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Investigation of beta-carotene-gelatin composite particles with a multiwavelength UV/vis detector for the analytical ultracentrifuge.

Karabudak E, Wohlleben W, Cölfen H - Eur. Biophys. J. (2009)

Bottom Line: A multiwavelength UV/vis detector for the analytical ultracentrifuge (MWL-AUC) has been developed recently.In addition, our data suggest that pure H- and J-aggregates exist in a particle while their relative concentrations in a mixture determine the color characteristics of the sample.These properties significantly extend the scope of the analytical ultracentrifuge technique and show that complex biopolymer multicomponent mixtures can be resolved into their individual species.

View Article: PubMed Central - PubMed

Affiliation: Colloid Chemistry, Max Planck Institute of Colloids and Interfaces, Research Campus Golm, 14424 Potsdam, Germany.

ABSTRACT
A multiwavelength UV/vis detector for the analytical ultracentrifuge (MWL-AUC) has been developed recently. In this work, beta-carotene-gelatin composite particles are investigated with MWL-AUC. Band centrifugation with a Vinograd cell is used to ensure maximum sample separation. Spectral changes of the system are observed in dependence of the sedimentation coefficient and are attributed to a previously unknown inhomogeneity of the beta-carotene chemical composition with both H- and J-aggregates coexisting in a mixture. In addition, our data suggest that pure H- and J-aggregates exist in a particle while their relative concentrations in a mixture determine the color characteristics of the sample. The unique abilities and properties of MWL-AUC include sedimentation coefficient distributions for all possible wavelengths, full UV/vis spectra of each different species in the mixture and 3D movies of the sedimentation process. These properties significantly extend the scope of the analytical ultracentrifuge technique and show that complex biopolymer multicomponent mixtures can be resolved into their individual species.

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Related in: MedlinePlus

Dashed line UV/vis spectrum of the core-shell β-carotene/gelatin sample with 0.05 g/l concentration; solid line UV/vis spectrum of gelatin at 1 g/l
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Fig1: Dashed line UV/vis spectrum of the core-shell β-carotene/gelatin sample with 0.05 g/l concentration; solid line UV/vis spectrum of gelatin at 1 g/l

Mentions: There are two forms of hydrosol that are explained in Auweter et al. (1999). β-carotenes can precipitate as H-aggregate or J-aggregate; the two morphologies do not interconvert and are regarded to be kinetically stable over years. The H-aggregate is observed in precipitation of dilute solutions (0.3 weight%) whereas the J-aggregate is observed at higher concentration (1.0 weight%). Auweter et al. (1999) calculated a 40 nm hypsochromic shift observed for an H-aggregate and a bathochromic shift in J-aggregates. This results in a significant color change from yellow to red of the product depending on the precipitation conditions and hybrid particle size (Figs. 1, 2). This color change is the basis for the industrial application of the β-carotenes as pigments for food applications.Fig. 1


Investigation of beta-carotene-gelatin composite particles with a multiwavelength UV/vis detector for the analytical ultracentrifuge.

Karabudak E, Wohlleben W, Cölfen H - Eur. Biophys. J. (2009)

Dashed line UV/vis spectrum of the core-shell β-carotene/gelatin sample with 0.05 g/l concentration; solid line UV/vis spectrum of gelatin at 1 g/l
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2812708&req=5

Fig1: Dashed line UV/vis spectrum of the core-shell β-carotene/gelatin sample with 0.05 g/l concentration; solid line UV/vis spectrum of gelatin at 1 g/l
Mentions: There are two forms of hydrosol that are explained in Auweter et al. (1999). β-carotenes can precipitate as H-aggregate or J-aggregate; the two morphologies do not interconvert and are regarded to be kinetically stable over years. The H-aggregate is observed in precipitation of dilute solutions (0.3 weight%) whereas the J-aggregate is observed at higher concentration (1.0 weight%). Auweter et al. (1999) calculated a 40 nm hypsochromic shift observed for an H-aggregate and a bathochromic shift in J-aggregates. This results in a significant color change from yellow to red of the product depending on the precipitation conditions and hybrid particle size (Figs. 1, 2). This color change is the basis for the industrial application of the β-carotenes as pigments for food applications.Fig. 1

Bottom Line: A multiwavelength UV/vis detector for the analytical ultracentrifuge (MWL-AUC) has been developed recently.In addition, our data suggest that pure H- and J-aggregates exist in a particle while their relative concentrations in a mixture determine the color characteristics of the sample.These properties significantly extend the scope of the analytical ultracentrifuge technique and show that complex biopolymer multicomponent mixtures can be resolved into their individual species.

View Article: PubMed Central - PubMed

Affiliation: Colloid Chemistry, Max Planck Institute of Colloids and Interfaces, Research Campus Golm, 14424 Potsdam, Germany.

ABSTRACT
A multiwavelength UV/vis detector for the analytical ultracentrifuge (MWL-AUC) has been developed recently. In this work, beta-carotene-gelatin composite particles are investigated with MWL-AUC. Band centrifugation with a Vinograd cell is used to ensure maximum sample separation. Spectral changes of the system are observed in dependence of the sedimentation coefficient and are attributed to a previously unknown inhomogeneity of the beta-carotene chemical composition with both H- and J-aggregates coexisting in a mixture. In addition, our data suggest that pure H- and J-aggregates exist in a particle while their relative concentrations in a mixture determine the color characteristics of the sample. The unique abilities and properties of MWL-AUC include sedimentation coefficient distributions for all possible wavelengths, full UV/vis spectra of each different species in the mixture and 3D movies of the sedimentation process. These properties significantly extend the scope of the analytical ultracentrifuge technique and show that complex biopolymer multicomponent mixtures can be resolved into their individual species.

Show MeSH
Related in: MedlinePlus