ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 2005-2009
  • 1975-1979  (8)
  • 1978  (8)
Collection
Keywords
Publisher
Years
  • 2005-2009
  • 1975-1979  (8)
Year
  • 1
    Electronic Resource
    Electronic Resource
    DEMETHYLATION OF PECTIN USING ACID AND AMMONIA (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 kinetics of deesterification of high-ester citrus pectin, using acid, ammonia, or a treatment with acid followed by ammonia in isopropanol was studied with respect to the changes in methyl ester groups, molecular weight, and the formation of acid amide groups. It was found that: (1) Higher concentrations of acid or ammonia at low temperature resulted in less depolymerization for a certain decrease in ester groups; (2) The conversion of methoxyl groups to acid amide groups approached unity as temperature was lowered and ammonia concentration increased. A linear relationship between the increase in amide content and the decrease in esterification was found; (3) In treatments using hydrochloric acid followed by ammonia, a long acid treatment and a short ammonia treatment resulted in a maximum retention of apparent molecular weight. However, this treatment gave a smaller number of acid amide groups in the final product. Depending on the selection of ammonia concentration and temperature, a wide range of acid amide levels was possible. It was also possible to predict the conditions needed for deesterification to give certain apparent molecular weights and ratios of amide levels to ester levels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.1978.tb09739.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    FORMULATION AND CHARACTERISTICS OF LOW-ESTER GELS FROM SUNFLOWER PECTIN (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: Sunflower pectins extracted from a 1:1 mixture of heads and stalks contained 98.5% galacturonic acid of molecular weight 122,200 with ester and acetyl contents of 29.4 and 1.4%, respectively. Gel firmness and strength were evaluated over the ranges of pH 3.0–4.7,15–30 mg Ca++/g pectin, 0.75–1.25% pectin and 10–50% sucrose in the gel formulation. Conditions of pH 4.3, 22.5 mg Ca++/g pectin, 1% pectin and 30% sucrose were optimal for gel firmness and strength. The sunflower pectin gel was particularly sensitive to pH and calcium concentration which had marked influences on pectin solubility, pregelation, brittleness and granularity. A high proportion of free carboxyl groups (69.1%), and possibly nonrandom distribution of demethoxylated groups on the pectin molecules, appeared responsible for the high sensitivity of sunflower pectins to ionic conditions in the gel formulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.1978.tb02408.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    CHEMICAL AND GELATION CHARACTERISTICS OF AMMONIA-DEMETHYLATED SUNFLOWER PECTINS (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: Sunflower head and stalk pectins were demethylated by ammonia-ethanol treatments over a range of concentrations, duration and temperature conditions. The de-esterification treatments decreased the methoxyl and acetyl contents of the pectins and their molecular weights. The associated increases in proportions of acid amide and free carboxyl groups on the polygalacturonic acid molecules were greater in the modified pectins extracted from a head:stalk mixture (1:1 ratio) than in the modified head pectin samples. For all modified pectins there was a general increase in firmness and strength of the prepared gels as the percent esterification decreased from 32 to 14% in these samples. The modified head pectins were superior to those from the head-stalk mixture in pectin solubility, absence of pregelation, and gel smoothness, elasticity, uniformity and stability. The improved gel characteristics of the demethylated pectins were attributed to the increase in acid amide groups and greater randomization of free carboxyl groups in the pectin molecules. The optimum pH of 4.3 for gel formation in the unmodified and most demethylated samples was higher than that of a commercial low-ester pectin, suggesting a particular application in high pH dessert gels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.1978.tb02514.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    EFFECT OF CHEMICAL COMPOSITION ON COMPRESSIVE MECHANICAL PROPERTIES OF LOW ESTER PECTIN GELS (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: Low-ester pectin gels were prepared by acid and a combination of acid and ammonium hydroxide demethylation. The chemical compositional data such as percent esterification, acid amide, free carboxyl, galacturonic acid and apparent molecular weight of the gels were determined. The maximum stress, modulus of elasticity and relaxation time prior to fracture of the low ester pectin gels were evaluated using a universal testing machine. Significant correlations were obtained between (a) relaxation time during fracture propagation and percent esterification; (b) maximum stress and molecular weight; and (c) maximum stress and percent acid amide groups. It was also found that percent acid amide groups in the pectin contributed to the strength of the gels over and above the effect of decreasing percent free carboxyl groups.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.1978.tb02357.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Langkettenverzweigung von Polyvinylacetat und Polyvinylalkohol. 5. Mitt. Bestimmung der Langkettenverzweigung im Polyvinylalkohol (1978)
    Springer
    Colloid & polymer science 256 (1978), S. 202-202 
    Details
    ISSN: 1435-1536
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01679410
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    facet.materialart.
    Unknown
    Langkettenverzweigung von Polyvinylacetat und Polyvinylalkohol. 5. Mitt. Bestimmung der Langkettenverzweigung im Polyvinylalkohol (1978)
    Springer
    Details
    Publication Date: 1978-02-01
    Print ISSN: 0372-820X
    Electronic ISSN: 1435-1536
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by Springer
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 7
    facet.materialart.
    Unknown
    Land use survey and mapping and water resources investigation in Korea (1978)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The author has identified the following significant results. Land use imagery is applicable to land use classification for small scale land use mapping less than 1:250,000. Land use mapping by satellite is more efficient and more cost-effective than land use mapping from conventional medium altitude aerial photographs. Six categories of level 1 land use classification are recognizable from MSS imagery. A hydrogeomorphological study of the Han River basin indicates that band 7 is useful for recognizing the soil and the weathering part of bed rock. The morphological change of the main river is accurately recognized and the drainage system in the area observed is easily classified because of the more or less simple rock type. Although the direct hydrological characteristics are not obtained from the MSS imagery, the indirect information such as the permeability of the soil and the vegetation cover, is helpful in interpreting the hydrological aspects.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: E79-10003 , NASA-CR-157898
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 8
    facet.materialart.
    Unknown
    Interface reaction and characterization in B/Al composites (1978)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: Interfacial reactions, strength degradation, and fracture morphology have been characterized in B/Al(1100) and B/Al(6061) composite systems at a volume fraction of 0.55. Reaction was promoted by isothermal exposure at 350 C or 500 C for times up to 860,000 s. Tetragonal AlB12 was identified as the reaction product in the 6061 matrix and hexagonal AlB2 in the 1100 matrix. Interface development is analyzed based on a moving boundary model modified by the addition of ternary elements. While strength decreases in both systems, the time dependence of elevated-temperature exposure is different in the two matrix materials. In the 45 deg fiber orientation, failure occurs primarily by matrix shear, whereas in the 90 deg fiber orientation, fracture morphology is characterized by a mixture of fiber splitting, ductile matrix fracture, and failure at fiber-matrix interfaces.
    Keywords: COMPOSITE MATERIALS
    Type: ICCM/2; Second International Conference on Composite Materials; Apr 16, 1978 - Apr 20, 1978; Toronto; Canada
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...