Investigation of β-Lactoglobulin Gelation in Water/Ethanol Solutions

Dufour, Éric; Robert, Paul; Renard, Denis; Llamas, Geneviève

doi:10.1016/s0958-6946(98)00024-7

Cited by 31 publications

(34 citation statements)

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“…The first feature was the appearance of an absorption at about 1 620 cm -1 during ripening which may be connected to modifications of the protein network. As previously reported [9,15], the increase of the absorbance at about 1 620 cm -1 could be related to the changes in the interactions of the protein network during ripening time. On the other hand, this band has been correlated with differences of water activity in samples (Mazerolles, unpublished data).…”

Section: Canonical Correlation Analysis Of Infrared and Chemical Datasupporting

confidence: 73%

“…As stated previously [11,17,27], this part of infrared spectra is used to investigate the secondary structures of several proteins. While the absorption band around 1 615 cm -1 has been assigned by Abott [1] to the side chains of protein, several other authors [9,15] have observed that variations around 1 620 cm -1 occurred during protein aggre-gation. The absorption band at 1 535 cm -1 is generally linked to Amide II vibration, as reported by Bellamy [2].…”

Section: Effects Of Ripening On the Infrared Spectrum In The Amide I mentioning

confidence: 98%

“…The development of the attenuated total reflectance (ATR) device allows the sampling problems encountered when collecting spectra from opaque and viscous samples to be overcome. This simple and reproducible method made it possible to investigate the aggregation and gelation kinetics of β-lactoglobulin at a molecular level [15].…”

Section: Introductionmentioning

confidence: 99%

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Infrared and fluorescence spectroscopy for monitoring protein structure and interaction changes during cheese ripening

Mazerolles

Devaux²,

Duboz

et al. 2001

Lait

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Sixteen experimental semi-hard cheeses, varying in moisture (42.1 to 49.8%), protein (20.2 to 25.9%) and fat (23.7 to 31.1%) content, were manufactured and ripened under controlled conditions. Fluorescence (tryptophan) and mid-infrared (Amide I and II regions) spectra were collected at 1, 21, 51 and 81 days of ripening in order to test the ability of spectroscopy to highlight the molecular changes that occur during this process. The mid-infrared and fluorescence spectral data from the experimental cheeses were analysed firstly by principal component analysis. Secondly, the correlations between the chemical domain and the spectral domains were studied by canonical correlation analysis methods. These analyses showed that each spectroscopic technique provided relevant information related to the cheese protein structure, which was used to discriminate each ripening stage. In addition, some spectral characteristics of ripened cheeses, linked to the initial chemical composition and the initial protein network structure, were detected at the early stage of ripening. Finally, a canonical correlation analysis between the two sets of spectroscopic data was performed and allowed to clearly discriminate each stage of ripening and each cheese at the 4 ripening stages. A molecular interpretation of these results involving the modifications of proteins, minerals and water interactions during ripening was attempted. This result demonstrated the interest of coupling two complementary spectroscopic techniques. Such coupling allowed the description of global characteristics of the investigated samples, which can be used for their characterisation.

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Section: Canonical Correlation Analysis Of Infrared and Chemical Datasupporting

confidence: 73%

Section: Effects Of Ripening On the Infrared Spectrum In The Amide I mentioning

confidence: 98%

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Infrared and fluorescence spectroscopy for monitoring protein structure and interaction changes during cheese ripening

Mazerolles

Devaux²,

Duboz

et al. 2001

Lait

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“…The β‐LG is known to form gels in solution under various conditions in which the protein is likely to be at least partially unfolded, for example, at high temperatures (Langton and Hermansson 1992; Bauer et al 1998; Relkin et al 1998), under high hydrostatic pressure (Zasypkin et al 1996; Dumay et al 1998), or in the presence of chemical denaturants (Katsuta et al 1997; Dufour et al 1998; Renard et al 1999). Because the gels formed under certain conditions have different characters, there has been increasing interest in the utilization of β‐LG gels to improve the quality of food products (Smithers et al 1996).…”

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confidence: 99%

A kinetic study of β‐lactoglobulin amyloid fibril formation promoted by urea

2002

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The formation of fibrillar aggregates by ␤-lactoglobulin in the presence of urea has been monitored by using thioflavin T fluorescence and transmission electron microscopy (TEM). Large quantities of aggregated protein were formed by incubating ␤-lactoglobulin in 3-5 M urea at 37°C and pH 7.0 for 10-30 days. The TEM images of the aggregates in 3-5 M urea show the presence of fibrils with diameters of 8-10 nm, and increases in thioflavin T fluorescence are indicative of the formation of amyloid structures. The kinetics of spontaneous fibrillogenesis detected by thioflavin T fluorescence show sigmoidal behavior involving a clear lag phase. Moreover, addition of preformed fibrils into protein solutions containing urea shows that fibril formation can be accelerated by seeding processes that remove the lag phase. Both of these findings are indicative of nucleation-dependent fibril formation. The urea concentration where fibril formation is most rapid, both for seeded and unseeded solutions, is ∼ 5.0 M, close to the concentration of urea corresponding to the midpoint of unfolding (5.3 M). This result indicates that efficient fibril formation involves a balance between the requirement of a significant population of unfolded or partially unfolded molecules and the need to avoid conditions that strongly destabilize intermolecular interactions.

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“…Biophysical studies on model membranes such as liposomes have also been quite successful in characterizing the organization and dynamics of a lipid matrix. The development of Fourier transform infrared (FTIR) spectroscopy in recent years affords the possibility of obtaining unique information about protein structure [2, 15,34,35,37], lipid organisation [9,12] and lipid-protein interaction [27,36] without introducing perturbing probe molecules. The infrared bands appearing in the 3 000-2 800 crrr ' region are particularly useful because they are sensitive to the conformation and the packing of the phospholipid acyl chains [9,27,39].…”

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confidence: 99%

Whey proteins modify the phase transition of milk fat globule phospholipids

Dufour¹,

Subirade

Loupil³

et al. 1999

Lait

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-The phospholipids extracted from milk fat globule membranes were composed of three major classes, phosphatidylethanolamines (37.2 %), phosphatidylcholines (30.0 %), sphingomyelin (28.2 %), and two minor classes, phosphatidylinositols (2.0 %) and phosphatidylserines (2.6 %). The thermogram showed that the extracted phospholipids presented a single wide-phase transition centered at 18.3 oc. The effects of temperature on the phase behaviour of milk phospholipids in the presence of~-Iactoglobulin and a-Iactalbumin have been studied at pH 4.0 and 7.0 (with or without calcium) using Fourier transform infrared spectroscopy. Principal component analysis carried out on the spectra in the 3 000-2 800 cm-i region showed that the binding of the whey proteins to the phospholipids modified the Iipid phase transition in different ways, depending on the in-solution protein. © Inra/Elsevier, Paris milk 1 phospholipid 1 protein 1 interaction 1 phase behaviour 1 infrared Résumé -L'arrangement des phospholipides extraits des globules gras du lait est modifié par la présence de la~-lactoglobuline et de l'a-lactalbumine. Les phospholipides extraits de la membrane du globule gras comprennent des phosphatidylethanolamines (37,2 %), des phosphatidylcholines (30,0 %), des sphingomyélines (28,2 %), des phosphatidylsérines (2,6 %) et des phosphatidylinositols (2,0 %). Le thermogramme des phospholipides du lait présente un pic large avec une seule transition de phase à 18,3 oc. L'effet de la température sur l'arrangement des phospholipides extraits des globules gras du lait en présence de la~-Iactoglobuline et de l'a-lactalbumine a été étudié par spectroscopie moyen infrarouge à pH 4,0 et 7,0 (en présence ou en absence de calcium). L'analyse en composantes principales réalisée sur les spectres correspondant à la région 3000-2800 cm-i montre qu'aux deux pH étudiés, l'arrangement des phospholipides est modifié suite à leurs interactions avec les protéines du lactosérum. © Inra/Elsevier, Paris lait 1 phospholipide 1 protéine 1 interaction 1 transition de phase 1 infrarouge * Correspondence and reprints at present address: ENIT A -Clermont-Ferrand, Marmilhat, 63370 Lempdes, France. dufourrs'gentiane.enitac.fr ifier protein of the lactose synthase complex in the mammary cell. The secondary structure of this protein yields 45 % of a-helix and 5 % of p-sheet [1]. Ptitsyn [31] showed that oe-lactalbumin has a 'molten globule state' conformation at low pH. This conformational state may facilitate the insertion of proteins in membranes [18,19,24].Studies of lipid-protein interaction in reconstituted model systems have been an active topic for a numbers of years [9,17,25,27,36,39].These studies provide basic information about the molecular organization of biological membranes. Biophysical studies on model membranes such as liposomes have also been quite successful in characterizing the organization and dynamics of a lipid matrix. The development of Fourier transform infrared (FTIR) spectroscopy in recent years affords the possibility of ob...

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Investigation of β-Lactoglobulin Gelation in Water/Ethanol Solutions

Cited by 31 publications

References 0 publications

Infrared and fluorescence spectroscopy for monitoring protein structure and interaction changes during cheese ripening

Infrared and fluorescence spectroscopy for monitoring protein structure and interaction changes during cheese ripening

A kinetic study of β‐lactoglobulin amyloid fibril formation promoted by urea

Whey proteins modify the phase transition of milk fat globule phospholipids

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