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Effect Of Tea Polyphenols On Quality Of Chiling Fish Surimi Products And Antibacterial Mechanisms

Posted on:2012-11-21Degree:DoctorType:Dissertation
Country:ChinaCandidate:S M YiFull Text:PDF
GTID:1101330332983414Subject:Food Science
Abstract/Summary:PDF Full Text Request
Surimi products (Collichthys Fish Ball) having tremendous developing potentiality and most abundant resource was aimed in the study. Microbial profiles were analyzed, and the dominant bacteria species were isolated and identificated in storage time at 0℃. The effects of tea polyphenols (TP) on microbiological and biochemical quality of collichthys fish ball were studied. The effects of TP on the characters, membrane permeabilization, proteomics of membrane protein of bacteria were discussed. And a possible mechanism of the TP antibacterial ability was discussed through bacterial, membrane damage,The main results obtained in this study were as follows:1. TP served as the final bio-preservatives for fish surimi products (Collichthys Fish Ball). It was showed that adding TP could extend the shelf life of fish-ball, compared with the control group. Adding tea polyphenols could improve the texture of Collichthys fish ball, including increasing hardness and maintaining springiness. The freshness also could be kept at a good level, indicated by the relative low TBA, TVB-N and pH values. The 0.25 g kg﹣1 tea polyphenols addition in Collichthys fish ball VP kept good characteristics for a longer shelf life when stored under 0℃.2 In the sample with addition of TP, the population of Enterobacteriacea was the dominant bacteria during the refrigerated storage period. The count levels of Pseudomonadaceae and Micrococcaceae increased, while the other members of the microbial association remained at lower levels during the entire storage period. For the control sample, the initial population of Pseudomonads was the dominant bacteria followed by Micrococcaceae and Enterobacteriacea. Enterobacteriacea increased more rapidly than Pseudomonads in the first 5 days, and became the dominant bacteria species in the control sample.3. Five strains of typical single-colony bacteria isolated from VRBGA agar were Serratia liquefaciens, Serratia odorifera, Serratia liquefaciens, Serratia liquefaciens, and Serratia marcescen, belonging to the Serratia family. Three strains of typical single-colony bacteria isolated from Pseudomonads agar were Pseudomonas fluorescens, Pseudomonas mendocina, and Pseudomonas aeruginosa, belonging to the Pseudomonas family.4. Research of growth characters of Pseudomonas aeruginosa and Serratia marcescens showed that the bacteriostasis circle formed of P. aeruginosa and S. marcescens were significant (p<0.05), when TP concentration was beyond 0.075% and 0.0375%, respectively. TP could change the bacterial prediction model parameters, and slowed bacterial growth rate, whereas the number of bacteria in stable phrase had no significant difference. Morphology changes of bacteria treated with TP were investigated by transmission electron microscopy, indicating that the primary inhibition action of TP was to damage bacterial cell membranes, and cause cell membrane diffusion, and inaddition, the nucleoid of the bacteria were not see clearly. TP also increased the permeability of the membranes of bacteria and disrupted the cell membrane with the release of small cellular molecules. Moreover, TP could make the ATP and AKP enzyme activity decreased. The effect of TP on the total bacterial proteins was not significant, but the change of the bacterial membrane protein was significant. Furthermore, a proteomics approach based on two-dimensional gel electrophoresis and MALDI-TOF/TOF MS analysis were used to study the differences in the membrane proteins of bacteria between the TP treatment and control samples. The results showed that the differential expressed proteins identified by MALDI-TOF/TOF MS were found to be enzymes, which might induce the metabolic disorder of the bacteria and resulted in the death of the bacteria.
Keywords/Search Tags:Surimi products, Microbial profiles, antibacterial mechanism, Membrane permeabilization, Proteomics
PDF Full Text Request
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