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  • 1980-1984  (5)
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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 45 (1980), S. 0 
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Active site binding of vinyl chloride monomer by polyvinyl chloride has been demonstrated in 2 of 3 unplasticized resins, by equilibrium partitioning studies. The magnitude of this effect was less than what was observed in previous studies. The potential for active site binding to be a limiting, factor for the migration of indirect food additives may thus depend upon chemical and morphological features of the particular resin used to manufacture the food contact article. Inverse phase gas-solid chromatographic studies have also shown active site binding in the unplasticized resin sample studied by this method. Simple dissolution was shown to be the predominant mode of monomer/polymer interaction, for the plasticized counterpart of this resin. These studies have shown the potential for obtaining reliable data for interaction of polymer resins with indirect food additive type molecules by this more quickly performed technique.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 46 (1981), S. 0 
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A novel gas chromatographic procedure was used to obtain the water sorption isotherms of sucrose and glucose. The method allows calculation of partial pressure of water and water uptake directly from a chromatogram. The isotherms developed are in a water activity range well below that of conventionally developed isotherms.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 47 (1982), S. 0 
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Sorption/desorption studies of VCM in the systems PVC/VCM/water, PVC/VCM/corn oil an PVC/VCM/heptane were carried out. At low VCM concentrations, classical curves are obtained, where the sorption isotherms are located below their desorption counterparts. Above a certain VCM concentration a crossover exists and an inversion of the curves occurs. It was suggested that the intersection between the curves represents the point where all the active sites in the polymeric matrix are occupied by monomer molecules. The negative values of the total Gibb's free energy and the energy of mixing in the polymer were found to increase with the decrease in monomer concentration pointing out to the possibility that at low enough monomer concentrations no migration of VCM into the contained food from a PVC package may occur.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food processing and preservation 4 (1980), S. 0 
    ISSN: 1745-4549
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Migration from polymeric packaging materials to containd foods is essentially a desorption process involving low molecular weight species in a polymeric matrix. Such desorption can affect both intrinsic quality and safety of ingested packaged food. A legalistic problem also exists because of present regulations of “zero tolerance” where a possible migrant is a potential carcinogen. The precise elucidation of desorption, at extremely low levels of initial migrant concentration, has thus become a major issue. However, desorption at such levels has not been adequately studied.Sorption/desorption studies conducted with food simulating solvents and foods in classical phase distribution systems shows marked concentration dependence for certain poly (vinyl chloride) resins. The thermodynamic relations between selected monomer/polymer systems have been further studied by inverse phase gas chromatography for both poly (vinyl chloride) and poly (acrylonitrile) and some of its copolymers. Results from these studies suggest that entropic relations are dominant at such low levels for transport.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food processing and preservation 5 (1981), S. 0 
    ISSN: 1745-4549
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The interaction between acrylonitrile and an acrylonitrile-styrene copolymer was studied by the use of Inverse Gas Chromatography (IGC). The Gibb's free energy, the ethalpy and entropy were calculated from the chromatographic data. It was found that the negative value of the free energy increases with the decrease in temperature and that the negative value of the heat of adsorption increases with the decrease in the amount of ACN injected into the gas chromatograph. These results indicate that the polymer-monomer interaction increases with the decrease in temperature and monomer concentration pointing to the possibility that at very low monomer concentrations no migration may occur, at ambient temperatures, from a package made of the studied polymer.
    Type of Medium: Electronic Resource
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