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  • 1
    Electronic Resource
    Electronic Resource
    Stabilization of the Prussian blue color in the determination of polyphenols (1992)
    s.l. : American Chemical Society
    Journal of agricultural and food chemistry 40 (1992), S. 801-805 
    Details
    ISSN: 1520-5118
    Source: ACS Legacy Archives
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jf00017a018
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  • 2
    Electronic Resource
    Electronic Resource
    EFFECT OF PLANT GROWTH REGULATORS ON PLANT NUTRIENTS (1980)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 45 (1980), 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: Tomato, pea, and New Zealand spinach plants were treated with gibberellic acid, Cycocel, and Phosfon. The tomatoes, green peas, and spinach leaves were analyzed for proteins, soluble carbohydrates, starch, ascorbic acid, niacin, β-carotene, and titratable acidity. Cycocel and Phosfon increased proteins in all products, starch in green peas and tomatoes, and ascorbic acid in spinach and tomatoes. Cycocel increased β-carotene in spinach and tomatoes. Phosfon increased β-carotene in tomatoes and soluble carbohydrates in green peas and tomatoes. Gibberellic acid increased proteins, soluble carbohydrates, and ascorbic acid in all the products and starch and β-carotene in the tomato. Gibberellic acid caused extended growth, production of smaller tomatoes and beans, and more disease-susceptible plants. Cycocel- and Phosfon-treated plants were sturdier, greener, water and insect resistant, and produced larger tomatoes or beans or thicker spinach leaves.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.1980.tb04086.x
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  • 3
    Electronic Resource
    Electronic Resource
    Quantitative Aspects of the Interaction of Carrageenan and Other Hydrocolloids with Polyvalent Cobalt Complexes (1966)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 31 (1966), 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: Carrageenan, other sulfated polysaccharides, and carboxylic acid polysaccharides react with hexol nitrate, hexamine cobaltic chloride, and tris-(ethylenediamine) -cobalt III chloride in aqueous solution to give precipitates which exhibit differential solubilities in solutions of simple salts. The turbidity (optical density) produced when the hydrocolloids are mixed with these cobalt complexes is proportional to the amount of hydrocolloid present. Salts inhibit the reaction, and, generally, the order of inhibition is: monovalent cations 〈 divalent cations 〈 trivalent cations.The temperature and pH of the reaction medium greatly influence the final turbidity developed. Generally, the complexes formed through the reaction of the sulfated polysaccharides and the cobalt complexes are less readily dissolved by solutions of simple salts than those formed by the carboxylic polysaccharides and the cobalt complexes. Neutral polysaccharides are not precipitated by the cobalt complexes, hence three component systems containing a sulfated, a carboxylic, and a neutral polysaccharide can be resolved and the individual components determined quantitatively. Good resolution was obtained with a mixture such as carrageenan (sulfated) plus algin (carboxylic) plus locust bean gum (neutral).Quantitative assay of those polysaccharides which form precipitates (turbidity) with the complexes can be done either by measuring the turbidity developed or by determining spectrophotometrically the amount of cobalt complex cation bound. These colored complexes have sharp absorption maxima: hexol nitrate, max = 490 mμ; hexaminecobalt chloride, max = 475 mμ; and tris-(ethylenediamine)-cobalt III chloride, max = 470 mμ.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.1966.tb00507.x
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  • 4
    Electronic Resource
    Electronic Resource
    Quantitative Determination of Piperine. I. The Komarowsky Reaction (1965)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 30 (1965), 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 highly stable reagent consisting of para-dimethylaminobenzaldehyde (I) or para-hydroxybenzaldehyde (II) or other cylic aldehydes, plus thioureau in concentrated sulfuric acid, has been developed for use in determining piperine. The slightly yellow reagent, if stored under refrigeration in a brown bottle, maintains a constant chromogenic capacity for 4–6 weeks. Piperine when heated with this reagent for 15 min at 100°C develops a red color (I max. 490 mp) or purple color (II max. 570 mμ) whose intensity is proportional to the amount of piperine present. Water inhibits color development, but a small amount of methyl alcohol is necessary. Ethyl alcohol cannot be used, since it develops color with the reagent. Critical factors for reproducible, quantitative assay are the concentration of acid and thiourea in the reagent and the time and temperature of heating the reaction mixture. For I, the most sensitive of the aldehydes used, good precision, with a standard deviation of it ± 3470, was attained. Between the levels of 0.01 and 0.06μM of piperine per ml of reagent, there is a linear relation which may be described by the least-squares equation.X = 0.088 Y + 0.00175 where X = concentration (μM) of piperine per ml of reagent Y = absorbance at 490 μM Percent piperine in sample = X (0.28533) (dilution factor)′ 100 Sample weight (mg)
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.1965.tb01818.x
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  • 5
    Electronic Resource
    Electronic Resource
    Quantitative Determination of Carrageenan in Milk and Milk Products Using Papain and Cetyl Pyridinium Chloride (1968)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 33 (1968), 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: SUMMARY– Proteins in milk, chocolate milk, evaporated milk, and ice cream containing added carrageenan were digested with papain at 70°C in the presence of 1.0 M NaCl. The digest was adjusted to pH 8.0 to 8.5 with NaOH. Celite was added and the mixture filtered over glass wool. Carrageenan in the filtrate was precipitated with cetyl pyridinium chloride (C.P.C.) in the presence of 0.5 to 1.0 M KCl and Celite. The carrageenan-C.P. precipitate was washed with 0.1% C.P.C.-0.05 M KCI until the filtrate was negative to the Benedict's test. Then, it was dissolved in 30% H2SO4 and the carbohydrate content determined by the phenol-H2SO4 method.At concentrations of 0.01 to 0.2% carrageenan, average recoveries of 92 to 102% were obtained from milk. For chocolate milk, evaporated milk and ice cream, and at a level of 0.1% carrageenan, recoveries of 90, 94 and 96%, respectively, were obtained. Optimum conditions for the isolation of the carrageenan cetyl pyridinium complex were established.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.1968.tb03636.x
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  • 6
    Electronic Resource
    Electronic Resource
    Quantitative Aspects of the Interaction of Carrageenan with Cationic Substances (1962)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 27 (1962), 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: Using the interaction of carrageenan (Seakem type 5) with cetylpyridinium chloride as the type example, investigation was made of optimum conditions for the precipitation of carrageenan and its fractions by quaternary ammonium detergents. Found to be very critical factors for quantitative precipitation were the temperature and pH of the reaction medium. Comparatively, the amount of detergent cation bound by a particular sulfated hydrocolloid is indicative of its degree of sulfation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.1962.tb00066.x
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  • 7
    Electronic Resource
    Electronic Resource
    Precipitation of Food Gums by Thiazine, Oxazine, Azine and Other Cationic Dyes: Specificity of the Methylene Blue Carrageenan Reaction (1961)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 26 (1961), 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 dyes of the thiazine, azine, azo and other classes were mixed with carrageenan, furcellaran, fucoidan and other hydrocolloids and the nature of the precipitates formed was carefully observed. The results obtained indicate that the antigen-antibody-like specificity ascribed to the methylene blue-carrageenan reaction is much less rigid than previously thought.Dyes bearing the thiazine, phenazine, azine, oxazine or azo core structure will give the typical methylene blue-carrageenan stringy precipitate when mixed with the hydrocolloids mentioned above. The sulfated polygalactose moiety is an essential for the formation of such a precipitate. Salts, at concentrations above certain threshold levels, inhibit formation of the stringy precipitate and, at low pH levels of the medium, the strings are considerably shortened. It is postulated that formation of the stringy precipitate results from the tendency of the linear macromolecules of carrageenan to agglomerate into fibers on precipitation from solutions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.1961.tb00374.x
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  • 8
    Electronic Resource
    Electronic Resource
    DETERMINATION OF CARBOXYMETHYLCELLULOSE IN FOOD PRODUCTS (1971)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 36 (1971), 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: SUMMARY –A method was developed to determine sodium carboxymethylcellulose (CMC) in food products containing three or more hydrocolloids after prior removal of interfering substances. Papain was used to digest the proteins; calcium chloride was added to precipitate algin and pectic acid and sulfated hydrocolloids were then precipitated by cetylpyridinium chloride (CPC) in the presence of 0.5M NaCl. Celite 535 or Hyflo Super Cel was added, the mixture filtered over Reeve angel No. 202 paper and the residue washed with 0.01% CPC-0.01M NaCl. The filtrate and washings were collected and diluted with distilled water to attain a final concentration of 0.2M NaCl at which concentration the CMC was precipitated selectively by CPC. The mixture was filtered over a Celite 535 or Hyflo Super Cel column and the residue washed with 0.5M Na2SO4 and then with 0.01% CPC-0.01M NaCl until the washings were negative to the phenol-H2SO4 reagent. Finally, the residue on the column was washed with hot 30% H2SO4 and the hydrolyzed CMC in the eluate determined by the 2,7-naphthalenediol test. Based on the amount added to mixtures, recoveries of 75–86% were obtained from milk and other highly complex and proteinaceous products, with a standard deviation of ± 0.58 mg, when 10 mg of CMC were added. The determination is critically dependent upon the degree of substitution (DS) of the CMC. As a consequence, the method cannot be applied with absolute certainty to unknown samples.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.1971.tb03344.x
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  • 9
    Electronic Resource
    Electronic Resource
    SPECIFICITY OF THE FERRIC-H2SO4 REAGENT FOR ALGINATES (1970)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 35 (1970), 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: SUMMARY— Alginate in foods was isolated from papain digests of the samples as the insoluble calcium salt. dispersed by sodium hexametaphosphate and a 1- to 5-ml aliquot of the dispersion 50–250 μg of sodium alginate) dried at 100°C. Heating of the anhydrous sample in the presence of the ferric-H2SO4 reagent for 12 min at 60°C produced a pink color with maximum absorption at 490–515 mμ and maximum density after aging for 90 min at 29±1°C. Under these conditions, proteins, amino acids (except tryptophane), other carbohydrates, vitamins. food additives and incipients did not interfere. The presence of water in the medium rendered the reaction nonspecific and increasing the temperature above 60°C or heating for longer periods at lower temperatures resulted in color formation by other polyuronides, especially pectin and pectic acid. Recoveries of alginate from several products were good: Milk, 94–98%; ice cream, 93.5–98%; pasteurized process cheese spread. 92.6-95%; chocolate milk, 92.4-95%; dietetic foods, 90-97.2%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.1970.tb00967.x
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  • 10
    Electronic Resource
    Electronic Resource
    Reaction of Sugar Alcohols with the Anthrone Reagent (1963)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 28 (1963), 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: Under appropriate conditions of acid concentration, heating time and temperature of heating, the sugar alcohols react with the anthrone reagent in a quantitative manner. Suitable conditions for reproducible quantitative results are: 0.15% anthrone in concentrated sulfuric acid and a heating time of 60 min at 99°C (in a boiling-water bath). Color measurement should be made 30 minutes after cooling the reaction tubes in an ice water bath, since the intensity of the colors increased with time. Of the various sugar alcohols tested, the order of reactivity is: Glycerol 〉 sorbitol 〉 mannitol 〉 dulcitol 〉 erythri-tol 〉 arabitol 〉 ribitol 〉 xylitol. Absorption maxima occurred at 720 mμ, for mannitol, sorbitol, and dulcitol, and at 740 mμ for erythritol. Glycerol and the other sugar alcohols exhibited no sharp absorption maxima.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.1963.tb00224.x
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