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Wang T, Li Y, De Witte F, Rebry F, Li H, Vermeir P, Dewettinck K, Van der Meeren P. Influence of calcium concentration on the re-assembly of sodium caseinate into casein micelles and on their renneting behavior. Food Res Int 2024; 180:113991. [PMID: 38395543 DOI: 10.1016/j.foodres.2024.113991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2023] [Revised: 12/30/2023] [Accepted: 01/05/2024] [Indexed: 02/25/2024]
Abstract
Inducing the spontaneous aggregation from casein molecules (i.e. αs1, αs2, β, and κ-casein) into re-assembled casein micelles (RCMs) through the addition of salts as an alternative to native casein micelles, has garnered increasing attention in recent years. In this investigation, re-assembled casein micelles were generated by adding varying amounts of calcium, phosphate, and citrate ions to a sodium caseinate dispersion. The formed micelles were further characterized in terms of particle size, optical density, and partitioning of calcium ions and caseins. Besides, their small-angle X-ray scattering (SAXS) profiles and renneting properties were evaluated. The observations revealed that the particle size and optical density of RCMs increased with the continuous addition of salts, while the micellar yield improved and could exceed 85 %. Moreover, the quantity of individual casein molecules that contributed to the creation of micelles was in concordance with their level of phosphorylation (i.e. αs2-casein > αs1-casein > β-casein > κ-casein). Mineral analysis results and SAXS scattering profiles confirmed that the added calcium ions acted as cross-linkers and participated in the construction of calcium phosphate nanoclusters. The renneting ability of RCMs was primarily dependent upon the colloidal calcium content per gram of micellar casein.
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Affiliation(s)
- Teng Wang
- Particle and Interfacial Technology Group (PaInT), Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Gent, Belgium.
| | - Yadong Li
- Particle and Interfacial Technology Group (PaInT), Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Gent, Belgium
| | - Fien De Witte
- Food Structure and Function Research Group, Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Ferre Rebry
- Particle and Interfacial Technology Group (PaInT), Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Gent, Belgium
| | - Hao Li
- Particle and Interfacial Technology Group (PaInT), Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Gent, Belgium
| | - Pieter Vermeir
- Laboratory for Chemical Analysis (LCA), Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Koen Dewettinck
- Food Structure and Function Research Group, Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Paul Van der Meeren
- Particle and Interfacial Technology Group (PaInT), Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Gent, Belgium
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2
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Ahmadi E, Markoska T, Huppertz T, Vasiljevic T. Structural Properties of Casein Micelles with Adjusted Micellar Calcium Phosphate Content. Foods 2024; 13:322. [PMID: 38275688 PMCID: PMC10815582 DOI: 10.3390/foods13020322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 01/18/2024] [Accepted: 01/18/2024] [Indexed: 01/27/2024] Open
Abstract
Micellar calcium phosphate (MCP) content of skim milk was modified by pH adjustment followed by dialysis. Turbidity, casein micelle size and partitioning of Ca and caseins between the colloidal and soluble phases of milk were determined. Protein structure was characterised by Fourier transform infrared (FTIR) spectroscopy and proton nuclear magnetic resonance (1H NMR), whereas organic and inorganic phosphorus were studied by phosphorus-31 nuclear magnetic resonance (31P NMR). The sample with the lowest MCP content (MCP7) exhibited the smallest particle size and turbidity, measuring 83 ± 8 nm and 0.08 ± 0.01 cm-1, respectively. Concentrations of soluble caseins increased with decreasing MCP levels. At ~60% MCP removal, FTIR analysis indicated a critical stage of structural rearrangement and 31P NMR analysis showed an increase in signal intensity for Ca-free Ser-P, which further increased as MCP concentration was further reduced. In conclusion, this study highlighted the importance of MCP in maintaining micellar structure and its impact on the integrity of casein micelle.
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Affiliation(s)
- Elaheh Ahmadi
- Advanced Food Systems Research Unit, Institute for Sustainable Industries and Liveable Cities, College of Sport, Health and Engineering, Victoria University, Melbourne, VIC 3001, Australia; (E.A.); (T.M.); (T.H.)
| | - Tatijana Markoska
- Advanced Food Systems Research Unit, Institute for Sustainable Industries and Liveable Cities, College of Sport, Health and Engineering, Victoria University, Melbourne, VIC 3001, Australia; (E.A.); (T.M.); (T.H.)
| | - Thom Huppertz
- Advanced Food Systems Research Unit, Institute for Sustainable Industries and Liveable Cities, College of Sport, Health and Engineering, Victoria University, Melbourne, VIC 3001, Australia; (E.A.); (T.M.); (T.H.)
- FrieslandCampina, 3818 LE Amersfoort, The Netherlands
- Food Quality and Design Group, Wageningen University and Research, 6708 WG Wageningen, The Netherlands
| | - Todor Vasiljevic
- Advanced Food Systems Research Unit, Institute for Sustainable Industries and Liveable Cities, College of Sport, Health and Engineering, Victoria University, Melbourne, VIC 3001, Australia; (E.A.); (T.M.); (T.H.)
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3
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Gebhardt R, Darvishsefat N. Regenerated Fibers from Rennet-Treated Casein Micelles during Acidification. Gels 2023; 9:538. [PMID: 37504417 PMCID: PMC10378896 DOI: 10.3390/gels9070538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 06/25/2023] [Accepted: 06/28/2023] [Indexed: 07/29/2023] Open
Abstract
Micellar casein fibers of defined size and internal structure can be produced by the extrusion of cold-renneted casein micelles into a warm, calcium-rich coagulation bath. Calcium phosphate contacts within the casein matrix are important for fiber stability and production but become less important under acidic pH conditions. We demonstrate this with swelling experiments in media with pH < 2, which we adjust with citric acid of different molarities. In contrast to the simple swelling of dried casein fibers in water, a two-phase process takes place in citric acid similar to swelling in 1 N HCl. However, instead of a second deswelling step, we observe in citric acid that the fiber swells further. The observation is explained by a pH-dependent transition from a rennet casein gel to an acidified rennet gel. This can be simulated with a kinetic model that couples two second-order rate equations via a time-varying ratio. The final swelling values decrease with increasing proton concentration via a scaling relation, which is also confirmed by swelling in other acids (HCl or acetic acid) in this pH range. We attribute this to a decrease in the molecular weights of the aggregated casein structures within the strands of the gel network.
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Affiliation(s)
- Ronald Gebhardt
- Chair of Soft Matter Process Engineering (AVT.SMP), RWTH Aachen University, 52062 Aachen, Germany
| | - Novin Darvishsefat
- Chair of Soft Matter Process Engineering (AVT.SMP), RWTH Aachen University, 52062 Aachen, Germany
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4
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Gebhardt R, Pütz T, Schulte J. Nearly Reversible Expansion and Shrinkage of Casein Microparticles Triggered by Extreme pH Changes. MICROMACHINES 2023; 14:678. [PMID: 36985085 PMCID: PMC10058559 DOI: 10.3390/mi14030678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 03/10/2023] [Accepted: 03/14/2023] [Indexed: 06/18/2023]
Abstract
Solvent flows in the fL/s range across the total surface of a casein microparticle cause its expansion and shrinkage. Microparticles prepared from the milk protein casein have a porous and flexible inner structure with water-filled channels and cavities. Solvent uptake occurs in two phases and results in disintegration if de-swelling is not triggered by acidification. So far, nothing is known about the reversibility of the swelling/de-swelling steps. We performed pH jump experiments between pH 11 and pH 1 on a single micro-particle and analyzed the swelling-induced size changes with system dynamics modeling. Both the swelling steps and the subsequent de-swelling process proceed reversibly and at an unchanged rate over a sequence of at least three pH exchange cycles. We observed that the duration of the first swelling step increased during the sequence, while the second step became shorter. Both of the time intervals are negatively correlated, while a statistical evaluation of only one swelling cycle for an ensemble of microparticles with different stabilities did not reveal any significant correlation between the two parameters. Our results indicate that the pH-induced swelling/shrinkage of casein microparticles is, to a large extent, reversible and only slightly influenced by the acid-induced decomposition of colloidal calcium phosphate.
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5
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Structural, Binding and Functional Properties of Milk Protein-Polyphenol Systems: A Review. Molecules 2023; 28:molecules28052288. [PMID: 36903537 PMCID: PMC10005448 DOI: 10.3390/molecules28052288] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 02/05/2023] [Accepted: 02/20/2023] [Indexed: 03/06/2023] Open
Abstract
Polyphenols (PP) are linked to health benefits (e.g., prevention of cancer, cardiovascular disease and obesity), which are mainly attributed to their antioxidant activity. During digestion, PP are oxidised to a significant degree reducing their bio-functionality. In recent years, the potential of various milk protein systems, including β-casein micelles, β-lactoglobulin aggregates, blood serum albumin aggregates, native casein micelles and re-assembled casein micelles, to bind and protect PP have been investigated. These studies have yet to be systematically reviewed. The functional properties of the milk protein-PP systems depend on the type and concentration of both PP and protein, as well as the structure of the resultant complexes, with environmental and processing factors also having an influence. Milk protein systems protect PP from degradation during digestion, resulting in a higher bioaccessibility and bioavailability, which improve the functional properties of PP upon consumption. This review compares different milk protein systems in terms of physicochemical properties, PP binding performance and ability to enhance the bio-functional properties of PP. The goal is to provide a comprehensive overview on the structural, binding, and functional properties of milk protein-polyphenol systems. It is concluded that milk protein complexes function effectively as delivery systems for PP, protecting PP from oxidation during digestion.
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6
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Runthala A, Mbye M, Ayyash M, Xu Y, Kamal-Eldin A. Caseins: Versatility of Their Micellar Organization in Relation to the Functional and Nutritional Properties of Milk. Molecules 2023; 28:molecules28052023. [PMID: 36903269 PMCID: PMC10004547 DOI: 10.3390/molecules28052023] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 02/10/2023] [Accepted: 02/11/2023] [Indexed: 02/24/2023] Open
Abstract
The milk of mammals is a complex fluid mixture of various proteins, minerals, lipids, and other micronutrients that play a critical role in providing nutrition and immunity to newborns. Casein proteins together with calcium phosphate form large colloidal particles, called casein micelles. Caseins and their micelles have received great scientific interest, but their versatility and role in the functional and nutritional properties of milk from different animal species are not fully understood. Caseins belong to a class of proteins that exhibit open and flexible conformations. Here, we discuss the key features that maintain the structures of the protein sequences in four selected animal species: cow, camel, human, and African elephant. The primary sequences of these proteins and their posttranslational modifications (phosphorylation and glycosylation) that determine their secondary structures have distinctively evolved in these different animal species, leading to differences in their structural, functional, and nutritional properties. The variability in the structures of milk caseins influence the properties of their dairy products, such as cheese and yogurt, as well as their digestibility and allergic properties. Such differences are beneficial to the development of different functionally improved casein molecules with variable biological and industrial utilities.
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Affiliation(s)
- Ashish Runthala
- Department of Biotechnology, Koneru Lakshmaiah Education Foundation, Vijayawada 522302, India
- Correspondence: (A.R.); (A.K.-E.); Tel.: +971-5-0138-9248 (A.K.-E.)
| | - Mustapha Mbye
- Department of Food Science, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates
| | - Mutamed Ayyash
- Department of Food Science, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates
| | - Yajun Xu
- Department of Nutrition and Food Hygiene, School of Public Health, Peking University, Beijing 100871, China
| | - Afaf Kamal-Eldin
- Department of Food Science, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates
- Zayed Bin Sultan Center for Health Sciences, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates
- Correspondence: (A.R.); (A.K.-E.); Tel.: +971-5-0138-9248 (A.K.-E.)
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7
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Characterization of the white dots defect (“PIPS”) in “Doce de leite”. Eur Food Res Technol 2022. [DOI: 10.1007/s00217-022-04149-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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8
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Mathew R, Stevensson B, Pujari-Palmer M, Wood CS, Chivers PRA, Spicer CD, Autefage H, Stevens MM, Engqvist H, Edén M. Nuclear Magnetic Resonance and Metadynamics Simulations Reveal the Atomistic Binding of l-Serine and O-Phospho-l-Serine at Disordered Calcium Phosphate Surfaces of Biocements. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2022; 34:8815-8830. [PMID: 36248225 PMCID: PMC9558313 DOI: 10.1021/acs.chemmater.2c02112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 09/09/2022] [Indexed: 06/16/2023]
Abstract
Interactions between biomolecules and structurally disordered calcium phosphate (CaP) surfaces are crucial for the regulation of bone mineralization by noncollagenous proteins, the organization of complexes of casein and amorphous calcium phosphate (ACP) in milk, as well as for structure-function relationships of hybrid organic/inorganic interfaces in biomaterials. By a combination of advanced solid-state NMR experiments and metadynamics simulations, we examine the detailed binding of O-phospho-l-serine (Pser) and l-serine (Ser) with ACP in bone-adhesive CaP cements, whose capacity of gluing fractured bone together stems from the close integration of the organic molecules with ACP over a subnanometer scale. The proximity of each carboxy, aliphatic, and amino group of Pser/Ser to the Ca2+ and phosphate species of ACP observed from the metadynamics-derived models agreed well with results from heteronuclear solid-state NMR experiments that are sensitive to the 13C-31P and 15N-31P distances. The inorganic/organic contacts in Pser-doped cements are also contrasted with experimental and modeled data on the Pser binding at nanocrystalline HA particles grown from a Pser-bearing aqueous solution. The molecular adsorption is driven mainly by electrostatic interactions between the negatively charged carboxy/phosphate groups and Ca2+ cations of ACP, along with H bonds to either protonated or nonprotonated inorganic phosphate groups. The Pser and Ser molecules anchor at their phosphate/amino and carboxy/amino moieties, respectively, leading to an extended molecular conformation across the surface, as opposed to an "upright standing" molecule that would result from the binding of one sole functional group.
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Affiliation(s)
- Renny Mathew
- Department
of Materials and Environmental Chemistry, Stockholm University, Stockholm SE-106 91, Sweden
| | - Baltzar Stevensson
- Department
of Materials and Environmental Chemistry, Stockholm University, Stockholm SE-106 91, Sweden
| | - Michael Pujari-Palmer
- Applied
Material Science, Department of Engineering, Uppsala University, Uppsala SE-751 21, Sweden
| | - Christopher S. Wood
- Department
of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm SE-171 77, Sweden
| | - Phillip R. A. Chivers
- Department
of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm SE-171 77, Sweden
| | - Christopher D. Spicer
- Department
of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm SE-171 77, Sweden
- Department
of Chemistry, University of York, Heslington, York YO10 5DD, U.K.
| | - Hélène Autefage
- Department
of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm SE-171 77, Sweden
| | - Molly M. Stevens
- Department
of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm SE-171 77, Sweden
- Department
of Materials, Department of Bioengineering, and Institute of Biomedical
Engineering, Imperial College London, London SW7 2AZ, U.K.
| | - Håkan Engqvist
- Applied
Material Science, Department of Engineering, Uppsala University, Uppsala SE-751 21, Sweden
| | - Mattias Edén
- Department
of Materials and Environmental Chemistry, Stockholm University, Stockholm SE-106 91, Sweden
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9
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Blinov AV, Siddiqui SA, Blinova AA, Khramtsov AG, Oboturova NP, Nagdalian АА, Simonov AN, Ibrahim SA. Analysis of the dispersed composition of milk using photon correlation spectroscopy. J Food Compost Anal 2022. [DOI: 10.1016/j.jfca.2022.104414] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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10
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Malik S, De I, Singh M, Galanakis CM, Alamri AS, Yadav JK. Isolation and characterisation of milk-derived amyloid-like protein aggregates (MAPA) from cottage cheese. Food Chem 2022; 373:131486. [PMID: 34800818 DOI: 10.1016/j.foodchem.2021.131486] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Revised: 10/22/2021] [Accepted: 10/25/2021] [Indexed: 11/15/2022]
Abstract
Cottage cheese, extensively consumed worldwide, contains coagulated milk protein (casein), produced through boiling and acidification of milk. Casein forms amyloid or amyloid-like structures at high temperatures and low pH. Due to the similarities in the preparation of casein amyloids and cottage cheese, we hypothesized the presence of amyloid or amyloid-like protein aggregates in cottage cheese. To examine this hypothesis, cottage cheese was prepared from cow (Bos indicus) milk and isolated amyloids through a water extraction method. The isolated protein aggregates displayed typical characteristics of amyloids, such as a bathochromic shift in the wavelength of maximum absorption (λmax) of Congo red (CR), high thioflavin T (ThT) binding, increased surface hydrophobicity, and high β-sheet structure. However, they did not show antibacterial activity and toxic properties against erythrocytes. Our study revealed that the heat-treatment and subsequent acidification during cottage cheese preparation lead to the formation of non-toxic amyloid-like aggregates.
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Affiliation(s)
- Shweta Malik
- Department of Biotechnology, School of Life Sciences, Central University of Rajasthan, NH-8 Bandarsindri, Kishangarh, Ajmer 305817, Rajasthan, India
| | - Indranil De
- Institute of Nano Science and Technology, Mohali 160062, Punjab, India
| | - Manish Singh
- Institute of Nano Science and Technology, Mohali 160062, Punjab, India
| | - Charis M Galanakis
- Research & Innovation Department, Galanakis Laboratories, Chania, Greece; Food Waste Recovery Group, ISEKI Food Association, Vienna, Austria; Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, Taif, Saudi Arabia
| | - Abdulhakeem S Alamri
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, Taif, Saudi Arabia; Centre of Biomedical Sciences Research (CBSR), Deanship of Scientific Research, Taif University, Saudi Arabia
| | - Jay Kant Yadav
- Department of Biotechnology, School of Life Sciences, Central University of Rajasthan, NH-8 Bandarsindri, Kishangarh, Ajmer 305817, Rajasthan, India.
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11
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Mathew R, Stevensson B, Edén M. Refined Structures of O-Phospho-l-serine and Its Calcium Salt by New Multinuclear Solid-State NMR Crystallography Methods. J Phys Chem B 2021; 125:10985-11004. [PMID: 34553936 PMCID: PMC8503883 DOI: 10.1021/acs.jpcb.1c05587] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Indexed: 12/17/2022]
Abstract
O-phospho-l-serine (Pser) and its Ca salt, Ca[O-phospho-l-serine]·H2O (CaPser), play important roles for bone mineralization and were recently also proposed to account for the markedly improved bone-adhesive properties of Pser-doped calcium phosphate-based cements for biomedical implants. However, the hitherto few proposed structural models of Pser and CaPser were obtained by X-ray diffraction, thereby leaving the proton positions poorly defined. Herein, we refine the Pser and CaPser structures by density functional theory (DFT) calculations and contrast them with direct interatomic-distance constraints from two-dimensional (2D) nuclear magnetic resonance (NMR) correlation experimentation at fast magic-angle spinning (MAS), encompassing double-quantum-single-quantum (2Q-1Q) 1H NMR along with heteronuclear 13C{1H} and 31P{1H} correlation NMR experiments. The Pser and CaPser structures before and after refinements by DFT were validated against sets of NMR-derived effective 1H-1H, 1H-31P, and 1H-13C distances, which confirmed the improved accuracy of the refined structures. Each distance set was derived from one sole 2D NMR experiment applied to a powder without isotopic enrichment. The distances were extracted without invoking numerical spin-dynamics simulations or approximate phenomenological models. We highlight the advantages and limitations of the new distance-extraction procedure. Isotropic 1H, 13C, and 31P chemical shifts obtained by DFT calculations using the gauge including projector augmented wave (GIPAW) method agreed very well with the experimental results. We discuss the isotropic and anisotropic 13C and 31P chemical-shift parameters in relation to the previous literature, where most data on CaPser are reported herein for the first time.
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Affiliation(s)
- Renny Mathew
- Department of Materials and Environmental
Chemistry, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Baltzar Stevensson
- Department of Materials and Environmental
Chemistry, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Mattias Edén
- Department of Materials and Environmental
Chemistry, Stockholm University, SE-106 91 Stockholm, Sweden
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12
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13
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Bauland J, Famelart M, Bouhallab S, Jeantet R, Roustel S, Faiveley M, Croguennec T. Addition of calcium and magnesium chlorides as simple means of varying bound and precipitated minerals in casein micelle: Effect on enzymatic coagulation. J Dairy Sci 2020; 103:9923-9935. [DOI: 10.3168/jds.2020-18749] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 06/26/2020] [Indexed: 11/19/2022]
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14
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Markoska T, Vasiljevic T, Huppertz T. Unravelling Conformational Aspects of Milk Protein Structure-Contributions from Nuclear Magnetic Resonance Studies. Foods 2020; 9:E1128. [PMID: 32824355 PMCID: PMC7466366 DOI: 10.3390/foods9081128] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 08/11/2020] [Accepted: 08/13/2020] [Indexed: 11/30/2022] Open
Abstract
Changes in the molecular structure and association of milk proteins lead to many desirable (under controlled conditions) or undesirable characteristics of dairy products. Several methods have been used to study the structure of milk proteins and changes therein in different environments. Whey proteins are an excellent model for secondary structure studies using circular dichroism (CD), Fourier-transform infrared spectroscopy (FTIR) and tertiary structure studies using X-ray crystallography and nuclear magnetic resonance (NMR). However, caseins, the most abundant protein class in milk, are far more difficult to characterize. The tertiary structure of caseins cannot be observed by X-ray crystallography due to the inability to crystallize caseins. However, NMR is an appropriate approach for structural elucidation. Thus far, NMR was applied on specific peptides of individual caseins of the molecules including phosphoserine centers and colloidal calcium phosphate. The literature focuses on these parts of the molecule due to its importance in building the sub-unit particles involving individual caseins and calcium phosphate nanoclusters. This review focuses on present structural studies of milk proteins using NMR and their importance in dairy processing.
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Affiliation(s)
- Tatijana Markoska
- Advanced Food Systems Research Unit, Institute for Sustainable Industries and Liveable Cities, College of Health and Biomedicine, Victoria University, Melbourne VIC 8001, Australia; (T.M.); (T.V.)
| | - Todor Vasiljevic
- Advanced Food Systems Research Unit, Institute for Sustainable Industries and Liveable Cities, College of Health and Biomedicine, Victoria University, Melbourne VIC 8001, Australia; (T.M.); (T.V.)
| | - Thom Huppertz
- Advanced Food Systems Research Unit, Institute for Sustainable Industries and Liveable Cities, College of Health and Biomedicine, Victoria University, Melbourne VIC 8001, Australia; (T.M.); (T.V.)
- FrieslandCampina, 3818 LE Amersfoort, The Netherlands
- Food Quality and Design Group, Wageningen University and Research, 6808 WG Wageningen, The Netherlands
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15
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Effect of freezing temperatures and time on mineral balance, particle size, rennet and acid coagulation of casein concentrates produced by microfiltration. Int Dairy J 2020. [DOI: 10.1016/j.idairyj.2019.104563] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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16
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Bystrom JL, Pujari-Palmer M. Phosphoserine Functionalized Cements Preserve Metastable Phases, and Reprecipitate Octacalcium Phosphate, Hydroxyapatite, Dicalcium Phosphate, and Amorphous Calcium Phosphate, during Degradation, In Vitro. J Funct Biomater 2019; 10:E54. [PMID: 31783637 PMCID: PMC6963472 DOI: 10.3390/jfb10040054] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 11/19/2019] [Accepted: 11/20/2019] [Indexed: 01/15/2023] Open
Abstract
Phosphoserine modified cements (PMC) exhibit unique properties, including strong adhesion to tissues and biomaterials. While TTCP-PMCs remodel into bone in vivo, little is known regarding the bioactivity and physiochemical changes that occur during resorption. In the present study, changes in the mechanical strength and composition were evaluated for 28 days, for three formulations of αTCP based PMCs. PMCs were significantly stronger than unmodified cement (38-49 MPa vs. 10 MPa). Inclusion of wollastonite in PMCs appeared to accelerate the conversion to hydroxyapatite, coincident with slight decrease in strength. In non-wollastonite PMCs the initial compressive strength did not change after 28 days in PBS (p > 0.99). Dissolution/degradation of PMC was evaluated in acidic (pH 2.7, pH 4.0), and supersaturated fluids (simulated body fluid (SBF)). PMCs exhibited comparable mass loss (<15%) after 14 days, regardless of pH and ionic concentration. Electron microscopy, infrared spectroscopy, and X-ray analysis revealed that significant amounts of brushite, octacalcium phosphate, and hydroxyapatite reprecipitated, following dissolution in acidic conditions (pH 2.7), while amorphous calcium phosphate formed in SBF. In conclusion, PMC surfaces remodel into metastable precursors to hydroxyapatite, in both acidic and neutral environments. By tuning the composition of PMCs, durable strength in fluids, and rapid transformation can be obtained.
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Affiliation(s)
| | - Michael Pujari-Palmer
- Applied Material Science, Department of Engineering, Uppsala University, 75121 Uppsala, Sweden;
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Silva NN, Casanova F, Pinto MDS, Carvalho AFD, Gaucheron F. Micelas de caseína: dos monômeros à estrutura supramolecular. BRAZILIAN JOURNAL OF FOOD TECHNOLOGY 2019. [DOI: 10.1590/1981-6723.18518] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Resumo A importância primária das micelas de caseína reside no fato de que os processos empregados na transformação do leite em quaisquer de seus derivados dependem, direta ou indiretamente, de sua estabilidade ou de sua desestabilização controlada. Assim, o objetivo do presente trabalho é apresentar uma revisão atualizada sobre a organização estrutural das micelas de caseína. Em termos físico-químicos, as micelas de caseína podem ser definidas como agregados supramoleculares esféricos e porosos, altamente hidratados, carregados negativamente, com diâmetro médio de 200 nm, e que apresentam aproximadamente 104 cadeias polipeptídicas. Além de água, as micelas são constituídas por quatro tipos de caseínas, chamadas de αS1, αS2, β, e κ-caseínas, que estão unidas por meio de interações hidrofóbicas e eletrostáticas, e pela presença de minerais, sobretudo sais de fosfato de cálcio, os quais são os principais responsáveis pela manutenção da estrutura micelar. A estabilidade das micelas de caseína é atribuída à presença de uma camada externa difusa, formada basicamente por κ-caseína. Apesar de as propriedades coloidais das micelas de caseína serem conhecidas, ainda não há consenso sobre como as moléculas de caseína estão estruturadas em seu interior. Portanto, os principais modelos que descrevem a organização interna das micelas de caseína são apresentados na parte final do artigo.
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