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  • 1
    Electronic Resource
    Electronic Resource
    Electrochemical studies of niobium chlorides in superdry acetonitrile: electron-transfer-induced ligand-exchange reactions (1988)
    s.l. : American Chemical Society
    Inorganic chemistry 27 (1988), S. 1956-1963 
    Details
    ISSN: 1520-510X
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ic00284a025
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  • 2
    Electronic Resource
    Electronic Resource
    Electrochemistry of niobium(IV) and tantalum(IV) complexes: ligand additivity in d1 octahedral complexes (1986)
    s.l. : American Chemical Society
    Inorganic chemistry 25 (1986), S. 831-834 
    Details
    ISSN: 1520-510X
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ic00226a021
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  • 3
    Electronic Resource
    Electronic Resource
    Storage Stability of α-Tocopherol in a Dehydrated Model Food System Containing Methyl Linoleate (1981)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 46 (1981), 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: The storage stability of α-tocopherol in a dehydrated model food system containing methyl linoleate was evaluated. The degradation rate of α-tocopherol was best described by zero order kinetics with rates significantly greater than 0 (p≤0.002), correlation coefficients (|R|)≤0.88 and standard deviations from 4–13% of the reported rate constants. The zero order rate constants were dependent on the initial α-tocopherol concentrationn, indicating that the concentration of α-tocopherol and unknown reactant(s) does affect the storage stability of α-tocopherol. The storage parameters of water activity, storage container oxygen content, and storage temperature affected the rate of α-tocopherol loss indicating that these parameters must be controlled to maximize α-tocopherol storage stability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.1981.tb15354.x
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  • 4
    Electronic Resource
    Electronic Resource
    IMPROVED CHROMATOGRAPHIC SEPARATION AND FLUOROMETRIC DETERMINATION OF VITAMIN B6 COMPOUNDS IN FOODS (1977)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 42 (1977), 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: Several fluorometric procedures have been previously developed for the determination of vitamin B6 compounds in foods. These have mainly been based on the separation of pyridoxal (PAL), pyridoxine (PIN), and pyridoxamine (PAM) by column chromatography on Dowex AG 50W-X8, chemical conversion of PIN and PAM to PAL, and formation of the 4-pyridoxic acid lactone fluorophore by reaction with KCN. These procedures were limited by a cumbersome chromatographic procedure utilizing boiling potassium acetate buffers, and interfering compounds in the PAL fraction often precluded accurate measurement. In this study, Maillard browning pigments resulting from the autoclave extraction procedure were shown to interfere by reacting with KCN to form highly fluorescent products. To alleviate the interference problem, an alternative ion exchange chromatographic method was developed which eliminated the KCN-reactive browning pigments from the PAL fraction. After the ion exchange clean up steps, PAL was determined directly by reaction with KCN, whereas PIN and PAM were fist converted to PAL by reaction with MnO2 and sodium glyoxylate, respectively. The effectiveness of the procedure was demonstrated on casein in the presence or absence of glucose, and on selected food samples.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.1977.tb12670.x
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  • 5
    Electronic Resource
    Electronic Resource
    KINETICS AND COMPUTER SIMULATION OF ASCORBIC ACID STABILITY OF TOMATO JUICE AS FUNCTIONS OF TEMPERATURE, pH AND METAL CATALYST (1977)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 42 (1977), 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: The rates of ascorbic acid destruction in tomato juice were determined as functions of storage temperature, pH and copper concentration. Ascorbic acid destruction under anaerobic conditions was confirmed to be a first-order reaction with respect to ascorbic acid concentration. The effect of storage temperature on the rate of ascorbic acid destruction was accounted for by the Arrhenius equation. The activation energy of anaerobic destruction of ascorbic acid was 3.3 kcal/mol at pH 4.06, and was shown to change with changes in pH. The rate of ascorbic acid destruction was influenced by pH, reaching a maximum near the pKa of ascorbic acid. The rate of copper-catalysed destruction of ascorbic acid increased as copper concentration in tomato juice increased, and was affected by pH. A mathematical model, which described the rate of ascorbic acid destruction as functions of storage temperature, pH and copper, was developed based on the experimentally derived equations. A computer simulation program was developed using the mathematical model to predict ascorbic acid stability in tomato juice. The computer-aided predictions of ascorbic acid stability in tomato juice was in good agreement with the results obtained from the shelf-life tests.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.1977.tb12567.x
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  • 6
    Electronic Resource
    Electronic Resource
    KINETICS OF QUALITY DEGRADATION: ASCORBIC ACID OXIDATION IN INFANT FORMULA DURING STORAGE (1976)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 41 (1976), 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: The use of mathematical computer-aided simulations of liquid food quality degradation during storage requires the prior knowledge of kinetics of the reaction rates. In this paper a procedure to obtain this type of information is discussed. The objectives of this study were (1) to determine the rates of ascorbic acid oxidation and oxygen uptake in infant formula and (2) to determine the influence of light intensity on rates of ascorbic acid oxidation and oxygen uptake during storage. The quality index studied in this research was reduced ascorbic acid. Infant formula was selected as the model system. The overall reaction of ascorbic acid degradation and oxygen uptake was assumed and confirmed to be a second-order reaction under limited dissolved oxygen presence in the liquid. The second-order rate constants were calculated for ascorbic acid degradation and dissolved oxygen uptake in infant formula samples exposed to light in 1-cm deep exposure cells. These storage experiments were conducted at five light intensities (dark, 1071 lux, 2142 lux, 3213 lux and 4284 lux) and three initial dissolved oxygen concentrations (1.0 ppm, 4.86 ppm and 8.71 ppm). The results indicated that in samples exposed to light, an increase in initial dissolved oxygen content increased the second-order rate constants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.1976.tb00606.x
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  • 7
    Electronic Resource
    Electronic Resource
    KINETIC ANALYSIS OF LIGHT-INDUCED RIBOFLAVIN LOSS IN WHOLE MILK (1975)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 40 (1975), 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
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.1975.tb03761.x
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  • 8
    Electronic Resource
    Electronic Resource
    Fate of Chlorine During Flour Chlorination (1984)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 49 (1984), 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: Unbleached flour (pH 5.8) was treated with 36Cl2 (g) in a closed-system flour chlorinator to pH levels of 5.25, 4.41, and 4.01. Of the total active Cl2 generated (12.38, 20.71 and 28.17 mg, respectively), 98.6–99.6% was shown to react with the flour. Only 0.35–1.37% was recovered in NaOH traps. Extraction of the treated flour with chloroform showed that 27.0–33.7% of the total 36Cl was incorporated into flour lipids, of which 31.2–39.1% of the radioactivity went to nonpolar lipids and 60.9–68.8% to polar lipids. The water-insoluble and water-soluble fractions of defatted flour contained 17.9–21.4% and 2.1–4.7% of the total 36Cl, respectively. The remaining 36Cl (40.3–49.1%) was present as 36Cl-.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.1984.tb10412.x
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  • 9
    Electronic Resource
    Electronic Resource
    ASSESSMENT OF STORAGE EFFECTS ON VITAMIN B6 STABILITY AND BIOAVAILABILITY IN DEHYDRATED FOOD SYSTEMS (1978)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 43 (1978), 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: The retention of biologically available vitamin B6 during storage was examined using dehydrated food systems fortified with various B6 vitamers. Storage conditions of 37°C and 0.6 water activity (aw) were selected to permit estimation of maximum rates of nonenzymatic browning and vitamin degradation typically encountered in food storage. The stability of the vitamers during storage was evaluated by periodic assay with a high performance liquid chromatographic (HPLC) method. Losses of pyridoxine (PN), pyridoxamine (PM), pyridoxal (PL), and pyridoxal phosphate (PLP) could be described by fist order kinetics. When stored in small volume metal containers, the first order rate constants were 0.015–0.020 day−1 for PL, PM and PLP, and 0.0049 day−1 for PN degradation in food systems. Storage in metal cans which provided a large headspace volume resulted in significantly lower rates of browning and degradation of the B6 vitamers. The only significant degradation mechanism identified was the binding of PLP to proteins to form e-pyridoxyllysine. Correlation of rat bioassay results with microbiological and HPLC assay data indicated that the B6 vitamers remaining after storage for 128 days at 37°C retained full vitamin activity. Determination of the model system vitamin B6 content by the semiautomated fluorometric procedure yielded consistently high results, as found in previous research. These studies indicate that HLPC and microbiological assay results accurately reflect the content of biologically available vitamin B6 in dehydrated food systems after storage at 37°C and 0.6 aw for 128 days. They also demonstrate the potential for application of the HPLC assay to the determination of vitamin B6 in foods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.1978.tb07418.x
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  • 10
    Electronic Resource
    Electronic Resource
    QUANTITATIVE ANALYSIS OF VITAMIN A IN CEREAL PRODUCTS BY HIGH SPEED LIQUID CHROMATOGRAPHY (1977)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 42 (1977), 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: A high speed liquid chromatographic method is described for the determination of vitamin A. Retinol is separated isocratically at ambient temperature via high pressure liquid adsorption chromatography on silica from the nonsaponifiable fraction of the sample. Quantitative determination is accomplished by monitoring the ultraviolet absorbance of retinol at 313 nm. Recovery of vitamin A as retinol in cereal products was 94.3%× 2.01. The primary advantages of this procedure are the use of an isocratic solvent system for the separation of retinol and the elimination of carotenoid interference and toxic chromophore-producing reagents associated with the Cur-Price, trifluoro- and trichloroacetic acid methods. The method offers improved precision for the determination of vitamin A, increases the number of vitamin A assays that can be performed per day, and shows applicability to other food products.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.1977.tb14502.x
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