Library

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
  • 1
    Electronic Resource
    Electronic Resource
    Rheological examination of material with cellular structure II. Creep and oscillation measurements of apple material with cellular structure (1997)
    Springer
    Zeitschrift für Lebensmittel-Untersuchung und -Forschung 205 (1997), S. 193-203 
    Details
    ISSN: 1431-4630
    Keywords: Key wordsMaterial with cellular structure ; Creep measurements ; Oscillation measurements ; Rheological parameters ; Material properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract  Properties of rehydrated materials with cellular structure can be investigated by making creep and oscillation measurements. Such rehydrated material and alcohol-insoluble substances can be classified rheologically as concentrated suspensions with viscoelastic properties. As well as its concentration, the material properties of the disperse phase are important determinants of the rheological properties of disperse systems. In our creep measurement experiments under defined conditions dominant reversible elastic parts are obtained at high concentrations ≥90%. Frequency sweep measurements within the linear-viscoelastic region at γ = 0.001 leads to the assumption that all rehydrated samples are dispersions. This is due to the fact that storage and loss moduli are almost independent of the measuring frequency. The alcohol-insoluble substance forms the most stable dispersion, followed by the basic material. In contrast, the homogenized material had dominant viscous properties. The results are specific for each material and depend on the frequency and concentration. Data derived from rheological measurements allow a complex characterization of materials with cellular structure through mathematical models (linear relationships).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002170050150
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Preparation of single-cell material from enzymatically disintegrated apple tissue – changes in structure and functional properties (1997)
    Springer
    Zeitschrift für Lebensmittel-Untersuchung und -Forschung 205 (1997), S. 380-387 
    Details
    ISSN: 1431-4630
    Keywords: Key words Single-cell material ; Pectolytic enzyme preparations ; Structure degradation ; Functional properties ; Granny Smith apples
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract  Apple tissue was treated with commercial pectolytic enzyme preparations (one preparation for mash maceration, two preparations for mash fermentation, one preparation for total liquefaction), disintegrated and processed into single-cell material. The dependence of changes in tissue structure as well as the related functional properties of the cell material on the enzyme preparation and the length of treatment were studied. The yield of cell material, the particle size distribution, the galacturonan content, porosity, water-binding capacity as well as scanning electron micrographs were used for the evaluation of the material’s structure and properties. Only the macerase treatment led to a significant yield of cell material that was high both in its quantity of separated cells and its water-binding capacity. Treatment with the other enzyme preparations resulted in a significant loss of quantity and/or quality. The galacturonan content in the cell material was highly correlated with the particle size distribution as well as with its porosity and water-binding capacity. Accordingly, the galacturonan content relates the structural degradation that results from enzymatic activity to the functional properties of the final product.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002170050185
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Wasserbindungskapazität und Makrostruktur von Apfelgewebepartikeln (1993)
    Springer
    European food research and technology 196 (1993), S. 219-223 
    Details
    ISSN: 1438-2385
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Description / Table of Contents: Zusammenfassung Haufwerke aus trockenen Apfelgewebepartikeln mit mittleren Partikelvolumina zwischen 0,3 und 5 mm3 können bis zu 80 g/g Wasser aufnehmen. Der überwiegende Teil dieses Wassers ist in makrocapillaren Haufwerks- und Partikelhohlräumen eingelagert und nur durch sehr geringe Kräfte gebunden. Bereits bei Einwirkung eines Gasdrucks von 2 kPa werden die Partikelhaufwerke stark entwässert. Die Wasserbeladung sinkt auf 20-15 g/g. Die Rehydratation einzelner getrockneter Apfelgewebepartikel ist vom Ausmaß der bei der Zerkleinerung eingetretenen Gewebezerstörung abhängig und kann durch eine der Trocknung vorgelagerte Entwässerung mit Ethanol verbessert werden. Vorentwässerte Partikel mit einem hohen Ethanolgehalt schrumpfen bei der Trocknung im geringeren Ausmaß und besitzen eine hohe Porosität. Solche Partikel binden im rehydratisierten Zustand bis zu 30 g/g Wasser. Nicht mit Ethanol behandelte Partikel binden unter 11 g/g Wasser.
    Notes: Abstract Samples (bulk materials) of dry apple tissue particles in a range of particle volume from 0.3 to 5 mm3 can absorb up to 80 g/g water. Most of this water is included in macrocapillary bulk and particle spaces and is bound by very small forces. An external gas pressure of 2 kPa decreases the water content to 20-15 g/g. The rehydration properties of single apple tissue particles depend on the degree of tissue disintegration and can be improved by a dehydration treatment with ethanol before drying. Such pre-dehydrated particles with a high ethanol concentration in the liquid phase show little shrinkage during the drying process and have a high porosity. They retain up to 30 g/g water after rehydration. The water uptake of non-ethanol-treated particles is less than 11 g/g.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01202735
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Einsatz der Druckhomogenisierung zur Herstellung von zellstrukturiertem Apfelmaterial (1994)
    Springer
    European food research and technology 198 (1994), S. 239-243 
    Details
    ISSN: 1438-2385
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Description / Table of Contents: Zusammenfassung Unter Einsatz eines Druckhomogenisators können ausgehend von Apfelparenchymgewebe zellstrukturierte Materialien (ZM) mit einem Maximum der Korngrößenverteilung im Bereich von 140–200 μm und einem Wasserbindevermögen von 55–70 g/g hergestellt werden. Die Ergebnisse der Untersuchungen werden wesentlich durch die gewählten Parameter des Homogenisierschritts beeinflußt: Zunehmender Druck und steigende Homogenisierzeiten führen einerseits zu einer Vervollständigung der Zerkleinerung und der Extraktion wasserlöslicher Inhaltsstoffe, andererseits jedoch zu sinkendem Wasserbindevermögen der ZM und zu einer Abnahme der Fließgrenze der rehydratisierten Proben. Durch den Schritt des Homogenisierens lassen sich ferner die Farbe und das Aussehen der hergestellten ZM verbessern.
    Notes: Abstract Materials with cellular structure having a maximum of particle size from 140 to 200 μm and a water binding capacity of 55 to 70 g/g can be prepared from apple parenchyma using a pressure homogenizer. The results of the investigations are essentially influenced by the parameters of homogenisation step: Rising pressure and increasing homogenization time on the one hand leads to a higher degree of desintegration and a completer extraction of water soluble substances, but on the other hand the water binding capacity of the materials and the flow limit value of the rehydrated samples are decreased. The homogenization step also improves the colour and the visual impression of the materials with cellular structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01192602
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Herstellung und Charakterisierung von eiweißarmem, zellstrukturiertem Material (1994)
    Springer
    European food research and technology 199 (1994), S. 235-239 
    Details
    ISSN: 1438-2385
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Description / Table of Contents: Zusammenfassung Die molekularen Parameter und die funktionellen Eigenschaften eiweißarmer zellstrukturierter Materialien (ZM) werden sowohl durch die Herstellungsbedingungen als auch durch die Art der verwendeten Rohstoffe bestimmt. Die im Vergleich zu alkoholunlöslicher Substanz veränderten Herstellungsbedingungen führen über einen Extraktionsschritt im alkalischen Milieu und eine vorteilhafte Kombination von Verfahrensschritten zu besonders eiweißarmen und pectinreichen Materialien mit verbesserten funktionellen Eigenschaften, insbesondere bezüglich Wasserbindevermögen und Kationenaustauscherkapazität. Am Beispiel von Apfel-, Möhren und Weißkohl-ZM kann gezeigt werden, daß einerseits Lösungsmittelbedarf und Ausbeute sowie andererseits die molekularen Parameter und die funktionellen Eigenschaften teilweise auch in sehr signifikanter Weise vom eingesetzten Rohmaterial abhängen. So zeichnet sich Apfel-ZM durch einen besonders niedrigen Eiweißgehalt und hohes Wasserbindevermögen, Möhren-ZM mit entesterter Pectinkomponente dagegen durch gute Ausbeute, hohen Pectinanteil und einen beachtlichen Gehalt freier Carboxylgruppen von〉1,5 mmol/g aus.
    Notes: Abstract The molecular parameters and functional properties of low-protein materials with a cellular structure are determined by both the conditions of preparation and the kind of raw material used. Compared to alcohol-insoluble substance, the conditions of preparation were modified. When an alkaline extraction and a favorable combination of processing steps is used, materials with special low protein and high pectin contents result. In addition, such functional properties as water binding capacity and cation exchange capacity of the materials are improved. After having prepared various materials with a cellular structure from apple, carrot, and white cabbage, it was found that the amount of solvent needed and the yield, as well as the molecular parameters and the functional properties were also determined by the kind of raw materials used. For instance, material with a cellular structure from apple is low in protein and high in water binding capacity. Whereas, materials with a cellular structure from carrot, which contains a deesterified pectin component, is characterized by a good yield, a high pectin content, and an excess of 1,5 mmol/g of free carboxyl groups.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01193452
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Rheologische Untersuchungen von zellstrukturierten Materialien (1996)
    Springer
    European food research and technology 203 (1996), S. 351-365 
    Details
    ISSN: 1438-2385
    Keywords: Apple ; Cellular structured material ; Rheology of cellular material ; Casson viskosity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Rehydrated material with cellular structure and alcohol insoluble substance may be regarded as concentrated suspension with viscoelastic properties. The rheological properties of disperse systems are determined on the basis of the material properties of the disperse phase apart from its concentration. The material properties of the disperse phase depend on the macrostructural parameters of the particles including the interactions occuring and the chemical structure of the cell wall. The material properties of the rehydrated material with cellular structure may be detected by means of classical rheological examinations and specifically systemizing their evaluation. The description of material with cellular structure with the aid of CASSON's model and the further investigation of the yield stress τ0 as a function of its concentration and of the effektive viscosity ηeff as a function of its concentration and shear rateγ seem to be established. If comprehensivly applied this method allows to interpret the rheological properties of the material with cellular structure in specific respect. The dominant linear dependence of the influencing variables yield stress, CASSON's viscosity and effectiv viscosity on concentration is especially remarkable.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01231074
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Herstellung und Charakterisierung von eiweißarmem zellstrukturiertem Material (1994)
    Springer
    European food research and technology 199 (1994), S. 43-47 
    Details
    ISSN: 1438-2385
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Description / Table of Contents: Zusammenfassung Zellstrukturierte Materialien (ZM) mit einem niedrigen Eiweiß-, aber hohem Pectingehalt können nach einfachen Verfahren mit geringer Anzahl von Prozeßstufen und niedrigem Lösungsmittelverbrauch aus pflanzlichem Gewebe hergestellt werden. Apfel-ZM mit einem geringen Eiweißgehalt 〈4% und einem hohen Wasserbindevermögen 〉80 g/g sind aus den Preßrückständen von Apfelparenchymgewebe durch Extrahieren bei pH 8,4–9,1 und Temperaturen von 30–40 °C, Blanchieren im wäßrigen Milieu, Entwässern durch Ethanol und schonende thermische Endtrocknung zugänglich. Über die zusätzlichen Schritte der Verseifung und des Waschens mit Säuren werden die Apfel-ZM als aschearme Präparate mit niedrigem Veresterungsgrad der Pectinkomponente erhalten. Derartige ZM zeichnen sich durch einen hohen Gehalt an freien Carboxylgruppen von 〉1 mmol/g aus, weisen jedoch ein reduziertes Wasserbindevermögen auf.
    Notes: Abstract Materials with cellular structure and a low protein content but a high pectin content have been prepared from apple parenchyma by simple procedures with only a few steps using small amounts of solvents. Materials with cellular structure from apple and a protein content less than 4% and a water-binding capacity higher than 80 g/g were obtained from the pressing residues of apple parenchyma by extraction at pH 8,4 to 9,1 and temperatures from 30 to 40° C, blanching in an aqueous environment, dehydration by ethanol and careful final thermal drying. Futhermore, additonal steps of alkaline deesterification and washing with acid were carried out for the preparation of samples with a low degree of esterification of the pectin component and a small content of ash. Such materials have a high content of free carboxyl groups (more than 1 mmol/g), but a reduced water-binding capacity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01192951
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Einfluß von Ethanol auf den Trocknungsverlauf und die Makrostruktur eines Einzel-Zellmaterials aus Apfelparenchym (Sorte Granny Smith) (1996)
    Springer
    European food research and technology 203 (1996), S. 512-516 
    Details
    ISSN: 1438-2385
    Keywords: Single cell material ; Drying behaviour ; Macrostructure ; Functional properties ; Apples
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Ethanol pre-treated apple parenchyma cells are dried in a laboratory vacuum dryer. Various ethanol contents (75 to 95% m/m) and moisture contents (2 to 15 g ethanol-water-mixture per g dry mass) of the cells were adjusted before drying and the influence of these factors on drying behaviour as well as the related structural changes are studied. The initial ethanol content was found to have a significant influence on both, drying behaviour and macrostructure of the dried material. In the case of a low initial value, the ethanol content during drying already drops at moisture contents of about 0.5–1.5 g/g. As a consequence the residual particle moisture consists mainly of water at the end of drying. In contrast to high initial ethanol contents, cells at a low initial ethanol content become strongly deformed on drying. The porosity of the dried material also decreases in the latter case, relatively large and stable aggregates are formed and the water binding capacity of the dried product has diminished on a large scale. The initial moisture content influences the drying behaviour especially on applying low initial ethanol contents. If the initial moisture content is reduced the drop of the ethanol content is shifted towards the end of the drying process. The influence of initial moisture content on macrostructure, however, was found to be small compared with the effect of the initial ethanol content.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01193155
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Herstellung und Charakterisierung von zellstrukturiertem Apfelmaterial mit unterschiedlichem Pectingehalt (1993)
    Springer
    European food research and technology 197 (1993), S. 353-357 
    Details
    ISSN: 1438-2385
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Description / Table of Contents: Zusammenfassung Ausgehend von Apfelparenchymgewebe wurden alkoholunlösliche Substanzen als hellfarbige Materialien mit cellularer Struktur und unterschiedlichem Pectingehalt hergestellt. Die Materialien haben unabhängig vom Pectingehalt vergleichbare funktionelle Eigenschaften und besitzen ein hohes Wasserbindevermögen über 50 g/g. Jedoch wird das Wasserbindevermögen bei den pectinarmen Materialien durch den Schritt der Pectinextraktion herabgesetzt. Die Herstellung des zellstrukturierten Materials mit niedrigem Pectingehalt kann über den Schritt einer einstufigen sauren Pectinextraktion mit der Isolierung von hochverestertem, hochmolekularem Pectin verknüpft werden. Beim Autoklavieren von rehydratisierten zellstrukturierten Materialien werden beträchtliche Mengen an wasserlöslichem, hoch verestertem, niedermolekularem Pectin freigesetzt. Das Autoklavieren und nachfolgende Aufbewahren der Proben bei Raumtemperatur führt zu sinkenden Werten der Helligkeit und der Fließgrenze.
    Notes: Abstract Alcohol-insoluble substances in the form of light (colourless) materials with a cellular structure and two different pectin contents have been prepared from apple parenchyma. Except for the water-binding capacity, the pectin content was found to have only a small effect on the functional properties of the materials. The water-binding capacity of the materials was decreased by a step of pectin extraction. However, in all cases the water-binding capacity was higher than 50 g/g. It was found that the depectinization of the materials with a cellular structure by acid one-step pectin extraction can be combined with the isolation of a highly methoxylated, high-molecular-mass pectin. Considerable amounts of water-soluble, highly methoxylated but low-molecular-mass pectins are released from rehydrated materials with a cellular structure when subjected to autoclave treatment. Both autoclaving and storage at room temperature decrease the lightness and the flow limit value of the rehydrated materials.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01242060
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Charakterisierung der Größenverteilung von Einzel-Zellmaterial mit der Laser-Partikel-Analyse (1995)
    Springer
    European food research and technology 201 (1995), S. 387-389 
    Details
    ISSN: 1438-2385
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Laser particle analysis has been used to measure the size distribution of single cell suspensions obtained from both, apple and carrot tissue. Volume distribution shows the effect of mechanic and enzymatic operations on tissue disintegration. With an approximate size calculation of particle aggregates formed during drying, a better interpretation of distribution functions of dried and rehydrated cells is possible.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01192739
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...