Comparison of Hydration Behavior of Bovine and Caprine Caseins As Determined by Oxygen-17 Nuclear Magnetic Resonance: Effects of Salt

Mora-Gutierrez, Adela; Farrell, Harold M.; Kumosinski, Thomas F.

doi:10.1021/jf00058a004

Cited by 19 publications

(28 citation statements)

References 23 publications

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“…It is known that α ‐caseins are the major proteins in cow milk, whereas β ‐casein is the major protein in goat or sheep milk. The percentage of α ‐casein is higher in sheep's than in goat's milk but significantly lower than in cow's milk . Moreover, bands relevant to γ ‐caseins were detected at very low molecular weights with a lower percentage in sheep milk.…”

Section: Resultsmentioning

confidence: 88%

Detection of sheep and goat milk adulterations by direct MALDI–TOF MS analysis of milk tryptic digests

et al. 2012

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In dairy field, one of the most common frauds is the adulteration of higher value types of milk (sheep's and goat's) with milk of lower value (cow's milk). This illegal practice has an economic advantage for milk producers and poses a threat for consumers' health because of the presence of hidden allergens as, for example, cow milk proteins, in particular, α(s1)-casein and β-lactoglobulin. The urgent need of sensitive techniques to detect this kind of fraud brought to the development of chromatographic, immunoenzymatic, electrophoretic and mass spectrometric assays. In the current work, we present a fast, reproducible and sensitive method based on the direct matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) MS analysis of milk tryptic digests for the detection of milk adulteration by evaluating specie-specific markers in the peptide profiles. Several pure raw and commercial milk samples and binary mixtures containing cows' and goats', cows' and sheep's and goats' and sheep's milk (concentrations of each milk varied from 0% to 100%) were prepared, and tryptic digests were analyzed by MALDI-TOF MS. The use of the new MALDI matrix α-cyano-4-chlorocinnamic acid allowed to detect cow and goat milk peptide markers up to 5% level of adulteration. Finally, from preliminary data, it seems that the strategy could be successfully applied also to detect similar adulterations in cheese samples.

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Section: Resultsmentioning

confidence: 88%

Detection of sheep and goat milk adulterations by direct MALDI–TOF MS analysis of milk tryptic digests

et al. 2012

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“…The major results are reported in Table I. Enrichment of milk in micellar casein decreased water transfer at the end of drying and during rehydration. Insolubility [15] was related to decrease in the water transfer needed for rehydration and not to thermal denaturation, and the decrease in water transfer was related to the micelle structure. The destructuration of micelle induced by addition of phosphate or citrate solution to MC increased water transfer during drying and during rehydration.…”

Section: Discussionmentioning

confidence: 99%

“…In spite of this significant improvement in the reconstitution rate and slight solubilization of the micellar calcium, the relaxation rate (R 2 s) of the reconstituted solution in the presence of NaCl was not significantly different from the pure MC relaxation rate. It has been hypothesized that NaCl should exert little influence on micelle structure [15] and that the signifiant decrease in the RP value is more probably related to the hygroscopic strength of NaCl.…”

Section: Nmr Spectroscopymentioning

confidence: 99%

Water transfer during rehydration of micellar casein powders

Schuck¹,

Méjean²,

Dolivet³

et al. 2007

Lait

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Rehydration is an essential quality attribute of a dairy powder, as most powders are dissolved before use. However, there can be problems associated with the different stages of the rehydration process: i.e. wettability, sinkability, dispersibility and solubility. Many sensors and analytical methods such as the insolubility index, NMR spectroscopy, turbidity, viscosity and particle size distribution can be used to study water transfer in dairy protein concentrates during rehydration. Micellar casein (MC) powder, obtained by tangential membrane microfiltration of milk followed by spray-drying, is an interesting dairy powder due to its high protein content, and it is a valuable model of milk micelles. However, enrichment of milk in micellar casein decreases water transfer during rehydration of MC powder. The slow water transfer during MC powder rehydration is timeconsuming. Some studies have shown that insolubility is related to a decrease in the water transfer during rehydration and not to thermal denaturation. Other studies have also shown that the decrease in water transfer might be related to the micellar structure. In the present study, the destructuration of micelle induced by addition of phosphate or citrate solution to MC increased water transfer during rehydration. Water transfer in the dairy protein concentrate during rehydration was found to be related to the aqueous environment, the nature of the mineral salts, the structure of the dairy proteins, the size of the powder particle and the rehydration conditions. micellar casein / powder / rehydration / wettability / dispersibility / solubility* Corresponding author (通讯作者): pierre.schuck@rennes.inra.fr Article published by EDP Sciences and available at http://www.lelait-journal.org or http://dx.doi.org/10.1051/lait:2007016 426 P. Schuck et al. Résumé -Transfert d'eau au cours de la réhydratation de poudres de caséine micellaire.La réhydratation est un facteur déterminant essentiel de la qualité d'une poudre laitière puisque la plupart des poudres doivent être dissoutes avant utilisation. Des problèmes peuvent apparaître au cours des différentes étapes du procédé de réhydratation, i.e. : aptitude au mouillage/mouillabilité, aptitude au coulage/coulabilité, dispersibilité et solubilité. De nombreux moyens de détection et méthodes d'analyse, comme l'indice d'insolubilité, la spectroscopie RMN, la turbidité, la viscosité, la distribution des tailles de particules, peuvent être utilisés pour étudier le transfert d'eau dans les concentrés de protéines laitières au cours de la réhydratation. La poudre de caséine micellaire (CM), obtenue par microfiltration du lait suivie de séchage par atomisation, est une poudre laitière intéressante du fait de sa teneur élevée en protéine, et un modèle valable des micelles du lait. Cependant, l'enrichissement du lait en CM diminue le transfert d'eau au cours de la réhydratation de la poudre de CM. La lenteur du transfert d'eau augmente le temps de réhydratation de la poudre de CM. Quelques études ont montré que l'insolubilité é...

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“…I), the relaxation rate R 2s of the reconstituted solution in the presence of NaCl was not significantly different from the pure NPCS relaxation rate (Tab. II): it is hypothesized that NaCl would exert little influence on micelle structure [7] and that the big decrease in the RP value is more probably related to the hygroscopic strength of NaCl.…”

Section: Effect Of the Addition Of Saltsmentioning

confidence: 99%

Article

Davenel¹,

Schuck

Mariette³

et al. 2002

Lait

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-The ability to quickly solubilize powders in aqueous medium without forming insoluble material is of primary importance for the quality of many food powders. The NMR method developed gives a complete picture of the reconstitution process of milk powders in water. It allows the quantification of the water absorption by powder particles, their reconstitution rate and the detection of the presence of insoluble materials. Furthermore, the NMR transverse relaxation rate of the reconstituted product is proved to be an excellent indicator of the structural state of milk proteins. It is shown that the poor reconstitutability of native cow phosphocasein micelles concentrated by tangential microfiltration and powdered by spray-drying can be significantly improved by addition of whey proteins, suitable polydextroses or NaCl before spray-drying powder, without significantly affecting their micellar structure. On the other hand, the decrease of the relaxation rate showed an important modification of the casein structure when a citrate solution or, to a lesser extent, when a phosphate solution was added to the retentate. The addition of CaCl 2 strongly disturbed the micellar organization and led to the formation of insoluble structures during spray-drying.Milk powder / NMR relaxation / rehydration / solubilization / micellar casein Résumé -La relaxométrie RMN comme outil non invasif de caractérisation des poudres laitiè-res. La capacité à se solubiliser rapidement en milieu aqueux est de première importance pour la qualité de nombreuses poudres alimentaires. La méthode RMN développée donne une description complète du processus de reconstitution des poudres dans l'eau. Elle permet de quantifier le phéno-mène d'absorption d'eau par les particules, la vitesse de reconstitution et de révéler la présence de matériaux insolubles. D'autre part, la vitesse de relaxation RMN tranversale du produit reconstitué s'avère être un excellent indicateur de l'état structural des protéines laitières. Il est montré que la médiocre reconstituabilité des micelles de caséines bovines natives concentrées par microfiltration tangentielle puis séchées par atomisation peut être significativement améliorée par l'addition préa-lable au séchage de protéines laitières solubles, de certaines maltodextrines ou de NaCl avant atomisation sans affecter significativement la structure des micelles. D'autre part, la décroissance des vitesses de relaxation de l'eau en interaction avec les macromolécules traduit d'importants changements de la structure des protéines quand une solution citrate ou, dans une moindre mesure, quand une solution phosphate est ajoutée. L'addition de CaCl 2 perturbe fortement l'organisation micellaire et conduit à la formation de matériaux insolubles en cours de séchage.Poudre laitière / relaxation RMN / réhydratation / solubilisation / caséine micellaire

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Comparison of Hydration Behavior of Bovine and Caprine Caseins As Determined by Oxygen-17 Nuclear Magnetic Resonance: Effects of Salt

Cited by 19 publications

References 23 publications

Detection of sheep and goat milk adulterations by direct MALDI–TOF MS analysis of milk tryptic digests

Detection of sheep and goat milk adulterations by direct MALDI–TOF MS analysis of milk tryptic digests

Water transfer during rehydration of micellar casein powders

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