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dc.contributorMulti-disciplinary Studiesen_US
dc.contributorDepartment of Applied Biology and Chemical Technologyen_US
dc.creatorKwong, Lap-chi-
dc.identifier.urihttps://theses.lib.polyu.edu.hk/handle/200/3293-
dc.languageEnglishen_US
dc.publisherHong Kong Polytechnic University-
dc.rightsAll rights reserveden_US
dc.titleThe effectiveness of biological preservatives and modified atmosphere packaging in preservation of Sparus macrocephalus, Pomadasys hasta and Lutjanus johnien_US
dcterms.abstractIn this study, Modified Atmosphere Packaging (MAP) and biological preservatives (Glucose oxidase and Lysozyme /EDTA /sodium chloride system) were used to investigate their effectiveness in fish preservation. Different evaluation methods were used to evaluate the fish freshness. These included sensory evaluation, microbial analysis, physical property measurement, chemical and biochemical analysis. In phase I, Black Seabream (Sparus macrocephalus) was used to undergo preservative treatments with different combinations of preservatives and MAP including the addition of Glucose oxidase (GOX) system, addition of Lysozyme /EDTA /sodium chloride system, the use of increased carbon dioxide concentration as MAP, addition of deoxidizer and their combination use. With the use of deoxidizer in preservating, lower number of colonies on agars during 21 days of storage was observed or deoxidizer could lower down the bacteria multiplication rate by absorbing the molecular oxygen in atmosphere of the package. Lower TMA content was observed during 21 days storage compared with other conditions. The sensory scores showed that the fish with deoxidizer used were still acceptable at day 14. The use of deoxidizer was chosen as the method used in phase II. Because the relatively low cost and potential usefulness in actual situation, there was reason for more investigation. In phase II, Pomadasys hasta and Lutjanus johni were used to undergo storage conditions with or without deoxidizer by using air as packaging atmosphere. The evaluation results of Pomadasys hasta and Lutjanus johni in phase II was not much better than that of the control condition in TMA, Microbial, Torrymeter and Sensory evaluations. The reason might be due to the use of the bag of deoxidizer which was opened at the time at phase I. The deoxidizer packets might become less effective as the deoxidizer had contacted air in atmosphere during the time in phase I. Lastly, Seafood Freshness Indices ( SFI) -- Fresh SFI and Threshold SFI were established for Sparus macrocephalus, Pomadasys hasta and Lutjanus johni.en_US
dcterms.extentvii, 114, [21] leaves : ill. (some col.) ; 30 cmen_US
dcterms.isPartOfPolyU Electronic Thesesen_US
dcterms.issued1998en_US
dcterms.educationalLevelAll Masteren_US
dcterms.educationalLevelM.Sc.en_US
dcterms.LCSHFishes -- Preservationen_US
dcterms.LCSHFishes -- Packagingen_US
dcterms.LCSHProtective atmospheresen_US
dcterms.LCSHFishery processingen_US
dcterms.LCSHHong Kong Polytechnic University -- Dissertationsen_US
dcterms.accessRightsrestricted accessen_US

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Please use this identifier to cite or link to this item: https://theses.lib.polyu.edu.hk/handle/200/3293