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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 42 (1977), 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: The partition or equilibrium distribution of vinylchloride between a polymer phase (polyvinylchloride) and a contacting phase (food simulants) has been determined using n-hexane, distilled water and vegetable oil as the food simulants. The results from the respective polyvinylchloride (unplasticized)-food simulating systems showed a concentration dependent, nonlinear distribution of monomer, in favor of the polymer, with decreasing initial levels of vinylchloride for n-hexane and vegetable oil. For the unplasticized polyvinylchloride-water system, the partition coefficient was also concentration dependent but linear. The partition coefficient was constant with respect to initial monomer concentration for plasticized polyvinylchloride and the food simulants.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The enzymatic hydrolysis of lactose has been studied using β-galactosidase (Aspergillus niger) immobilized on collagen. The immobilization process employs simple and inexpensive techniques to bind the enzyme to collagen through noncovalent bond formation. The stability and reusability of collagen bound lactase membranes was evaluated in a biocatalytic modular reactor. Little or no loss in reactor activity was observed after storage for a period of 90 days. Following an initial decrease in activity, stable limit activity was maintained over a number of reactor volume replacements. The activity of the fungal lactase in both the soluble and bound states was determined in ultrafiltered acid whey. The catalytic potency of the enzyme, in both states, showed inhibited enzyme activity in acid whey, as compared to aqueous lactose. In the bound state, the enzyme experienced a partial irreversible inhibition.
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 44 (1979), 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: The problem of migration from a packaging material into packaged food is treated in the literature using extraction studies from polymeric materials into simulating solvents such as heptane, oil, water, 3% acetic acid, 50% ethanol, etc. (Figge, 1972). Such studies provide a good measure for predicting possible migration into foods, but do not serve as a direct measure for the relative affinity of foods or their components for the migrant (e.g. vinylchloride monomer, VCM). The approach taken in this study was to establish directly the relative affinities of the basic food constituents for vinyl-chloride. Sorption measurements of VCM by four basic food constituents, (water, corn oil, casein and sucrose) were conducted. In addition, sorption studies were carried out with oil in water emulsions. For water, oil, oil/water emulsions and casein, it was found that the partition coefficient values (defined as the equilibrium concentration of VCM sorbed over the equilibrium concentration of VCM in headspace) were fairly constant within the sorbate (VCM) concentrations studied. At 24°C, the partition coefficient values for oil, casein and water were 23.7 × 103, 11.7 × l03 and 2.1 × 103, respectively. Sucrose did not sorb detectable amounts of VCM under the experimental conditions employed. The sorption of VCM by an oil-in-water emulsion, representing a multi-component system, follows the same relationship to initial headspace concentration and temperature as do water and oil. The total amount of VCM sorbed by the emulsion, however, is not the exact arithematical sum of potential contributions of its individual components. Sorption studies showed that the chemical nature of the sorbent (i.e. food constituent), starting sorbate (i.e. VCM) concentrations and temperature are important factors affecting the extent of vinylchloride sorption.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The effect of structural modifications on the enzyme-binding capacity of collagen has been studied using p-galactosidase (E. coli K1 2) immobilized to collagen membranes. The immobilization process employs simple and inexpensive techniques to bind the enzyme to collagen through direct protein-protein interaction. The tertiary structure of the collagen matrix was modified by cross-linking with the difunctional reagent, glutaraldehyde, or by a natural cross-linking process associated with aging. Such modifications were found to markedly reduce the enzyme (β-galactosidase)-binding capacity of collagen films. The deleterious effect of cross-linking on the binding capacity of collagen was shown to be completely reversed by proteolytic enzyme treatment of aged films but only partly so for glutaraldehyde-treated films.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 44 (1979), 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 of vinylchloride (VCM) by dry casein particles was determined as a function of temperature and moisture content. The amount sorbed was found to increase with a decrease in temperature or reduction in moisture content of the particles. At 30° C, the partition coefficient values (Ku) were 1.05, 0.4 and 0.33 × 102 for casein particles of moisture content 3.5, 6.0 and 7.5, weight percent respectively. The partition coefficient was defined as the equilibrium concentration of VCM sorbed over the sorbate concentration in the headspace. The effect of dipole moment of the sorbate on sorption to casein was evaluated by comparing sorption of VCM and the analogues, ethylene and vinylidene chloride. Sorption was found to increase with the dipole moment of the sorbate, suggesting the importance of dipole moment as a sorption inducing factor. Further supportive evidence for the importance of dipole moment in sorbate-casein interaction was obtained by a gas chromatographic technique (inverse phase gas chromatography). Using casein as the stationary phase of a gas chromatographic column, the solutes VCM, ethylene, vinylidene chloride (VCD) and hexane were pulsed through the column and the peak shapes recorded. Peak shapes indicated an interaction between casein and the polar solutes (VCM and VDC) whereas no such interaction (sorption) was indicated for the nonpolar solutes, ethylene and hexane. A rate model for VCM sorption by dry casein particles was also developed.
    Type of Medium: Electronic Resource
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  • 7
    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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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 40 (1975), 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
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 27 (1987), S. 934-938 
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The rate of loss of the antioxidant 2-tertiary-butyl-4-methoxy phenol (BHA) from high-density polyethylene (HDPE) was determined using high pressure liquid chromatography (HPLC). The rate of loss was found to follow a first-order expression. Almost all of the antioxidant was lost (〉95 percent) within 1 day at 50°C, within 3 days at 40°C, and within 7 days at 30°C. The controlling parameter for mass transfer of the antioxidant was found to be volatilization rather than diffusion.
    Additional Material: 3 Ill.
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