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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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Kondakova EV, Filat’eva AE, Lobanova NA, Nagaev EI, Sarimov RM, Gudkov SV, Vedunova MV. Case report: Applicability of breastfeeding the child of a patient with kidney failure with replacement therapy. Front Med (Lausanne) 2023; 10:1098324. [PMID: 36844211 PMCID: PMC9950765 DOI: 10.3389/fmed.2023.1098324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 01/27/2023] [Indexed: 02/12/2023] Open
Abstract
This case report highlights the benefit or harm of breastfeeding in a patient with Kidney Failure with Replacement Therapy (KFRT) undergoing program hemodialysis. This is a unique clinical case, as pregnancy and successful delivery are rare in this group of females. With a favorable outcome, the possibility of breastfeeding is especially relevant for doctors and the mother. The patient was a 31-year-old female who was diagnosed in 2017 with end-stage renal disease associated with chronic glomerulonephritis. Against the background of hemodialysis, pregnancy, accompanied by polyhydramnios, anemia, and secondary arterial hypertension, occurred in 2021. At 37 weeks, a healthy, full-term baby girl was born, and breastfeeding was started. In this study, we conducted a detailed analysis of toxic substances and immunologically significant proteins using high-tech analysis methods. In addition, we studied different portions of milk before and after hemodialysis at different time intervals. After a wide range of experiments, our study did not reveal an optimal time interval for breastfeeding a baby. Despite the decrease in the level of the major uremic toxins 4 h after the hemodialysis procedure, their level remained high. In addition, the content of nutrients did not reach acceptable limits and the immune status was characterized as pro-inflammatory. In our opinion, breastfeeding is not advisable for this group of patients since the concentration of nutrients is low, and the content of toxic substances exceeds the permissible limits. In this clinical case, the patient decided to stop breastfeeding one month after delivery due to insufficient breast milk and the inability to express it in a certain period of time.
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Affiliation(s)
- Elena V. Kondakova
- Institute of Biology and Biomedicine, Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia,*Correspondence: Elena V. Kondakova,
| | - Anastasia E. Filat’eva
- Institute of Biology and Biomedicine, Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
| | - Nadezhda A. Lobanova
- Institute of Biology and Biomedicine, Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia,Branch FESFARM NN, Nizhny Novgorod, Russia
| | - Egor I. Nagaev
- Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow, Russia
| | - Ruslan M. Sarimov
- Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow, Russia
| | - Sergey V. Gudkov
- Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow, Russia
| | - Maria V. Vedunova
- Institute of Biology and Biomedicine, Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
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Wawer J, Andrukajtis M, Karczewski J, Zielińska-Jurek A, Piątek R. Fibrillar aggregates in powdered milk. J DAIRY RES 2023; 90:1-5. [PMID: 36694366 DOI: 10.1017/s002202992300002x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
This research paper addresses the hypothesis that powdered milk may contain amyloid fibrils. Amyloids are fibrillar aggregates of proteins. Up to this time, research on the presence of amyloids in food products are scarce. To check the hypothesis we performed thioflavin T fluorescence assay, X-ray powder diffraction, atomic force microscopy and fluorescence microscopy imaging. Our preliminary results show that commercially available milks contain fibrils that have features characteristic to amyloids. The obtained results can be interpreted in two opposite ways. The presence of amyloids could be considered as a hazard due to the fact that food products may induce amyloid related diseases. On the other hand, the presence of amyloids in traditionally consumed foodstuffs could serve as proof that fibrils of food proteins do not pose a threat for consumers.
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Affiliation(s)
- Jarosław Wawer
- Department of Physical Chemistry, Faculty of Chemistry, Gdańsk University of Technology, Narutowicza Str. 11/12, 80-233 Gdańsk, Poland
| | - Martyna Andrukajtis
- Department of Physical Chemistry, Faculty of Chemistry, Gdańsk University of Technology, Narutowicza Str. 11/12, 80-233 Gdańsk, Poland
| | - Jakub Karczewski
- Faculty of Applied Physics and Mathematics, Institute of Nanotechnology and Materials Science, Gdańsk University of Technology, Narutowicza Str. 11/12, 80-233 Gdańsk, Poland
| | - Anna Zielińska-Jurek
- Department of Process Engineering and Chemical Technology, Faculty of Chemistry, Gdańsk University of Technology, Narutowicza Str. 11/12, 80-233 Gdańsk, Poland
| | - Rafał Piątek
- Department of Molecular Biotechnology and Microbiology, Faculty of Chemistry, Gdańsk University of Technology, Narutowicza Str. 11/12, 80-233 Gdańsk, Poland
- BioTechMed Center, Gdańsk University of Technology, Narutowicza Str. 11/12, 80-233 Gdańsk, Poland
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Bahraminejad E, Paliwal D, Sunde M, Holt C, Carver JA, Thorn DC. Amyloid fibril formation by α S1- and β-casein implies that fibril formation is a general property of casein proteins. BIOCHIMICA ET BIOPHYSICA ACTA. PROTEINS AND PROTEOMICS 2022; 1870:140854. [PMID: 36087849 DOI: 10.1016/j.bbapap.2022.140854] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Revised: 08/31/2022] [Accepted: 09/02/2022] [Indexed: 06/15/2023]
Abstract
Caseins are a diverse family of intrinsically disordered proteins present in the milks of all mammals. A property common to two cow paralogues, αS2- and κ-casein, is their propensity in vitro to form amyloid fibrils, the highly ordered protein aggregates associated with many age-related, including neurological, diseases. In this study, we explored whether amyloid fibril-forming propensity is a general feature of casein proteins by examining the other cow caseins (αS1 and β) as well as β-caseins from camel and goat. Small-angle X-ray scattering measurements indicated that cow αS1- and β-casein formed large spherical aggregates at neutral pH and 20°C. Upon incubation at 65°C, αS1- and β-casein underwent conversion to amyloid fibrils over the course of ten days, as shown by thioflavin T binding, transmission electron microscopy, and X-ray fibre diffraction. At the lower temperature of 37°C where fibril formation was more limited, camel β-casein exhibited a greater fibril-forming propensity than its cow or goat orthologues. Limited proteolysis of cow and camel β-casein fibrils and analysis by mass spectrometry indicated a common amyloidogenic sequence in the proline, glutamine-rich, C-terminal region of β-casein. These findings highlight the persistence of amyloidogenic sequences within caseins, which likely contribute to their functional, heterotypic self-assembly; in all mammalian milks, at least two caseins coalesce to form casein micelles, implying that caseins diversified partly to avoid dysfunctional amyloid fibril formation.
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Affiliation(s)
- Elmira Bahraminejad
- Research School of Chemistry, The Australian National University, Acton, ACT 2601, Australia
| | - Devashi Paliwal
- Research School of Chemistry, The Australian National University, Acton, ACT 2601, Australia
| | - Margaret Sunde
- School of Medical Sciences, Faculty of Medicine and Health, and Sydney Nano, The University of Sydney, Sydney, NSW 2006, Australia
| | - Carl Holt
- Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - John A Carver
- Research School of Chemistry, The Australian National University, Acton, ACT 2601, Australia
| | - David C Thorn
- Research School of Chemistry, The Australian National University, Acton, ACT 2601, Australia.
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Rojas-Candelas LE, Chanona-Pérez JJ, Méndez JVM, Morales-Hernández JA, Benavides HAC. Characterization of Structural Changes of Casein Micelles at Different PH Using Microscopy and Spectroscopy Techniques. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2022; 28:1-10. [PMID: 35156608 DOI: 10.1017/s1431927622000162] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
This study aimed to evaluate the influence of pH changes on morphometric parameters of casein micelles and a general overview of their conformational structure through microscopy techniques, Raman spectroscopy and multivariate analysis. It was found that casein micelles morphology and protein secondary structure depend strongly upon pH. The changes of arithmetic average roughness (Ra), size, and shape of casein micelles at different pH are properly characterized by atomic force and cryo-transmission electron microscopy. Morphometric changes of casein micelles were correlated correctly with folding and unfolding of casein molecules as evaluated by Raman spectroscopy when the pH was varied. The novelty of this contribution consists in demonstrating that there is a close structure-functionality relationship between the morphometric parameters of proteins and their secondary structure. Knowledge about casein micelles can help improve their use of its diverse applications.
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Affiliation(s)
- Liliana Edith Rojas-Candelas
- Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Av. Wilfrido Massieu Esq, Cda, Miguel Stampa s/n, C.P. 07738Mexico City, Mexico
| | - José Jorge Chanona-Pérez
- Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Av. Wilfrido Massieu Esq, Cda, Miguel Stampa s/n, C.P. 07738Mexico City, Mexico
| | - Juan Vicente Méndez Méndez
- Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Av. Wilfrido Massieu Esq, Cda, Miguel Stampa s/n, C.P. 07738Mexico City, Mexico
- Centro de Nanociencias y Micro y Nanotecnologías, Instituto Politécnico Nacional, Luis Enrique Erro s/n, Zacatenco, Gustavo A. Madero, C.P. 07738Mexico City, Mexico
| | - José Antonio Morales-Hernández
- Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco (CIATEJ), A. C. Av Normalistas #800, Guadalajara, Jalisco, México
| | - Héctor Alfredo Calderón Benavides
- Instituto Politécnico Nacional. Escuela Superior de Física y Matemáticas, Av. Instituto Politécnico Nacional Edificio 9, U. Profesional Adolfo Lopez Mateos, Gustavo A. Madero, C.P. 07738Mexico City, Mexico
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7
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Active Casein Coatings and Films for Perishable Foods: Structural Properties and Shelf-Life Extension. COATINGS 2021. [DOI: 10.3390/coatings11080899] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
There is an urgent need to increase the food supplies to fulfil the demands of future generations as the population of the world is expected to grow beyond 10 billion by 2050. An essential component for ensuring global food security is to reduce food losses during the post-harvest stage. Active edible coatings and films are a promising sustainable preservation technology for shelf-life extension of food products by hindering decay kinetics of minimally processed fruits and vegetables (F&V), by restricting the mass transfer of moisture, aroma, or gases and carrying an active compound, such as an antioxidant or antimicrobial. Active protein-based coatings and films have the potential to extend the shelf-life of food products by decreasing their respiration rates, as they exhibit an excellent gas barrier and good mechanical properties as compared to other biopolymeric packaging. Among protein-based biopolymers, casein and its derivatives as packaging films have been extensively studied due to their low cost, complete biodegradability, and availability. Currently, there is no review study focusing on caseinate-based active coating and film, thus, this review aims to give insights on the composition, rheology, structure, and properties of caseinate-based formulations by critically discussing the results presented in the literature. A methodological approach was followed to obtain relevant literature to discuss the influence of additives on the shelf-life of F&V. Furthermore, changes in secondary structure of casein were observed after incorporation of bioactive compounds (i.e., phenolic acids). Likewise, there is a need to explore chemical interactions among bioactive compounds and biopolymer material by using in silico and laboratory trials as food additives have shown to influence the physicochemical properties of film and shelf-life of food products.
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8
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USANS and SANS investigations on the coagulation of commercial bovine milk: Microstructures induced by calf and fungal rennet. Food Hydrocoll 2021. [DOI: 10.1016/j.foodhyd.2021.106622] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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9
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Holt C. A quantitative calcium phosphate nanocluster model of the casein micelle: the average size, size distribution and surface properties. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2021; 50:847-866. [PMID: 33866398 DOI: 10.1007/s00249-021-01533-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 01/22/2021] [Accepted: 03/28/2021] [Indexed: 10/21/2022]
Abstract
Caseins (αS1, αS2, β and κ) are the main protein fraction of bovine milk. Together with nanoclusters of amorphous calcium phosphate (CaP) and divalent cations, they combine to form a polydisperse distribution of particles called casein micelles. A casein micelle model is proposed which is consistent with the way in which intrinsically disordered proteins interact through predominantly polar, short, linear, motifs. Using the model, an expression is derived for the size distribution of casein micelles formed when caseins bind to the CaP nanoclusters and the complexes further associate with each other and the remaining mixture of free caseins. The result is a refined coat-core model in which the core is formed mainly by the nanocluster complexes and the coat is formed exclusively by the free caseins. Example calculations of the size distribution and surface composition of an average bovine milk are compared with experiment. The average size, size distribution and surface composition of the micelles is shown to depend on the affinity of the nanocluster complexes for each other in competition with their affinity for free caseins, and on the concentrations of free caseins, calcium ions and other salts in the continuous phase.
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Affiliation(s)
- Carl Holt
- Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow, G12 8QQ, UK.
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10
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Castelletto V, Seitsonen J, Ruokolainen J, Hamley IW. Alpha helical surfactant-like peptides self-assemble into pH-dependent nanostructures. SOFT MATTER 2021; 17:3096-3104. [PMID: 33598669 DOI: 10.1039/d0sm02095h] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
A designed surfactant-like peptide is shown, using a combination of cryogenic-transmission electron microscopy and small-angle X-ray scattering, to have remarkable pH-dependent self-assembly properties. Peptide Arg3-Leu12 (R3L12) forms a network of peptide nanotubes at pH 9 and below. These are associated with α-helical conformation in a "cross-α" nanotube structure, in which peptide dimers lie perpendicular to the nanotube axis, with arginine coated inner and outer nanotube walls. In contrast, this peptide forms decorated vesicular aggregates at higher pH values, close to the pKa of the arginine residues. These structures are associated with a loss of α-helical order as detected through X-ray scattering, circular dichroism and FTIR spectroscopy, the latter technique also revealing a loss of ordering of leucine side chains. This suggests a proposed model for the decorated or patchy vesicular structures that comprises disordered peptide as the matrix of the membrane, with small domains of ordered peptide dimers forming the minority domains. We ascribe this to a lipid-raft like phase separation process, due to conformational disordering of the leucine hydrophobic chains. The observation of the self-assembly of a simple surfactant-like peptide into these types of nanostructure is remarkable, and peptide R3L12 shows unique pH-dependent morphological and conformational behaviour, with the potential for a range of future applications.
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11
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Erukainure OL, Salau VF, Alabi OO, Ebuehi OAT, Koorbanally NA, Islam MS. Casein micelles from bovine Milk exerts Neuroprotection by stalling metabolic complications linked to oxidative brain injury. Metab Brain Dis 2020; 35:1417-1428. [PMID: 32990928 DOI: 10.1007/s11011-020-00621-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 09/22/2020] [Indexed: 11/30/2022]
Abstract
Caseins are the most abundant milk proteins in mammalian species and are assembled in supra-macromolecular structures called micelles. In this study, the microstructural properties, particle size, and elemental composition of isolated casein from bovine milk and its therapeutic effect on oxidative and cholinergic activities linked to dementia in oxidative brain injury were investigated. SEM analysis of the isolated casein micelles from skimmed fresh bovine milk revealed spherical colloid aggregates, while TEM analysis revealed dispersed spherical particles with a mean size of 63.15 ± 4.77 nm. SEM-EDX analysis revealed clusters of carbon, oxygen, sulfur, copper, sodium, magnesium, potassium, iron, and selenium. Treatment of oxidative brain injury with the isolated casein micelles led to elevated levels of GSH, SOD, catalase, ENTPDase, 5'NTPase activities, while concomitantly suppressing MDA, cholesterol, HDL-c levels, acetylcholinesterase and lipase activities. Treatment with the isolated casein micelles led to complete depletion of oxidative generated lipid metabolites, while deactivating oxidative-activated lipid metabolic pathways. These results indicate the microstructural properties, particle size, elemental composition, and antioxidant neuroprotective effect of casein micelles from bovine milk. Thus, demonstrating the nutraceutical properties of milk in the management of oxidative induced cognitive impairment.
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Affiliation(s)
- Ochuko L Erukainure
- Department of Pharmacology, University of the Free State, Bloemfontein, 9300, South Africa.
| | - Veronica F Salau
- Department of Biochemistry, University of KwaZulu-Natal, Westville Campus, Durban, 4000, South Africa
| | - Opeyemi O Alabi
- Department of Food Technology, Federal University, Oye-Ekiti, Ekiti, Nigeria
| | | | - Neil A Koorbanally
- School of Chemistry and Physics, University of KwaZulu-Natal, Westville Campus, Durban, 4000, South Africa
| | - Md Shahidul Islam
- Department of Biochemistry, University of KwaZulu-Natal, Westville Campus, Durban, 4000, South Africa
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12
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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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13
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Peyronel F, Marangoni AG, Pink DA. Using the USAXS technique to reveal the fat globule and casein micelle structures of bovine dairy products. Food Res Int 2019; 129:108846. [PMID: 32036933 DOI: 10.1016/j.foodres.2019.108846] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 11/15/2019] [Accepted: 11/18/2019] [Indexed: 11/26/2022]
Abstract
Cows' milk is a commodity used worldwide to make many dairy products. We have used the ultra small angle X-ray scattering (USAXS) technique to reveal the fat globule and casein micelle structures of some dairy products. USAXS covers the q-range 5 × 10-4 Å-1 < q < 10-1 Å-1, thereby allowing the study of micron-scale structures present in those dairy products. We measured the USAXS intensity, Iq, as a function of the scattering vector magnitude, q, for samples of skim milk, non-homogenized whole milk, homogenized whole milk, half and half and heavy cream, at two temperatures, 7 °C and 45 °C. The data collected from the scattering experiments were fitted using the Unified fit model run under the IRENA software from the Advanced Photon Source, Argonne National Laboratory (Illinois, USA). The fittings were carried out when the data were plotted as log[I(q)] vs log[q]. We observed a combination of linear regions (LRs) and knees. Two parameters of interest were obtained from the fittings, a radius of gyration, Rg, and a Porod exponent, P. Unified fit allowed us to fit up to four structural levels. One of the knees was centered at q ≈ 8 × 10-3 Å-1 for all samples measured at 7 °C, but vanished at 45 °C. Two LRs were identified as being either due to casein micelles (CMs) or to fat globules (FGs). The porod exponent obtained from these LRs allowed us to describe the surface morphology of CMs and FGs. Two of the Rg values gave a rough estimate of the FGs and CMs sizes. FGs were identified for samples of homogenized whole milk, half and half and heavy cream in the q-region 2 × 10-4 < q < 8 × 10-4 Å-1. We found that, in the absence of chymosin, or changes in pH, CaCl2 concentration or temperature changes, skim milk and non-homogenized whole milk displayed a Porod exponent that indicated a behavior characteristic of aggregation. Using computer simulations, we found that, seemingly, bovine CMs spontaneously formed approximately 1-dimensional aggregates possibly analogous to swollen randomly branched polymers.
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Affiliation(s)
| | | | - David A Pink
- Physics Department, St. Francis Xavier University, Antigonish, NS, Canada; Food Science Department, University of Guelph, Guelph, ON, Canada
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14
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Che H, Zhang H, Tian Y, Lai PFH, Xia Y, Wang S, Ai L. Exopolysaccharide from Streptococcus thermophilus as stabilizer in fermented dairy: Binding kinetics and interactions with casein of milk. Int J Biol Macromol 2019; 140:1018-1025. [PMID: 31437497 DOI: 10.1016/j.ijbiomac.2019.08.146] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Revised: 08/12/2019] [Accepted: 08/17/2019] [Indexed: 01/01/2023]
Abstract
Exopolysaccharides (EPSs) from lactic acid bacteria have great effect on the quality of fermented milk products. However, the mechanism for the quality improvement has not been well described. This study aimed to investigate the molecular binding kinetics and interactions between EPS obtained from Streptococcus thermophilus AR333 (EPS333) and casein of milk (CM) in a simulated acidifying process. The results indicated that EPS333 had a significant effect on the stability of casein micelles at acidic pH (6.0-4.5) according to the turbidity, ζ-potential, particle size and distribution analysis. The adsorption-desorption study by bio-layer interferometry identified the direct affinity binding between EPS333 and CM, the interactive moiety of casein was α-casein, rather than β- or κ-casein. Fluorescence quenching analysis revealed that the force types of interaction between EPS333 and CM were dynamically changeable during the acidifying process, mainly from electrostatic interaction at pH 7.0-6.5, to hydrophobic or hydrogen bonding at pH 6.5-5.5, and then transferred to electrostatic interaction again at pH 5.5-5.0. Conclusively, EPS333 could bind with CM directly via different binding forces during acidifying process to stabilize the properties of casein micelles.
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Affiliation(s)
- Haoqi Che
- Shanghai Engineering Research Center of Food Microbiology, School of Medical Instruments and Food Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Hui Zhang
- Shanghai Engineering Research Center of Food Microbiology, School of Medical Instruments and Food Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Yanjun Tian
- Shandong Food Ferment Industry Research & Design Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250013, China
| | - Phoency F H Lai
- Shanghai Engineering Research Center of Food Microbiology, School of Medical Instruments and Food Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Yongjun Xia
- Shanghai Engineering Research Center of Food Microbiology, School of Medical Instruments and Food Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Shijie Wang
- Shijiazhuang Junlebao Dairy Co. Ltd, Shijiazhuang 050221, China
| | - Lianzhong Ai
- Shanghai Engineering Research Center of Food Microbiology, School of Medical Instruments and Food Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China.
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15
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Carver JA, Holt C. Functional and dysfunctional folding, association and aggregation of caseins. PROTEIN MISFOLDING 2019; 118:163-216. [DOI: 10.1016/bs.apcsb.2019.09.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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16
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Madende M, Kemp G, Stoychev S, Osthoff G. Characterisation of African elephant beta casein and its relevance to the chemistry of caseins and casein micelles. Int Dairy J 2018. [DOI: 10.1016/j.idairyj.2018.05.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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17
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Qu Y, Harte FM, Elias RJ, Coupland JN. Effect of ethanol on the solubilization of hydrophobic molecules by sodium caseinate. Food Hydrocoll 2018. [DOI: 10.1016/j.foodhyd.2017.10.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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18
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Boire A, Bouchoux A, Bouhallab S, Chapeau AL, Croguennec T, Ferraro V, Lechevalier V, Menut P, Pézennec S, Renard D, Santé-Lhoutellier V, Laleg K, Micard V, Riaublanc A, Anton M. Proteins for the future: A soft matter approach to link basic knowledge and innovative applications. INNOV FOOD SCI EMERG 2018. [DOI: 10.1016/j.ifset.2017.06.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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19
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Felix da Silva D, Ahrné L, Ipsen R, Hougaard AB. Casein-Based Powders: Characteristics and Rehydration Properties. Compr Rev Food Sci Food Saf 2017; 17:240-254. [DOI: 10.1111/1541-4337.12319] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 10/13/2017] [Accepted: 10/13/2017] [Indexed: 11/28/2022]
Affiliation(s)
- Denise Felix da Silva
- Dept. of Food Science, Faculty of Science; Univ. of Copenhagen; Rolighedsvej 26 DK-1958 Frederiksberg C Denmark
| | - Lilia Ahrné
- Dept. of Food Science, Faculty of Science; Univ. of Copenhagen; Rolighedsvej 26 DK-1958 Frederiksberg C Denmark
| | - Richard Ipsen
- Dept. of Food Science, Faculty of Science; Univ. of Copenhagen; Rolighedsvej 26 DK-1958 Frederiksberg C Denmark
| | - Anni Bygvraa Hougaard
- Dept. of Food Science, Faculty of Science; Univ. of Copenhagen; Rolighedsvej 26 DK-1958 Frederiksberg C Denmark
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20
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Shayeh JS, Sefidbakht Y, Siadat SOR, Niknam K. Continuous fast Fourier transforms cyclic voltammetry as a new approach for investigation of skim milk k-casein proteolysis, a comparative study. Int J Biol Macromol 2017; 103:972-977. [DOI: 10.1016/j.ijbiomac.2017.05.112] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 05/09/2017] [Accepted: 05/15/2017] [Indexed: 11/26/2022]
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21
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Milk Protein Polymer and Its Application in Environmentally Safe Adhesives. Polymers (Basel) 2016; 8:polym8090324. [PMID: 30974597 PMCID: PMC6432148 DOI: 10.3390/polym8090324] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2016] [Revised: 08/22/2016] [Accepted: 08/23/2016] [Indexed: 11/17/2022] Open
Abstract
Milk proteins (caseins and whey proteins) are important protein sources for human nutrition; in addition, they possess important natural polymers. These protein molecules can be modified by physical, chemical, and/or enzymatic means. Casein is one of the oldest natural polymers, used for adhesives, dating back to thousands years ago. Research on milk-protein-based adhesives is still ongoing. This article deals with the chemistry and structure of milk protein polymers, and examples of uses in environmentally-safe adhesives. These are promising routes in the exploration of the broad application of milk proteins.
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22
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23
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Morales R, Martinez M, Pilosof A. Impact of casein glycomacropeptide on sodium caseinate self-assembly and gelation. Int Dairy J 2015. [DOI: 10.1016/j.idairyj.2015.04.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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24
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Milkovska-Stamenova S, Hoffmann R. Identification and quantification of bovine protein lactosylation sites in different milk products. J Proteomics 2015. [PMID: 26210590 DOI: 10.1016/j.jprot.2015.07.021] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
UNLABELLED The microbiological safety of milk is typically guaranteed by thermal treatments, such as pasteurization and ultra high temperature (UHT) treatment, whereas infant formula (IF) is often produced at even harsher conditions including a drying process. Thermal treatments have raised concerns, as they may denature proteins and initiate protein modifications. Previous studies identified already many lactosylation sites in milk and showed that the lactosylation degree of some proteins correlates to thermal treatment conditions. Here, we studied the glycation degrees of 124 lactosylation sites in 28 bovine milk proteins in raw milk, three brands of pasteurized milk, three brands of UHT milk, and five brands of IF. Whereas, the glycation degree of many lactosylation sites increased from raw milk, to pasteurized milk, UHT milk, and IF, several modification sites showed a different behavior indicating that global measures do not correctly reflect the reactivity of distinct sites. Interestingly, the glycation degrees varied considerably among the brands of UHT milk and IF indicating that specific production processes of a company have to be considered and not only the classification of milk as pasteurized or UHT. Thus, proper adjustments of the technical processes should allow reducing the lactosylation levels in both UHT milk and IF. SIGNIFICANCE It is well established that thermal treatment of milk triggers protein modifications, such as lactosylation of lysine residues in several proteins, although the extent of lactosylation has not been quantitatively compared for a broad panel of protein lactosylation sites among different commercial products. The current study extends previous reports by relatively quantifying 124 confirmed lactosylation sites in 28 bovine milk proteins including several low abundant proteins. Whereas, glycation is generally assumed to be an unspecific chemical reaction with the modification degrees depending on the protein and sugar concentrations, we could show that each protein and even each lactosylation site in a given protein is differently affected by thermal processes indicating that the global lactosylation degrees will not allow predicting the influence of a technical process on individual proteins and lactosylation sites. Additionally, we could show that brands of each milk product differ significantly in their glycation degrees with UHT milk brands for example spanning the whole range from the relatively low lactosylation degree of pasteurized milk to the rather high lactosylation degree of IF. Similar differences were obtained for IF that generally showed the highest glycation degree. The targeted quantification approach established and validated here will be useful to reveal technical processing steps that trigger individual lactosylation sites and thus can help to prevent such unwanted reactions. Even slight changes of the technical processes might allow reducing the lactosylation degree of milk proteins significantly without challenging the microbiological safety or affecting consumer behavior.
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Affiliation(s)
- Sanja Milkovska-Stamenova
- Deutscher Platz 5, 04103 Leipzig, Germany; Institute of Bioanalytical Chemistry, Faculty of Chemistry and Mineralogy, Universität Leipzig, Germany; Center for Biotechnology and Biomedicine, Universität Leipzig, Germany
| | - Ralf Hoffmann
- Deutscher Platz 5, 04103 Leipzig, Germany; Institute of Bioanalytical Chemistry, Faculty of Chemistry and Mineralogy, Universität Leipzig, Germany; Center for Biotechnology and Biomedicine, Universität Leipzig, Germany.
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25
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Mahendran V, Sangeetha J, Philip J. Probing of Competitive Displacement Adsorption of Casein at Oil-in-Water Interface Using Equilibrium Force Distance Measurements. J Phys Chem B 2015; 119:6828-35. [DOI: 10.1021/acs.jpcb.5b02612] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- V. Mahendran
- SMARTS, Metallurgy
and Materials Group,
Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu, India
| | - J. Sangeetha
- SMARTS, Metallurgy
and Materials Group,
Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu, India
| | - John Philip
- SMARTS, Metallurgy
and Materials Group,
Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu, India
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26
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Broyard C, Gaucheron F. Modifications of structures and functions of caseins: a scientific and technological challenge. ACTA ACUST UNITED AC 2015. [DOI: 10.1007/s13594-015-0220-y] [Citation(s) in RCA: 162] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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27
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Longitudinal analysis of protein glycosylation and β-casein phosphorylation in term and preterm human milk during the first 2 months of lactation. Br J Nutr 2012. [PMID: 23182305 DOI: 10.1017/s0007114512004588] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Human milk proteins provide term and preterm infants with both nutrition and protection. The objective of the present study was to examine longitudinal changes in the protein composition of term and preterm milk during the first 2 months of lactation, focusing on protein phosphorylation and glycosylation. Using gel electrophoresis, the relative concentration and glycosylation status of lactoferrin, secretory Ig A, β-casein, α-lactalbumin, serum albumin, bile salt-stimulated lipase, xanthine oxidoreductase, tenascin and macrophage mannose receptor 1 were measured in milk collected on days 7, 10, 14, 18, 21, 28 and 60 postpartum from preterm mothers (28-32 weeks gestation, n 17). The phosphorylation status of β-casein was also investigated. To determine if these variables differ in term and preterm milk, samples from term mothers (38-41 weeks gestation, n 8) collected on days 7, 14 and 30 of lactation were also analysed. The concentration of the abundant milk proteins decreased during lactation in term and preterm milk (P <0·05). No difference in protein glycosylation was observed, except for the glycoproteins serum albumin and tenascin. The phosphorylation of β-casein varied significantly between term and preterm milk. Further investigation is required to determine whether these modifications affect protein function and are clinically important to preterm infants.
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28
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κ-Casein terminates casein micelle build-up by its “soft” secondary structure. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2012; 41:959-68. [DOI: 10.1007/s00249-012-0854-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Revised: 06/11/2012] [Accepted: 06/11/2012] [Indexed: 10/27/2022]
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29
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Sangeetha J, Philip J. The interaction, stability and response to an external stimulus of iron oxide nanoparticle–casein nanocomplexes. Colloids Surf A Physicochem Eng Asp 2012. [DOI: 10.1016/j.colsurfa.2012.04.049] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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30
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Chemical modifications of casein occurring during industrial manufacturing of milk protein powders. Eur Food Res Technol 2012. [DOI: 10.1007/s00217-012-1760-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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31
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Toward an integrated modeling of the dairy product transformations, a review of the existing mathematical models. Food Hydrocoll 2012. [DOI: 10.1016/j.foodhyd.2011.08.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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32
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Trejo R, Dokland T, Jurat-Fuentes J, Harte F. Cryo-transmission electron tomography of native casein micelles from bovine milk. J Dairy Sci 2012; 94:5770-5. [PMID: 22118067 DOI: 10.3168/jds.2011-4368] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Accepted: 08/16/2011] [Indexed: 11/19/2022]
Abstract
Caseins are the principal protein components in milk and an important ingredient in the food industry. In liquid milk, caseins are found as micelles of casein proteins and colloidal calcium nanoclusters. Casein micelles were isolated from raw skim milk by size exclusion chromatography and suspended in milk protein-free serum produced by ultrafiltration (molecular weight cut-off of 3 kDa) of raw skim milk. The micelles were imaged by cryo-electron microscopy and subjected to tomographic reconstruction methods to visualize the 3-dimensional and internal organization of native casein micelles. This provided new insights into the internal architecture of the casein micelle that had not been apparent from prior cryo-transmission electron microscopy studies. This analysis demonstrated the presence of water-filled cavities (∼20 to 30 nm in diameter), channels (diameter greater than ∼5 nm), and several hundred high-density nanoclusters (6 to 12 nm in diameter) within the interior of the micelles. No spherical protein submicellar structures were observed.
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Affiliation(s)
- R Trejo
- Department of Food Science and Technology, The University of Tennessee, Knoxville 37996-4539, USA
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33
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Panagopoulou MA, Stergiou DV, Roussis IG, Panayotou G, Prodromidis MI. Kappa-casein based electrochemical and surface plasmon resonance biosensors for the assessment of the clotting activity of rennet. Anal Chim Acta 2012; 712:132-7. [DOI: 10.1016/j.aca.2011.11.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Revised: 10/26/2011] [Accepted: 11/02/2011] [Indexed: 11/17/2022]
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34
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Choi J, Horne DS, Lucey JA. Determination of molecular weight of a purified fraction of colloidal calcium phosphate derived from the casein micelles of bovine milk. J Dairy Sci 2011; 94:3250-61. [PMID: 21700009 DOI: 10.3168/jds.2010-3762] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Accepted: 03/17/2011] [Indexed: 11/19/2022]
Abstract
Colloidal calcium phosphate (CCP) plays a key role in the formation and integrity of casein (CN) micelles. However, limited information is available on the molecular weight (M(w)) of CCP. Recently, we theoretically derived the M(w) of CCP and the objectives of this study were to experimentally determine the M(w) of CCP. We used 2 methods to prepare CCP fractions: skim milk was enzymatically digested with either trypsin or a combination of papain and proteinase enzymes to remove most CN. The CN phosphopeptides are resistant to trypsin hydrolysis. Digestion was carried out in a membrane tube that was dialyzed against the same bulk milk used in sample preparation to remove small peptides and to minimize perturbation of CCP. After digestion, the protein contents of the enzyme-treated milks were 0.92 and 0.36% for the trypsin and papain-proteinase treatments, respectively. Size-exclusion chromatography, coupled with multi-angle laser light scattering, was used to separate the CCP-phosphopeptide fraction from the digested mixture. Simulated milk ultrafiltrate was used as a mobile phase during size-exclusion chromatography separation to try to preserve the integrity of CCP. Size-exclusion chromatography peaks, which had higher Ca and P contents than the baseline, were identified as the likely fractions containing the phosphopeptide-stabilized CCP; this peak eluted with retention times of 100 to approximately 110 min for trypsinated samples. The papain-proteinase treatment caused excessive loss of CN that were needed to stabilize CCP, which resulted in no obvious peak that had elevated Ca and P contents. Debye plots at these retention times indicated that the weight-average M(w) for the fraction prepared by trypsin was 17,450 g/mol. Attempts to estimate the M(w) of the phosphopeptides associated with CCP using sodium dodecyl sulfate-PAGE were not successful, as we did not observe any peptide bands in these gels, presumably because of their low concentration in the isolated, unconcentrated fraction. Assuming that 4 CN phosphopeptides stabilized each CCP and if the M(w) of each of these phosphopeptides was about 2,500 g/mol, then the M(w) of CCP would be around 7,450 g/mol. This experimental value was close to the theoretically-derived M(w) of 4,897 and 9,757 g/mol for tetrahedron and bi-pyramid shaped objects, respectively, when using the brushite form of calcium phosphate.
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Affiliation(s)
- J Choi
- Department of Food Science, University of Wisconsin-Madison, 1605 Linden Drive, Madison 53706, USA
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35
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Elzoghby AO, Abo El-Fotoh WS, Elgindy NA. Casein-based formulations as promising controlled release drug delivery systems. J Control Release 2011; 153:206-16. [DOI: 10.1016/j.jconrel.2011.02.010] [Citation(s) in RCA: 334] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2010] [Accepted: 02/09/2011] [Indexed: 01/06/2023]
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36
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Panagopoulou MA, Stergiou DV, Roussis IG, Prodromidis MI. Impedimetric biosensor for the assessment of the clotting activity of rennet. Anal Chem 2011; 82:8629-36. [PMID: 20845927 DOI: 10.1021/ac1017925] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cheese production is relied upon the action of rennet (a mixture of chymosin and pepsin) onto casein micelles of milk. For the first time, the monitoring of this interaction with electrochemical impedance spectroscopy (EIS) was used to develop a faradic impedimetric biosensor for the assessment of the clotting activity of rennet, using hexacyanoferrate(II)/(III) couple as a redox probe. Gold electrodes were modified with self-assembled monolayers of different thiols (thioctic acid, dithiobis-N-succinimidyl propionate, and cysteamine), and (artificial) casein micelles were immobilized on the modified gold surfaces. The proposed method is based on the measurement of charge-transfer resistance (R(ct)) changes attributed to the degradation of the negatively charged immobilized casein micelles by rennet to neutral biostructures. This action results in the increase of the flux of the redox probe, which exists in the bulk solution, to the surface of the electrode and, consequently, in the decrease of R(ct). Experimental parameters such as the micelle loading, the reaction time, the concentration of rennet, and the working pH, were optimized. Besides EIS measurements, cyclic voltammetry, FT-IR, and atomic force microscopy (AFM) experiments were also performed before and after the interaction of the immobilized micelles with rennet. Finally, the proposed biosensors were successfully tried for various commercial samples.
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Affiliation(s)
- Maria A Panagopoulou
- Laboratory of Analytical Chemistry, Department of Chemistry, University of Ioannina, 451 10 Ioannina, Greece
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37
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Olivares M, Passeggi M, Ferrón J, Zorrilla S, Rubiolo A. Study of milk/κ-carrageenan mixtures by atomic force microscopy. Food Hydrocoll 2010. [DOI: 10.1016/j.foodhyd.2010.04.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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38
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39
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Dahbi L, Alexander M, Trappe V, Dhont J, Schurtenberger P. Rheology and structural arrest of casein suspensions. J Colloid Interface Sci 2010; 342:564-70. [DOI: 10.1016/j.jcis.2009.10.042] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Revised: 10/18/2009] [Accepted: 10/20/2009] [Indexed: 10/20/2022]
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40
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41
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Bouchoux A, Cayemitte PE, Jardin J, Gésan-Guiziou G, Cabane B. Casein micelle dispersions under osmotic stress. Biophys J 2009; 96:693-706. [PMID: 19167314 DOI: 10.1016/j.bpj.2008.10.006] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2008] [Accepted: 10/08/2008] [Indexed: 11/19/2022] Open
Abstract
Casein micelles dispersions have been concentrated and equilibrated at different osmotic pressures using equilibrium dialysis. This technique measured an equation of state of the dispersions over a wide range of pressures and concentrations and at different ionic strengths. Three regimes were found. i), A dilute regime in which the osmotic pressure is proportional to the casein concentration. In this regime, the casein micelles are well separated and rarely interact, whereas the osmotic pressure is dominated by the contribution from small residual peptides that are dissolved in the aqueous phase. ii), A transition range that starts when the casein micelles begin to interact through their kappa-casein brushes and ends when the micelles are forced to get into contact with each other. At the end of this regime, the dispersions behave as coherent solids that do not fully redisperse when osmotic stress is released. iii), A concentrated regime in which compression removes water from within the micelles, and increases the fraction of micelles that are irreversibly linked to each other. In this regime the osmotic pressure profile is a power law of the residual free volume. It is well described by a simple model that considers the micelle to be made of dense regions separated by a continuous phase. The amount of water in the dense regions matches the usual hydration of proteins.
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