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  • 1
    Electronic Resource
    Electronic Resource
    Gas chromatographic study of sorption of vinylchloride by unplasticized polyvinylchloride: Effect of concentration, temperature and polymer particle size (1985)
    Oxford, UK : Blackwell Publishing Ltd
    International journal of food science & technology 20 (1985), S. 0 
    Details
    ISSN: 1365-2621
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The interaction of vinylchloride monomer with unplasticized polyvinylchloride is studied by inverse gas chromatography. The effect of monomer concentration, tem-perature and polymer particle size are particularly examined. The specific retention volume (V°g) of VCM was taken as the parameter of the PVCNCM interaction and was found to be dependent upon monomer concentration, polymer particle size and temperature. V°g increased exponentially at very low monomer concentrations, in-creased with decreasing resin particle size and decreased with increasing temperature. For a given resin particle size the effect of temperature on V°g is a lot more pronounced than the effect of particle size for a given temperature.Values for thermodynamic parameters calculated and peak shapes recorded are indicative of an exothermic, spontaneous interaction between PVCNCM, and support the ‘active site’ hypothesis which limits potential migration of the monomer from the polymer into a food contacting phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.1985.tb01953.x
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  • 2
    Electronic Resource
    Electronic Resource
    Water sorption isotherms of crystalline raffinose by inverse gas chromatography (1989)
    Oxford, UK : Blackwell Publishing Ltd
    International journal of food science & technology 24 (1989), S. 0 
    Details
    ISSN: 1365-2621
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The interaction of water with crystalline raffinose was studied by inverse gas chromatography. Water sorption isotherms were constructed at 30, 35, 40 and 50°C with water activity (aw) values between 0.0 and 0.7. Experimental data were successfully fitted to the BET, GAB and Freundlich equations and the monolayer and sorptive capacities of raffinose were calculated. These values were found to be lower than the corresponding literature values for other sugars and were attributed to the high degree of crystallinity of raffinose. The thermodynamics of the above interaction were further studied by application of the Zimm-Lundberg cluster theory. Results indicate a strong tendency for water molecules to cluster even at relatively low water activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.1989.tb00689.x
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  • 3
    Electronic Resource
    Electronic Resource
    SORPTION OF VINYLCHLORIDE ONTO POLYVINYLCHLORIDE BY CLASSICAL PARTITION AND INVERSE GAS CHROMATOGRAPHY: COMPARISON OF TWO METHODS (1985)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food processing and preservation 9 (1985), S. 0 
    Details
    ISSN: 1745-4549
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Sorption of vinylchloride onto Polyvinylchloride was studied using both classical partition and inverse gas chromatography. The effect of temperature, polymer particle size and monomer concentration were particularly examined. Data from both methods showed that at very low concentrations, the monomer was strongly retained by the polymer with equilibrium distribution in favor of the polymer increasing as concentration decreased. Increase in temperature resulted in increase of the kinetic energy of VCM molecules hence desorption was thermo-dynamically more favored than at lower temperatures. Decrease in polymer particle size resulted in a greater binding of the monomer by the polymer, due to uncovering of additional active sites in the polymer. Values for the thermodynamic parameters calculated using the two methods were in fair agreement. Results were in accordance with the active site hypothesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1745-4549.1985.tb00722.x
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  • 4
    Electronic Resource
    Electronic Resource
    Comparison of Dialysis and Metal Precipitation Effects on Apple Pectins (1992)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 57 (1992), S. 0 
    Details
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Metal precipitation as a purification method for pectins was investigated for effects on chemical composition (anhydrogalacturonic acid, methoxyl and degree of esterification and neutral sugars), and molecular properties (molecular weight and intrinsic viscosity) in comparison with dialysis. The Cu(II) ions were used to separate pectins from non-uronide components, and then the Cu(II) ions complexed with pectins were removed by 1% acid alcohol or EDTA treatment. The contaminants were removed more effectively by metal precipitation than dialysis. Acid alcohol did not affect degree of esterification of pectins, whereas it significantly cleaved the neutral sugar side chains. Pectins treated with acid alcohol had lower molecular weights, but larger intrinsic viscosities indicating their more linear nature compared to pectins treated with EDTA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.1992.tb11293.x
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  • 5
    Electronic Resource
    Electronic Resource
    Sorption/Desorption of VCM in PVC Selected Food Simulants Systems (1982)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 47 (1982), S. 0 
    Details
    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
    URL: http://dx.doi.org/10.1111/j.1365-2621.1982.tb07649.x
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  • 6
    Electronic Resource
    Electronic Resource
    Study of water sorption of flours (wheat and soy) using a hygrometric method: effect of relative humidity during heat treatment (1997)
    Springer
    Zeitschrift für Lebensmittel-Untersuchung und -Forschung 204 (1997), S. 369-373 
    Details
    ISSN: 1431-4630
    Keywords: Key words Water sorption ; Wheat flour ; Soy flour ; Heat treatment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract  The moisture sorption isotherms of wheat and soy flours at 30 °C were constructed using the Novasina hygrometric technique. Wheat flour had a higher sorptive capacity than soy flour, as has previously been demonstrated using a chromatographic sorption technique. Good agreement was found between the Novasina and the static gravimetric methods. The difference between the two methods was of the order of 10.7% for wheat flour and 11.4% for soy flour. Subsequently, the flour samples were heat treated at 100 °C for 1 h and 150 °C for 2 h at various relative humidity environments (0.32〈a w〈0.90). Sorption data showed a reduced sorptive capacity for both flours for all heating conditions which further decreased with increasing relative humidity values during heat treatment. The decrease in wheat flour sorptive capacity upon heating in the presence of moisture ranged between 11.5% and 55.7% (heating for 1 h at 100 °C) and between 42.1% and 83.1% (heating for 2 h at 150 °C). For soy flour, the decrease in sorptive capacity ranged between 7.8% and 33.8% (heating for 1 h at 100 °C) and between 45.4% and 60.6% (heating for 2 h at 150 °C). Results were correlated with the effect of a specific heat treatment/relative humidity on protein and carbohydrate constituents of the flours.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002170050092
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  • 7
    Electronic Resource
    Electronic Resource
    Effect of microwave heating on the migration of dioctyl adipate and acetyltributyl citrate plasticizers from food grade PVC and PVDC/PVC films into ground meat (1999)
    Springer
    Zeitschrift für Lebensmittel-Untersuchung und -Forschung 208 (1999), S. 69-73 
    Details
    ISSN: 1431-4630
    Keywords: Key words Dioctyl adipate ; Acetyltributyl citrate ; Plasticizers ; Migration ; Microwave heating
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract  Migration of dioctyl adipate (DOA) and acetyltributyl citrate (ATBC) plasticizers from plasticized poly(vinyl chloride) and poly(vinylidene chloride/vinyl chloride) films into ground meat of varying fat content (3%, 12%, 30%, 55%) during microwave heating has been studied. The plasticizer migrating into ground meat was determined using an indirect gas chromatographic method after saponification of the ester-type plasticizer (DOA or ATBC) and subsequent collection of the alcohol component of the ester, namely 2-ethyl-1-hexanol and 1-butanol, respectively. Identical unwrapped microwave heated (control) samples were also analysed for DOA and ATBC content. Migration was dependent on heating time, fat content of the meat and the initial concentration of the plasticizer in the film. Migration of DOA and ATBC into ground meat did not reach equilibrium after heating for 4 min at full power even for meat samples of high fat content (55%). Migration values of DOA and ATBC into ground meat of 55% fat content after 4 min of heating in a microwave oven were 172.39 mg/kg (14.62 mg/dm2) and 17.24 mg/kg (0.62 mg/dm2), respectively. Migration into control samples was below the detection limit of the method employed (〈2 mg/kg for DOA and 〈2.5 mg/kg for ATBC).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002170050378
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  • 8
    Electronic Resource
    Electronic Resource
    Effect of microwave versus conventional heating on the migration of dioctyl adipate and acetyltributyl citrate plasticizers from food grade PVC and P(VDC/VC) films into fatty foodstuffs (1999)
    Springer
    Zeitschrift für Lebensmittel-Untersuchung und -Forschung 208 (1999), S. 429-433 
    Details
    ISSN: 1431-4630
    Keywords: Key words Dioctyl adipate ; Acetyltributyl citrate ; Plasticizers ; Microwave heating ; Migration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract  The effect of microwave heating versus conventional heating on the migration of dioctyl adipate (DOA) and acetyltributyl citrate (ATBC) plasticizers from plasticized poly(vinyl chloride) (PVC) and poly(vinylidene chloride/vinyl chloride) (P[VDC/VC]) films into pizza and frankfurter-type sausages has been studied. Microwave heating was carried out with and without a susceptor. The plasticizer migrating into the food was determined using an indirect gas chromatographic method after saponification of the ester-type plasticizer (DOA or ATBC) and subsequent collection of the alcoholic component of the ester, namely 2-ethyl-1-hexanol and 1-butanol, respectively. The extent of migration of both plasticizers into pizza and sausage followed the sequence: heating in conventional oven 〉 microwave heating with a susceptor 〉 microwave heating without a susceptor. The amounts of DOA that migrated into pizza and sausage were 105.12 mg/kg and 85.01 mg/kg during conventional heating, 75.52 mg/kg and 47.69 mg/kg during microwave heating with a susceptor and 51.42 mg/kg and 37.98 mg/kg during microwave heating without a susceptor, respectively. The amounts of ATBC that migrated into pizza and sausage were 31.18 mg/kg and 25.37 mg/kg during conventional heating, 7.73 mg/kg and 7.02 mg/kg during microwave heating with a susceptor and 6.25 mg/kg and 5.17 mg/kg during microwave heating without a susceptor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002170050442
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  • 9
    Electronic Resource
    Electronic Resource
    Gas chromatographic studies on the compatibility of PVC with a migration resistant plasticizer (1991)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 192 (1991), S. 81-91 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Technik der inversen Gaschromatographie (IGC) wurde zur Untersuchung der thermodynamischen Mischbarkeit (Verträglichkeit) von niedermolekularem Poly(vinylchlorid) (PVC) mit einem Poly(adipinsäureester) als Weichmacher angewendet. Die thermodynamischen Polymer-Weichmacher-Wechselwirkungsparameter wurden aus den chromatographischen Retentionsdaten verschiedener, niedermolekularer flüchtiger Substanzen als mobile Phase auf einer stationären Phase aus Polymer-Weichmacher-Mischungen, die sich über den gesamten möglichen Zusammensetzungsbereich erstreckten, ermittelt. Die Untersuchungen wurden im Temperaturbereich von 90 bis 110°C durchgeführt. Der Flory-Huggins-Wechselwirkungsparameter (χ+23) hängt dabei im wesentlichen von der chemischen Natur der als “Sonde” verwendeten flüchtigen Substanz (mobile Phase), von der Temperatur und von der Zusammensetzung der Polymer-Weichmacher-Mischung (stationäre Phase) ab. Die Ergebnisse deuten auf eine relativ gute Polymer-Weichmacher-Verträglichkeit über einen weiten Zusammensetzungsbereich (bis ca. 70 Gew.-% Weichmacher) hin; die Verträglichkeit ist damit besser als bei früheren Untersuchungen mit hochmolekularem PVC.
    Notes: The technique of inverse gas chromatography (IGC) was used to investigate the thermodynamic miscibility (compatibility) of low molecular weight PVC-poly(adipate ester) plasticizer mixtures. The polymer-plasticizer thermodynamic interaction parameters were determined from chromatographic retention data for various low molecular weight volatile solutes (probes) on stationary phase mixtures which covered the entire composition range for each component. Experiments were carried out in the temperature range of 90 to 110°C. The Flory-Huggins interaction parameter (χ+23) values were found to be dependent on the chemical nature of the probes, the temperature, and the composition of the mixed phase. The results predict a relatively high polymer-plasticizer compatibility for a wide range of polymer-plasticizer mixtures (up to approx. 70 wt.-% of plasticizer). Results were also compared to our own previous data using high molecular weight PVC.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1991.051920107
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