongest,and the inhibitory effect on the three strains is the strongest.The FIC is 0.37,0.31 and 0.37,respectively.There is a synergistic effect between the two,thymol and terpineol compound,thymol and cinnamaldehyde compound.The antibacterial effect is strong,and the FIC values are all less than 0.5.The combination of the two groups has a synergistic effect.(2)Through the study on the preservation effect of large yellow croaker fillets during storage,the sensory score of the large yellow croaker in the TE group was the slowest,which was 34.50%lower than that of the other two kinds of compound spices.On the 12th day of storage,the TE had the highest sensory evaluation score.In the middle of storage,the brightness and whiteness values of the large yellow croaker in the blank treatment group were significantly greater than those in the compound treatment group(p<0.05).When stored on the 12th day,the highest brightness and whiteness values in the compound treatment group were TE,which was most effective for color maintenance of large yellow croaker.The TE compounding group had the best inhibitory effect on microorganisms.Compared with the blank group,the total number of microorganisms decreased significantly.The TA compounding group also reduced the total number of colonies,but the effect of reducing in the early stage of storage was not obvious.During storage,the pH value of large yellow croaker decreased first and then increased.Over time,the pH of the blank group was significantly higher than that of the compound treatment group;during the storage period,the TVB-N of the large yellow croaker There is a certain inhibitory effect,but by the end of storage,the number of microorganisms increases,and only the TE treatment group has the most significant effect.3.The sensory score of the Large yellow croaker in the TE group was the slowest,which was 34.50%lower than that of the other two kinds of compound spices.On the 12th day of storage,the sensory evaluation score of the TE group was the highest;In the middle of storage,the brightness and whiteness values of the Large yellow croaker in the blank treatment group were significantly greater than those in the compound treatment group(p<0.05).When stored on the 12th day,the highest brightness and whiteness values in the compound treatment group were TE,which was most effective for color maintenance of Large yellow croaker.(3)Through the study on the taste of large yellow croaker fillets during storage,the TE group was significantly different from the other three groups on the first and seventh days of storage.On the 10th day of storage,the plant essential oil monomer group was compounded.The taste profile of the K group is quite different.During storage,the total free amino acid content of large yellow croaker fillets showed a trend of decreasing first and then increasing.The content of umami and sweet amino acids decreased gradually with the storage time.The content of bitter amino acids increased with the storage time.On the 10th day of storage,the content of umami and sweet amino acids in group K decreased to 0.During storage,the umami and sweet amino acids of TE group were significantly different during storage than other groups,and the content of bitter amino acid was always low during storage.On the first day of storage,there was no significant difference in the nucleotide content of the samples from the TE,TA,and TC treatment groups compared with the K treatment group;on the first day of storage,the EUC of the TE group reached 6.48 mg MSG/g,relative to the TC.,TA,and K were 5.71%,8.33%,and 17.13%higher,respectively.During storage,the freshness value of group K decreased by 46.74%and 44.06%on the second and third days respectively.On the 10th day of storage,the freshness intensity of group K decreased to 0,and the freshness value of TE group during the whole storage period.Both are higher.In summary,the combination of plant essential oil monomer has synergistic effect and strong antibacterial effect,which can be used for insurance of Large yellow croaker during storage,so as to slow down the quality of Large yellow croaker during storage and prolong the shelf life of Large yellow croaker. |
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