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Raynes JK, Mata J, Wilde KL, Carver JA, Kelly SM, Holt C. Structure of biomimetic casein micelles: Critical tests of the hydrophobic colloid and multivalent-binding models using recombinant deuterated and phosphorylated β-casein. J Struct Biol X 2024; 9:100096. [PMID: 38318529 PMCID: PMC10840362 DOI: 10.1016/j.yjsbx.2024.100096] [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: 10/19/2023] [Revised: 01/08/2024] [Accepted: 01/17/2024] [Indexed: 02/07/2024] Open
Abstract
Milk contains high concentrations of amyloidogenic casein proteins and is supersaturated with respect to crystalline calcium phosphates such as apatite. Nevertheless, the mammary gland normally remains unmineralized and free of amyloid. Unlike κ-casein, β- and αS-caseins are highly effective mineral chaperones that prevent ectopic and pathological calcification of the mammary gland. Milk invariably contains a mixture of two to five different caseins that act on each other as molecular chaperones. Instead of forming amyloid fibrils, several thousand caseins and hundreds of nanoclusters of amorphous calcium phosphate combine to form fuzzy complexes called casein micelles. To understand the biological functions of the casein micelle its structure needs to be understood better than at present. The location in micelles of the highly amyloidogenic κ-casein is disputed. In traditional hydrophobic colloid models, it, alone, forms a stabilizing surface coat that also determines the average size of the micelles. In the recent multivalent-binding model, κ-casein is present throughout the micelle, in intimate contact with the other caseins. To discriminate between these models, a range of biomimetic micelles was prepared using a fixed concentration of the mineral chaperone β-casein and nanoclusters of calcium phosphate, with variable concentrations of κ-casein. A biomimetic micelle was also prepared using a highly deuterated and in vivo phosphorylated recombinant β-casein with calcium phosphate and unlabelled κ-casein. Neutron and X-ray scattering experiments revealed that κ-casein is distributed throughout the micelle, in quantitative agreement with the multivalent-binding model but contrary to the hydrophobic colloid models.
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Affiliation(s)
- Jared K. Raynes
- CSIRO Agriculture & Food, 671 Sneydes Road, Werribee, VIC 3031, Australia
- All G Foods, Waterloo, NSW 2006, Australia
| | - Jitendra Mata
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW 2234, Australia
- School of Chemistry, University of New South Wales, Sydney 2052, Australia
| | - Karyn L. Wilde
- National Deuteration Facility, Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW 2234, Australia
| | - John A. Carver
- Research School of Chemistry, The Australian National University, Acton, ACT 2601, Australia
| | - Sharon M. Kelly
- School of Molecular Biosciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Carl Holt
- School of Molecular Biosciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom
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2
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Narayanan T. Recent advances in synchrotron scattering methods for probing the structure and dynamics of colloids. Adv Colloid Interface Sci 2024; 325:103114. [PMID: 38452431 DOI: 10.1016/j.cis.2024.103114] [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: 09/29/2023] [Revised: 02/07/2024] [Accepted: 02/14/2024] [Indexed: 03/09/2024]
Abstract
Recent progress in synchrotron based X-ray scattering methods applied to colloid science is reviewed. An important figure of merit of these techniques is that they enable in situ investigations of colloidal systems under the desired thermophysical and rheological conditions. An ensemble averaged simultaneous structural and dynamical information can be derived albeit in reciprocal space. Significant improvements in X-ray source brilliance and advances in detector technology have overcome some of the limitations in the past. Notably coherent X-ray scattering techniques have become more competitive and they provide complementary information to laboratory based real space methods. For a system with sufficient scattering contrast, size ranges from nm to several μm and time scales down to μs are now amenable to X-ray scattering investigations. A wide variety of sample environments can be combined with scattering experiments further enriching the science that could be pursued by means of advanced X-ray scattering instruments. Some of these recent progresses are illustrated via representative examples. To derive quantitative information from the scattering data, rigorous data analysis or modeling is required. Development of powerful computational tools including the use of artificial intelligence have become the emerging trend.
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3
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Hewa Nadugala B, Hepworth G, Mazzonetto M, Nebl T, Pagel CN, Raynes JK, Ranadheera CS, Logan A. Effect of composition, casein genetic variants and glycosylation degree on bovine milk whipping properties. Food Res Int 2024; 179:113949. [PMID: 38342518 DOI: 10.1016/j.foodres.2024.113949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Revised: 12/21/2023] [Accepted: 01/02/2024] [Indexed: 02/13/2024]
Abstract
This study investigated the individual and combined effects of ĸ-Casein (ĸ-CN; AA, AB, BB), β-Casein (β-CN; A1A1, A1A2, A2A2) and high and low ratios of glycosylated ĸ-CN to total ĸ-CN, referred to as the glycosylation degree (GD), on bovine cream whipping properties. The genetic variants of individual cows were identified using reversed-phase high-performance liquid chromatography (RP-HPLC) and verified through liquid chromatography-mass spectrometry (LC-MS). A previously discovered relationship between days-in-milk and GD was validated and used to obtain high and low GD milk. Whipped creams were created through the mechanical agitation of fat standardised cream from milk of different ĸ-CN, β-CN, and GD combinations, and whipping properties (the ability to whip, overrun, whipping time and firmness) were evaluated. No significant correlation was measured in whipping properties for cream samples from milks with different ĸ-CN and β-CN genetic variants. However, 80 % of samples exhibiting good whipping properties (i.e., the production of a stiffened peak) were from milk with low GD suggesting a correlation between whipping properties and levels of glycosylation. Moreover, cream separated from skim milk of larger casein micelle size showed superior whipping properties with shorter whipping times (<5 min), and higher firmness and overrun. Milk fat globule (MFG) size, on the other hand, did not affect whipping properties. Results indicate that the GD of κ-CN and casein micelle size may play a role in MFG adsorption at the protein and air interface of air bubbles formed during whipping; hence, they govern the dynamics of fat network formation and influencing whipping properties.
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Affiliation(s)
- Barana Hewa Nadugala
- School of Agriculture, Food & Ecosystem Sciences, Faculty of Science, University of Melbourne, VIC 3010, Australia; CSIRO Agriculture and Food, Werribee, Victoria 3030, Australia.
| | - Graham Hepworth
- Statistical Consulting Centre, The University of Melbourne, Parkville, Victoria 3010, Australia.
| | | | - Tom Nebl
- Biology Group, Biomedical Manufacturing Program, CSIRO, Clayton, VIC 3168, Australia.
| | - Charles N Pagel
- Melbourne Veterinary School, Faculty of Science, The University of Melbourne, VIC 3010, Australia.
| | | | - C S Ranadheera
- School of Agriculture, Food & Ecosystem Sciences, Faculty of Science, University of Melbourne, VIC 3010, Australia.
| | - Amy Logan
- CSIRO Agriculture and Food, Werribee, Victoria 3030, Australia.
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4
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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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5
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Ren J, Liao M, Li K, Chen F, Hu X, Ma L, Ji J. The aggregation of casein micelles induced by Ca 2+ during in vitro digestion: effects on the release of loaded anthocyanins. Food Funct 2024; 15:503-515. [PMID: 38164698 DOI: 10.1039/d3fo03684g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
Colloidal calcium phosphate (CCP) confers a modifiable structure to micellar casein (MC), which endows it with potential advantages as a delivery carrier. However, it is difficult to achieve multipattern release of the core material in the intestine with MC as a single wall. In this study, we prepared an anthocyanin-casein-based delivery system utilizing MC with different freezing degrees as the wall material with the objective of achieving the controlled release of anthocyanin as the model core in the intestine. The results showed that freezing could significantly reduce the CCP level up to 50%. Static in vitro simulated digestion with the addition of exogenous Ca2+ showed that the designed delivery system exhibited low anthocyanin release (15%-35%) in the gastric tract. The pattern of release in the intestine depended on the CCP dissociation degree. High and low dissociation degrees corresponded to slow release (from 15% to 65% within 2 h) and burst release (from 35% to 90% within 5 min), respectively. WAXS/SAXS analysis revealed that exogenous serum Ca2+ inherent in simulated gastric fluid and endogenous serum Ca2+ induced by CCP dissociation was synergistically involved in the reconstitution of CCP-mediated nanoclusters and large aggregates. The freezing degree of MC determined the endogenous serum Ca2+ level, which influenced the gastric aggregation behavior of wall MC and ultimately led to a fairly different gastrointestinal release behavior of anthocyanins.
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Affiliation(s)
- Jinbo Ren
- College of Food Science and Nutritional Engineering, National Engineering Research Center for Fruit and Vegetable Processing, China Agricultural University, Key Lab of Fruit and Vegetable Processing, Ministry of Agriculture and Rural Affairs, Beijing 100083, China.
- Xinghua Industrial Research Centre for Food Science and Human Health, China Agricultural University, Xinghua 225700, China.
| | - Minjie Liao
- College of Food Science and Nutritional Engineering, National Engineering Research Center for Fruit and Vegetable Processing, China Agricultural University, Key Lab of Fruit and Vegetable Processing, Ministry of Agriculture and Rural Affairs, Beijing 100083, China.
| | - Kaixin Li
- College of Food Science and Nutritional Engineering, National Engineering Research Center for Fruit and Vegetable Processing, China Agricultural University, Key Lab of Fruit and Vegetable Processing, Ministry of Agriculture and Rural Affairs, Beijing 100083, China.
| | - Fang Chen
- College of Food Science and Nutritional Engineering, National Engineering Research Center for Fruit and Vegetable Processing, China Agricultural University, Key Lab of Fruit and Vegetable Processing, Ministry of Agriculture and Rural Affairs, Beijing 100083, China.
| | - Xiaosong Hu
- College of Food Science and Nutritional Engineering, National Engineering Research Center for Fruit and Vegetable Processing, China Agricultural University, Key Lab of Fruit and Vegetable Processing, Ministry of Agriculture and Rural Affairs, Beijing 100083, China.
- Xinghua Industrial Research Centre for Food Science and Human Health, China Agricultural University, Xinghua 225700, China.
| | - Lingjun Ma
- College of Food Science and Nutritional Engineering, National Engineering Research Center for Fruit and Vegetable Processing, China Agricultural University, Key Lab of Fruit and Vegetable Processing, Ministry of Agriculture and Rural Affairs, Beijing 100083, China.
- Xinghua Industrial Research Centre for Food Science and Human Health, China Agricultural University, Xinghua 225700, China.
| | - Junfu Ji
- College of Food Science and Nutritional Engineering, National Engineering Research Center for Fruit and Vegetable Processing, China Agricultural University, Key Lab of Fruit and Vegetable Processing, Ministry of Agriculture and Rural Affairs, Beijing 100083, China.
- Xinghua Industrial Research Centre for Food Science and Human Health, China Agricultural University, Xinghua 225700, China.
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6
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Bayrak M, Mata J, Conn C, Floury J, Logan A. Application of small angle scattering (SAS) in structural characterisation of casein and casein-based products during digestion. Food Res Int 2023; 169:112810. [PMID: 37254386 DOI: 10.1016/j.foodres.2023.112810] [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: 12/22/2022] [Revised: 03/01/2023] [Accepted: 04/11/2023] [Indexed: 06/01/2023]
Abstract
In recent years, small and ultra-small angle scattering techniques, collectively known as small angle scattering (SAS) have been used to study various food structures during the digestion process. These techniques play an important role in structural characterisation due to the non-destructive nature (especially when using neutrons), various in situ capabilities and a large length scale (of 1 nm to ∼20 μm) they cover. The application of these techniques in the structural characterisation of dairy products has expanded significantly in recent years. Casein, a major dairy protein, forms the basis of a wide range of gel structures at different length scales. These gel structures have been extensively researched utilising scattering techniques to obtain structural information at the nano and micron scale that complements electron and confocal microscopy. Especially, neutrons have provided opportunity to study these gels in their natural environment by using various in situ options. One such example is understanding changes in casein gel structures during digestion in the gastrointestinal tract, which is essential for designing personalised food structures for a wide range of food-related diseases and improve health outcomes. In this review, we present an overview of casein gels investigated using small angle and ultra-small angle scattering techniques. We also reviewed their digestion using newly built setups recently employed in various research. To gain a greater understanding of micro and nano-scale structural changes during digestion, such as the effect of digestive juices and mechanical breakdown on structure, new setups for semi-solid food materials are needed to be optimised.
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Affiliation(s)
- Meltem Bayrak
- CSIRO Agriculture and Food, 671 Sneydes Road, Werribee, Victoria 3030, Australia; School of Science, College of Science, Engineering and Health, RMIT University, 124 La Trobe Street, Melbourne, VIC 3000, Australia.
| | - Jitendra Mata
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW 2234, Australia.
| | - Charlotte Conn
- School of Science, College of Science, Engineering and Health, RMIT University, 124 La Trobe Street, Melbourne, VIC 3000, Australia.
| | | | - Amy Logan
- CSIRO Agriculture and Food, 671 Sneydes Road, Werribee, Victoria 3030, Australia.
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7
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Heiden-Hecht T, Wu B, Appavou MS, Förster S, Frielinghaus H, Holderer O. Multiscale Structural Insight into Dairy Products and Plant-Based Alternatives by Scattering and Imaging Techniques. Foods 2023; 12:foods12102021. [PMID: 37238839 DOI: 10.3390/foods12102021] [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: 04/05/2023] [Revised: 05/11/2023] [Accepted: 05/14/2023] [Indexed: 05/28/2023] Open
Abstract
Dairy products and plant-based alternatives have a large range of structural features from atomic to macroscopic length scales. Scattering techniques with neutrons and X-rays provide a unique view into this fascinating world of interfaces and networks provided by, e.g., proteins and lipids. Combining these scattering techniques with a microscopic view into the emulsion and gel systems with environmental scanning electron microscopy (ESEM) assists in a thorough understanding of such systems. Different dairy products, such as milk, or plant-based alternatives, such as milk-imitating drinks, and their derived or even fermented products, including cheese and yogurt, are characterized in terms of their structure on nanometer- to micrometer-length scales. For dairy products, the identified structural features are milk fat globules, casein micelles, CCP nanoclusters, and milk fat crystals. With increasing dry matter content in dairy products, milk fat crystals are identified, whereas casein micelles are non-detectable due to the protein gel network in all types of cheese. For the more inhomogeneous plant-based alternatives, fat crystals, starch structures, and potentially protein structures are identified. These results may function as a base for improving the understanding of dairy products and plant-based alternatives, and may lead to enhanced plant-based alternatives in terms of structure and, thus, sensory aspects such as mouthfeel and texture.
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Affiliation(s)
- Theresia Heiden-Hecht
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Lichtenbergstr. 1, 85747 Garching, Germany
| | - Baohu Wu
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Lichtenbergstr. 1, 85747 Garching, Germany
| | - Marie-Sousai Appavou
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Lichtenbergstr. 1, 85747 Garching, Germany
| | - Stephan Förster
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Lichtenbergstr. 1, 85747 Garching, Germany
- Jülich Centre for Neutron Science (JCNS-1), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Henrich Frielinghaus
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Lichtenbergstr. 1, 85747 Garching, Germany
| | - Olaf Holderer
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Lichtenbergstr. 1, 85747 Garching, Germany
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8
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Innovative prediction of milk microbiological quality from pH measurements by digital imaging photometry. J Food Compost Anal 2022. [DOI: 10.1016/j.jfca.2022.104715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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9
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Du Z, Xu N, Yang Y, Li G, Tai Z, Li N, Sun Y. Study on internal structure of casein micelles in reconstituted skim milk powder. Int J Biol Macromol 2022; 224:437-452. [DOI: 10.1016/j.ijbiomac.2022.10.135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 10/09/2022] [Accepted: 10/15/2022] [Indexed: 11/05/2022]
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10
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In situ SAXS study of non-fat milk model systems during heat treatment and acidification. Food Res Int 2022; 157:111292. [DOI: 10.1016/j.foodres.2022.111292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 04/20/2022] [Accepted: 04/21/2022] [Indexed: 11/20/2022]
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11
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Sun Y, Tai Z, Yan T, Dai Y, Hemar Y, Li N. Unveiling the structure of the primary caseinate particle using small-angle X-ray scattering and simulation methodologies. Food Res Int 2021; 149:110653. [PMID: 34600655 DOI: 10.1016/j.foodres.2021.110653] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 08/11/2021] [Accepted: 08/17/2021] [Indexed: 11/27/2022]
Abstract
The low-resolution structure of casein (CN) clusters in sodium caseinate (NaCas) solution and its conformational dynamics were obtained by size-exclusion chromatography (SEC), analytical ultracentrifugation (AUC), small-angle X-ray scattering (SAXS), and molecular dynamics (MD) simulations. The results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and native PAGE revealed that the casein clusters consisted predominantly of α- and β-CN complexes, and a trace amount of κ-CN. The AUC analysis indicated that the casein clusters were composed of 34.6% of casein monomers, 19.2%, 20.4%, and 25.8% of complexes with molar weight (Mw) of ~50.3, ~70.6, and ~133 kDa, respectively. The volume fractions of components in casein clusters were quantified as 64.3% of αs1-β-αs2-CN, 22.3% of αs1-CN, 8.5% of αs2-CN, and 4.4% of αs1-αs2-CN, respectively. The ensemble optimization method (EOM) gave a fitting result where αs1-β-αs2-CN species coexisted in ~35.3% under compact conformation and ~64.7% in elongated conformation in solution. The three-dimensional structures of αs1-β-αs2-CN from EOM showed a good overlay on the casein clusters ab initio model obtained from DAMMIN and DAMMIX program. MD simulations revealed that αs1-β-αs2-CN underwent a conformational change from the elongated state into the compact state within the initial 200 ns of simulations. The addition of nonionic surfactants affected little the backbone-to-backbone interactions in the formation of the casein clusters. We propose that αs1-CN, β-CN, αs2-CN, and κ-CN associated in consecutive steps into casein clusters, and a trace of κ-CN may be located at the surface of the assemblies limiting the growth of casein aggregates.
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Affiliation(s)
- Yang Sun
- College of Vocational and Technical Education, Yunnan Normal University, Yieryi Avenue, No. 298, 650092 Kunming, Yunnan, People's Republic of China.
| | - Zhonghong Tai
- College of Vocational and Technical Education, Yunnan Normal University, Yieryi Avenue, No. 298, 650092 Kunming, Yunnan, People's Republic of China
| | - Tingting Yan
- College of Vocational and Technical Education, Yunnan Normal University, Yieryi Avenue, No. 298, 650092 Kunming, Yunnan, People's Republic of China
| | - Yiqi Dai
- College of Vocational and Technical Education, Yunnan Normal University, Yieryi Avenue, No. 298, 650092 Kunming, Yunnan, People's Republic of China
| | - Yacine Hemar
- Catalyst Tec Limited., 16 Beatrice Tinsley Cresecnt, Rosedale 0632, Auckland, New Zealand; International Joint Research Laboratory for Functional Dairy Protein Ingredients, U.S.-China, People's Republic of China
| | - Na Li
- National Facility for Protein Science in Shanghai, Zhangjiang Lab, Shanghai Advanced Research Institute, CAS, No.333, Haike Road, Shanghai, Shanghai 201210, People's Republic of China.
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12
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Christiansen MV, Smith GN, Brok ES, Schmiele M, Ahrné L. The relationship between ultra-small-angle X-ray scattering and viscosity measurements of casein micelles in skim milk concentrates. Food Res Int 2021; 147:110451. [PMID: 34399453 DOI: 10.1016/j.foodres.2021.110451] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 04/26/2021] [Accepted: 05/21/2021] [Indexed: 11/16/2022]
Abstract
Skim milk concentrates have important applications in the dairy industry, often as intermediate ingredients. Concentration of skim milk by reverse osmosis membrane filtration induces water removal, which reduces the free volume between the colloidal components, in particular the casein micelles. Thermal treatment before or after concentration impacts the morphology of casein micelles. These changes affect the flow behavior and viscosity, but the consequences for supermicellar structure have not been elucidated. In the present study, skim milk concentrates with different total solid contents from 8.7% (control) up to 22.8% (w/w), prepared by reverse osmosis membrane filtration of non-heated and pasteurized skim milk, were heat treated at 75 °C for 18 s, and compared with non-heated concentrates. The structure of the concentrates was studied using Ultra Small Angle X-ray Scattering (USAXS), and the viscosity of concentrates was measured. The USAXS intensity I(q) was fitted at small and intermediate q-regions (0.0005 < q < 0.003 Å-1 and 0.0035 < q < 0.03 Å-1, respectively) with a power law. The value of the power law exponent was used to assess the heat- and concentration-induced aggregation of the milk solids and correlate it with the apparent viscosity. The results showed that increased viscosity of skim milk concentrates, due to water removal and heat-load, can be explained by increased aggregation of the casein micelles into elongated aggregates and increased smoothening of the casein micelle surface.
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Affiliation(s)
- Morten V Christiansen
- Department of Food Science, University of Copenhagen, Rolighedsvej 26, 1958 Frederiksberg C, Denmark
| | - Gregory N Smith
- ISIS Neutron Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - Erik S Brok
- Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 København Ø, Denmark
| | - Martin Schmiele
- Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 København Ø, Denmark
| | - Lilia Ahrné
- Department of Food Science, University of Copenhagen, Rolighedsvej 26, 1958 Frederiksberg C, Denmark.
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13
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Yang S, Tyler AII, Ahrné L, Kirkensgaard JJK. Skimmed milk structural dynamics during high hydrostatic pressure processing from in situ SAXS. Food Res Int 2021; 147:110527. [PMID: 34399505 DOI: 10.1016/j.foodres.2021.110527] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 05/27/2021] [Accepted: 06/11/2021] [Indexed: 10/21/2022]
Abstract
Understanding the changes in milk at a nanostructural level during high-pressure (HP) treatment can provide new insights to improve the safety and functionality of dairy products. In this study, modifications of milk nanostructure during HP were studied in situ by small-angle X-ray scattering (SAXS). Skimmed milk was pressurized to 200 or 400 MPa at 25, 40 or 60 °C and held for 5 or 10 min, and the effect of single- and double-HP treatment was also investigated. In most cases, the SAXS patterns of skimmed milk are well fitted with a three-population model: a low-q micellar feature reflecting the overall micelle size (~0.002 Å-1), a small casein cluster contribution at intermediate-q (around 0.01 Å-1) and a high-q (0.08-0.1 Å-1) population of milk protein inhomogeneities. However, at 60 °C a scattering feature of colloidal calcium phosphate (CCP) which is normally only seen with neutron scattering, was observed at 0.035 Å-1. By varying the pressure, temperature, holding and depressurization times, as well as performing cycled pressure treatment, we followed the dynamic structural changes in the skimmed milk protein structure at different length scales, which depending on the processing conditions, were irreversible or reversible within the timescales investigated. Pressure and temperature of the HP process have major effects, not only on size of casein micelles, but also on "protein inhomogeneities" within their internal structure. Under HP, increasing processing time at 200 MPa induced re-association of the micelles, however, the changes in the internal structure were more pressure-dependent than time dependent.
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Affiliation(s)
- Shuailing Yang
- Department of Food Science, University of Copenhagen, DK-1958 Frederiksberg C, Denmark
| | - Arwen I I Tyler
- School of Food Science and Nutrition, University of Leeds, LS2 9JT Leeds, United Kingdom
| | - Lilia Ahrné
- Department of Food Science, University of Copenhagen, DK-1958 Frederiksberg C, Denmark.
| | - Jacob J K Kirkensgaard
- Department of Food Science, University of Copenhagen, DK-1958 Frederiksberg C, Denmark; Niels Bohr Institute, University of Copenhagen, DK-2100 København Ø, Denmark.
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14
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The heterogeneous substructure of casein micelles evidenced by SAXS and NMR in demineralized samples. Food Hydrocoll 2021. [DOI: 10.1016/j.foodhyd.2021.106653] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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15
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Bayrak M, Mata J, Raynes JK, Greaves M, White J, Conn CE, Floury J, Logan A. Investigating casein gel structure during gastric digestion using ultra-small and small-angle neutron scattering. J Colloid Interface Sci 2021; 594:561-574. [PMID: 33780761 DOI: 10.1016/j.jcis.2021.03.087] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 02/24/2021] [Accepted: 03/15/2021] [Indexed: 11/25/2022]
Abstract
This study aimed to understand the structural devolution of 10% w/w rennet-induced (RG) and transglutaminase-induced acid (TG) gels in H2O and D2O under in vitro gastric conditions with and without pepsin. The real-time devolution of structure at a nano- (e.g. colloidal calcium phosphate (CCP) and micelle) and micro- (gel network) level was determined using ultra-small (USANS) and small-angle neutron scattering (SANS) with electron microscopy. Results demonstrate that gel firmness or elasticity determines disintegration behaviour during simulated mastication and consequently the particle size entering the stomach. Shear of mixing in the stomach, pH, and enzyme activity will also affect the digestion process. Our results suggest that shear of mixing primarily results in erosion at the particle surface and governs gel disintegration behaviour during the early stages of digestion. Pepsin diffusivity, and hence action, occur more readily in the latter stages of gastric digestion via access to the particle interior. This occurs via the progressively larger pores of the looser gel network and channels created within the larger, less dense casein micelles of the RG gels. Gel firmness and brittleness were greater in the D2O samples compared to H2O, facilitating gel disintegration. Despite the higher strength and elasticity of RG compared to TG, the protein network strands of the RG gels become more compact when exposed to the acidic gastric environment with comparatively larger pores observed through SEM imaging. This led to a higher degree of digestibility in RG gels compared to TG gels. This is the first study to examine casein gel structure during simulated gastric digestion using scattering and highlights the benefits of neutron scattering to monitor structural changes during digestion at multiple length scales.
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Affiliation(s)
- Meltem Bayrak
- CSIRO Agriculture and Food, 671 Sneydes Road, Werribee, Victoria 3030, Australia; School of Science, STEM College, RMIT University, 124 La Trobe Street, Melbourne, VIC 3000, Australia.
| | - Jitendra Mata
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW 2234, Australia.
| | - Jared K Raynes
- CSIRO Agriculture and Food, 671 Sneydes Road, Werribee, Victoria 3030, Australia.
| | - Mark Greaves
- CSIRO Manufacturing, Bayview Avenue, Clayton, VIC 3168, Australia.
| | - Jacinta White
- CSIRO Manufacturing, Bayview Avenue, Clayton, VIC 3168, Australia.
| | - Charlotte E Conn
- School of Science, STEM College, RMIT University, 124 La Trobe Street, Melbourne, VIC 3000, Australia.
| | | | - Amy Logan
- CSIRO Agriculture and Food, 671 Sneydes Road, Werribee, Victoria 3030, Australia.
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16
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Sruthi L, Srivastava V, Schmidt LE, Deshpande AP, Varughese S. Contributions from microstructural changes to the rheological behavior of casein dispersions during drying. SOFT MATTER 2020; 16:10954-10968. [PMID: 33146222 DOI: 10.1039/d0sm00992j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In several applications, a protein such as casein in dispersion form undergoes multiple processing steps including drying. In this work, the rheological and microstructural features of casein dispersions concentrated by evaporation of the solvent (drying dispersions) were studied in comparison with those of equal concentrations of the as-prepared dispersions without drying. The molecular assembly of casein is affected by drying along with the conformational composition changes in the secondary structures such as α-helix, β-sheets, turns and random structures of the protein. Modeling of the rheological data indicates that these changes also affect the packing of casein molecular assemblies and these molecular assemblies in alkaline dispersions can behave as soft deformable particles. During drying, casein dispersions show prominent shear thinning for concentrations higher than 20 wt% along with the prevalence of α-helices and β-sheets. In comparison, the as-prepared dispersions show different microstructural features, and therefore different rheological responses. A detailed analysis shows that alkalinity changes during drying is the crucial factor controlling the microstructural changes of the soft casein particles and hence the rheology.
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Affiliation(s)
- Lalitha Sruthi
- Department of Chemical Engineering, Indian Institute of Technology, Madras, India.
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17
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Singh R, Hemar Y, Gilbert EP, Wu Z, Yang Z. Effect of genipin cross-linking on the structural features of skim milk in the presence of ethylenediaminetetraacetic acid (EDTA). Colloids Surf A Physicochem Eng Asp 2020. [DOI: 10.1016/j.colsurfa.2020.125174] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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18
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Wu S, Li G, Xue Y, Ashokkumar M, Zhao H, Liu D, Zhou P, Sun Y, Hemar Y. Solubilisation of micellar casein powders by high-power ultrasound. ULTRASONICS SONOCHEMISTRY 2020; 67:105131. [PMID: 32339869 DOI: 10.1016/j.ultsonch.2020.105131] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 04/11/2020] [Accepted: 04/13/2020] [Indexed: 06/11/2023]
Abstract
High protein milk ingredients, such as micellar casein powder (MCP), exhibit poor solubility upon reconstitution in water, particularly after long-time storage. In this study, ultrasonication (20 kHz, power density of 0.75 W/ml) was used to improve the solubility of aged MCP powders. For all the MCP powders (concentration varying from 0.5 to 5%, and storage of MCP at 50 °C for up to 10 days) it was found that short time ultrasonication (2.5 min) reduced the size of the protein particles from >30 μm to ∼0.1 μm, as measured by light scattering. This resulted in an improvement of solubility (>95%) for all the MCP powders. Cryo-electron microscopy and small x-ray angle scattering showed that the MCP powders dissolved into particles with morphologies and internal structure similar to native casein micelles in bovine milk. SDS-PAGE and RP-HLPC showed that ultrasonication did not affect the molecular weight of the individual casein molecules. Compared to overhead stirring using a 4-blade stirrer, ultrasonication required less than 10 times the drawn electrical energy density to achieve a particle size 10 times smaller.
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Affiliation(s)
- Sinong Wu
- School of Food Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China
| | - Guantian Li
- School of Chemical Sciences, The University of Auckland, New Zealand
| | - Yu Xue
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan 250353, China
| | | | - Haibo Zhao
- School of Food Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China
| | - Dasong Liu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu Province 214122, China
| | - Peng Zhou
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu Province 214122, China
| | - Yang Sun
- School of Food Science and Technology, and School of Chemical Engineering, Hubei University of Arts and Science, Hubei, Xiangyang 441053, China
| | - Yacine Hemar
- School of Food Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China.
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19
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A novel approach to detect milk adulteration based on the determination of protein content by smartphone-based digital image colorimetry. Food Control 2020. [DOI: 10.1016/j.foodcont.2020.107299] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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20
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Nogueira MH, Ben-Harb S, Schmutz M, Doumert B, Nasser S, Derensy A, Karoui R, Delaplace G, Peixoto PP. Multiscale quantitative characterization of demineralized casein micelles: How the partial excision of nano-clusters leads to the aggregation during rehydration. Food Hydrocoll 2020. [DOI: 10.1016/j.foodhyd.2020.105778] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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21
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Hemar Y, Xu C, Wu S, Ashokkumar M. Size reduction of "reformed casein micelles" by high-power ultrasound and high hydrostatic pressure. ULTRASONICS SONOCHEMISTRY 2020; 63:104929. [PMID: 31945573 DOI: 10.1016/j.ultsonch.2019.104929] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 12/05/2019] [Accepted: 12/13/2019] [Indexed: 06/10/2023]
Abstract
We investigated the effect of ultrasound (US) and high hydrostatic pressure (HHP) on the size of reformed casein micelles (RMCs) obtained by titrating calcium and phosphorous solution into sodium caseinate solutions. Both US and HHP reduced the size of the RMCs. A decrease in size from ~200 nm to ~170 nm when US (20 kHz, 0.46 W/mL) was applied for 30 min; and down to ~85 nm when HHP was applied 500 MPa for 15 min. Electron microscopic analysis showed that the RMCs before and after US are similar to milk native casein micelles, and that HHP extensively disintegrated the RMCs. Small angle X-ray scattering and SDS-PAGE showed that the internal structure of the RMCs as well as the casein molecules are not affected by the US and HHP treatments.
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Affiliation(s)
- Yacine Hemar
- School of Food Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China; The Riddet Institute, Palmerston North, New Zealand.
| | - Cheng Xu
- School of Chemical Sciences. The University of Auckland, New Zealand
| | - Sinong Wu
- School of Food Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
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22
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Lazzaro F, Bouchoux A, Raynes J, Williams R, Ong L, Hanssen E, Lechevalier V, Pezennec S, Cho HJ, Logan A, Gras S, Gaucheron F. Tailoring the structure of casein micelles through a multifactorial approach to manipulate rennet coagulation properties. Food Hydrocoll 2020. [DOI: 10.1016/j.foodhyd.2019.105414] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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23
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Cubides YTP, Eklund PR, Foegeding EA. Casein as a Modifier of Whey Protein Isolate Gel: Sensory Texture and Rheological Properties. J Food Sci 2019; 84:3399-3410. [PMID: 31750948 DOI: 10.1111/1750-3841.14933] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 09/15/2019] [Accepted: 10/10/2019] [Indexed: 01/22/2023]
Abstract
The objective of this study was to determine if casein could be used to adjust the structure of whey protein gels and alter targeted textural properties. Secondarily, we sought to determine if specific structural and mechanical properties were associated with sensory texture terms. Heat set gels were made from whey proteins alone or combined with casein in micellar or dispersed form at pH 6.0 and 5.5. Replacing the whey protein with casein produced a gel breakdown pattern that was more cohesive during mastication with increased moisture retention. Additionally, casein addition reduced gel strength but minimally altered recoverable energy (an indicator of elasticity). Structural breakdown patterns were shifted from brittle- to ductile-like fracture for gels containing dispersed casein at pH 5.5 or micellar casein at pH 6.0. Shifts in microstructure observed by confocal microscopy could not explain the changes in mechanical or sensory textures. The differentiating sensory attributes among treatments were adhesiveness, cohesiveness of mass, tackiness, firmness, fracturability, and deformability. Most notably, adding casein increased cohesiveness while maintaining water holding properties. Sensory texture properties could be explained by a combination of macroscopic structural changes (appearance), fracture properties, and postfracture breakdown pattern. Overall, it was demonstrated that casein can be used to alter whey protein gel structure such that sensory firmness and fracturability are decreased and cohesiveness is increased, while preventing a large increase in moisture release. PRACTICAL APPLICATION: There is a current desire to use alternative sources of protein in a variety of food applications, which requires the ability to design food structures with specific textural properties. Whey protein gels were used as a model soft solid structure with textural attributes of low cohesiveness and water release, and high firmness and fracturability. It was shown that adding casein modified the structure such that cohesiveness increased, firmness and fracturability decreased, and water holding ability was maintained. Using a second source of protein to modify a primary protein network appears to be a viable way to adjust textural properties.
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Affiliation(s)
| | | | - E Allen Foegeding
- Dept. of Food, Bioprocessing and Nutrition Sciences, North Carolina State Univ., Box 7624, Raleigh, NC, 27695-7624
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24
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Wang Y, Eastwood B, Yang Z, de Campo L, Knott R, Prosser C, Carpenter E, Hemar Y. Rheological and structural characterization of acidified skim milks and infant formulae made from cow and goat milk. Food Hydrocoll 2019. [DOI: 10.1016/j.foodhyd.2019.05.020] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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25
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The Effect of Calcium, Citrate, and Urea on the Stability of Ultra-High Temperature Treated Milk: A Full Factorial Designed Study. Foods 2019; 8:foods8090418. [PMID: 31533213 PMCID: PMC6770255 DOI: 10.3390/foods8090418] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 09/10/2019] [Accepted: 09/12/2019] [Indexed: 11/23/2022] Open
Abstract
The composition of raw milk is important for the stability of dairy products with a long shelf-life. Based on known historical changes in raw milk composition, the aim of this study was to get a better understanding of how possible future variations in milk composition may affect the stability of dairy products. The effects of elevated calcium, citrate, and urea levels on the stability of ultra-high temperature (UHT) treated milk stored for 52 weeks at 4, 20, 30, and 37 °C were investigated by a two-level full factorial designed study with fat separation, fat adhesion, sedimentation, color, pH, ethanol stability, and heat coagulation time as response variables. The results showed that elevated level of calcium lowered the pH, resulting in sedimentation and significantly decreased stability. Elevated level of citrate was associated with color, but the stability was not improved compared to the reference UHT milk. Elevated levels of urea or interaction terms had little effect on the stability of UHT milk. Storage conditions significantly affected the stability. In conclusion, to continue produce dairy products with high stability, the dairy industry should make sure the calcium content of raw milk is not too high and that storage of the final product is appropriate.
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26
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Karlsson MA, Langton M, Innings F, Malmgren B, Höjer A, Wikström M, Lundh Å. Changes in stability and shelf-life of ultra-high temperature treated milk during long term storage at different temperatures. Heliyon 2019; 5:e02431. [PMID: 31538115 PMCID: PMC6745408 DOI: 10.1016/j.heliyon.2019.e02431] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Revised: 05/01/2019] [Accepted: 09/03/2019] [Indexed: 11/22/2022] Open
Abstract
In the ultra-high temperature (UHT) process, milk is subject to temperatures above 135 °C for few seconds giving a product with a shelf-life of several months. The raw milk quality, UHT process and storage conditions affect the stability. In this study, the stability of UHT milk produced in an indirect system was evaluated by studying changes in taste, colour, fat separation, fat adhesion to the package, sedimentation, gelation, heat coagulation time, pH and ethanol stability during storage for up to one year at different temperatures. UHT milk stored at 4 and 20 °C had the longest shelf-life of 34-36 weeks, limited by sediment formation. Storage at 30 and 37 °C considerably decreased the shelf-life of UHT milk to 16-20 weeks, whereby changes in sediment formation, taste and colour were the limiting factors. Our results suggest that the changes observed at the different storage temperatures can be explained by different known mechanisms.
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Affiliation(s)
- Maria A. Karlsson
- Swedish University of Agricultural Sciences, Department of Molecular Sciences, P.O. 7015, 75007, Uppsala, Sweden
| | - Maud Langton
- Swedish University of Agricultural Sciences, Department of Molecular Sciences, P.O. 7015, 75007, Uppsala, Sweden
| | - Fredrik Innings
- Tetra Pak Processing Systems AB, Ruben Rausings gata, 22186, Lund, Sweden
| | - Bozena Malmgren
- Tetra Pak Processing Systems AB, Ruben Rausings gata, 22186, Lund, Sweden
| | - Annika Höjer
- Norrmejerier Ek. Förening, Mejerivägen 2, 90622, Umeå, Sweden
| | - Malin Wikström
- Norrmejerier Ek. Förening, Mejerivägen 2, 90622, Umeå, Sweden
| | - Åse Lundh
- Swedish University of Agricultural Sciences, Department of Molecular Sciences, P.O. 7015, 75007, Uppsala, Sweden
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27
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28
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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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29
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Rheological and structural properties of coagulated milks reconstituted in D2O: Comparison between rennet and a tamarillo enzyme (tamarillin). Food Hydrocoll 2018. [DOI: 10.1016/j.foodhyd.2017.12.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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30
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Ingham B, Smialowska A, Kirby NM, Wang C, Carr AJ. A structural comparison of casein micelles in cow, goat and sheep milk using X-ray scattering. SOFT MATTER 2018; 14:3336-3343. [PMID: 29658047 DOI: 10.1039/c8sm00458g] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The casein micelle is a flexible construct, with its key structural components being casein proteins and colloidal calcium phosphate nanoclusters. According to literature, milk from different species exhibits differences in composition and physicochemical properties. X-ray scattering techniques were used to investigate and compare the nanoscale structure of casein micelles present in cow, goat and sheep milk. Although there were differences in the size and density of larger scale protein structures, at an atomic level the protein structures were similar. There were also strong similarities in the structure of the calcium-containing nanoclusters, namely that they had similar sizes and separations within the casein micelle for all three species.
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Affiliation(s)
- B Ingham
- Callaghan Innovation, P.O. Box 31310, Lower Hutt 5040, New Zealand.
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31
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In situ study of skim milk structure changes under high hydrostatic pressure using synchrotron SAXS. Food Hydrocoll 2018. [DOI: 10.1016/j.foodhyd.2017.11.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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32
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Specific effect of calcium ions on thermal gelation of aqueous micellar casein suspensions. Colloids Surf B Biointerfaces 2018; 163:218-224. [DOI: 10.1016/j.colsurfb.2017.12.029] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 12/13/2017] [Accepted: 12/15/2017] [Indexed: 11/19/2022]
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33
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Hussain E, Hu Z, Zhou H, He C, Shahzad SA, Yu C. Benzo[ghi]perylene and coronene: ratiometric fluorescent probes for the sensing of microenvironment changes and micelle formation in aqueous medium. NEW J CHEM 2018. [DOI: 10.1039/c8nj00739j] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Benzo[ghi]perylene and coronene were used as ratiometric fluorescent probes to monitor microenvironment changes and monomer–micelle transition for the first time.
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Affiliation(s)
- Ejaz Hussain
- State Key Laboratory of Electroanalytical Chemistry
- Changchun Institute of Applied Chemistry
- Chinese Academy of Sciences
- Changchun
- P. R. China
| | - Zhenzhen Hu
- State Key Laboratory of Electroanalytical Chemistry
- Changchun Institute of Applied Chemistry
- Chinese Academy of Sciences
- Changchun
- P. R. China
| | - Huipeng Zhou
- State Key Laboratory of Electroanalytical Chemistry
- Changchun Institute of Applied Chemistry
- Chinese Academy of Sciences
- Changchun
- P. R. China
| | - Chunhua He
- State Key Laboratory of Electroanalytical Chemistry
- Changchun Institute of Applied Chemistry
- Chinese Academy of Sciences
- Changchun
- P. R. China
| | - Sohail Anjum Shahzad
- State Key Laboratory of Electroanalytical Chemistry
- Changchun Institute of Applied Chemistry
- Chinese Academy of Sciences
- Changchun
- P. R. China
| | - Cong Yu
- State Key Laboratory of Electroanalytical Chemistry
- Changchun Institute of Applied Chemistry
- Chinese Academy of Sciences
- Changchun
- P. R. China
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