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Zhang B, Jiang R, Dong K, Li J, Zhang Y, Ghorani B, Emadzadeh B, Nishinari K, Yang N. Controlling Solvent Polarity to Regulate Protein Self-Assembly Morphology and Its Universal Insight for Fibrillation Mechanism. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:7733-7746. [PMID: 38538620 DOI: 10.1021/acs.langmuir.4c00438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/10/2024]
Abstract
The mechanism of ethanol-induced fibrillation of β-lactoglobulin (β-lg) in the acidic aqueous solution upon heating was investigated using various techniques, mainly thioflavin T fluorescence, atomic force microscopy, nonreducing electrophoresis, mass spectrometry, Fourier transform infrared spectroscopy, and circular dichroism spectroscopy. The results showed that fibrillation occurred with a heating time increase, but high ethanol content slowed down the process. At a low ethanol volume fraction, peptides existed after heating for 2 h, with long and straight fibrils formed after 4-6 h, while at a high ethanol volume fraction, the proteins aggregated with very few peptides appeared at the early stage of heating, and short and curved fibrils formed after heating for 8 h. Ethanol weakened the hydrophobic interactions between proteins in the aqueous solution; therefore the latter could not completely balance the electrostatic repulsion, and thus suppressing the fibrillation process. It is believed that the fibrillation of β-lg in the acidic solution upon heating is mainly dominated by the polypeptide model; however, ethanol inhibited the hydrolysis of proteins, and the self-assembly mechanism changed to the monomer model.
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Affiliation(s)
- Bao Zhang
- Glyn O. Phillips Hydrocolloid Research Centre, National "111″ Center for Cellular Regulation and Molecular Pharmaceutics, Key Laboratory of Fermentation Engineering of Ministry of Education, Key Laboratory of Industrial Microbiology in Hubei Province, Department of Bioengineering and Food Science, Hubei University of Technology, Wuhan 430068, China
| | - Ruisheng Jiang
- Glyn O. Phillips Hydrocolloid Research Centre, National "111″ Center for Cellular Regulation and Molecular Pharmaceutics, Key Laboratory of Fermentation Engineering of Ministry of Education, Key Laboratory of Industrial Microbiology in Hubei Province, Department of Bioengineering and Food Science, Hubei University of Technology, Wuhan 430068, China
| | - Kexin Dong
- Glyn O. Phillips Hydrocolloid Research Centre, National "111″ Center for Cellular Regulation and Molecular Pharmaceutics, Key Laboratory of Fermentation Engineering of Ministry of Education, Key Laboratory of Industrial Microbiology in Hubei Province, Department of Bioengineering and Food Science, Hubei University of Technology, Wuhan 430068, China
| | - Jing Li
- Glyn O. Phillips Hydrocolloid Research Centre, National "111″ Center for Cellular Regulation and Molecular Pharmaceutics, Key Laboratory of Fermentation Engineering of Ministry of Education, Key Laboratory of Industrial Microbiology in Hubei Province, Department of Bioengineering and Food Science, Hubei University of Technology, Wuhan 430068, China
| | - Yan Zhang
- Glyn O. Phillips Hydrocolloid Research Centre, National "111″ Center for Cellular Regulation and Molecular Pharmaceutics, Key Laboratory of Fermentation Engineering of Ministry of Education, Key Laboratory of Industrial Microbiology in Hubei Province, Department of Bioengineering and Food Science, Hubei University of Technology, Wuhan 430068, China
- Food Hydrocolloid International Science and Technology Cooperation Base of Hubei Province, Hubei University of Technology, Wuhan 430068, China
| | - Behrouz Ghorani
- Department of Food Nanotechnology, Research Institute of Food Science & Technology (RIFST), Mashhad 91895-157-356, Iran
| | - Bahareh Emadzadeh
- Department of Food Nanotechnology, Research Institute of Food Science & Technology (RIFST), Mashhad 91895-157-356, Iran
| | - Katsuyoshi Nishinari
- Glyn O. Phillips Hydrocolloid Research Centre, National "111″ Center for Cellular Regulation and Molecular Pharmaceutics, Key Laboratory of Fermentation Engineering of Ministry of Education, Key Laboratory of Industrial Microbiology in Hubei Province, Department of Bioengineering and Food Science, Hubei University of Technology, Wuhan 430068, China
- Food Hydrocolloid International Science and Technology Cooperation Base of Hubei Province, Hubei University of Technology, Wuhan 430068, China
| | - Nan Yang
- Glyn O. Phillips Hydrocolloid Research Centre, National "111″ Center for Cellular Regulation and Molecular Pharmaceutics, Key Laboratory of Fermentation Engineering of Ministry of Education, Key Laboratory of Industrial Microbiology in Hubei Province, Department of Bioengineering and Food Science, Hubei University of Technology, Wuhan 430068, China
- Food Hydrocolloid International Science and Technology Cooperation Base of Hubei Province, Hubei University of Technology, Wuhan 430068, China
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2
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Gochev GG, Schneck E, Miller R. Effects of Aqueous Isotopic Substitution on the Adsorption Dynamics and Dilational Rheology of β-Lactoglobulin Layers at the Water/Air Interface. J Phys Chem B 2024; 128:2821-2830. [PMID: 38471121 PMCID: PMC10961727 DOI: 10.1021/acs.jpcb.3c08417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 02/26/2024] [Accepted: 02/29/2024] [Indexed: 03/14/2024]
Abstract
The effect of the degree of isotopic substitution of the aqueous medium on the adsorption kinetics and the surface dilational rheological behavior at the water/air interface of the globular protein β-lactoglobulin was investigated. Aqueous solutions with fixed concentrations of 1 μM protein and 10 mM hydrogenous buffer with controlled pH 7 were prepared in H2O, D2O, and an isotopic mixture of 8.1% v/v D2O in H2O (called air contrast matched water, ACMW). Using a bubble shape analysis tensiometer, we obtained various experimental dependencies of the dilational viscoelasticity modulus E as a function of the dynamic surface pressure and of the frequency and amplitude of bubble surface area oscillations, either in the course of adsorption or after having reached a steady state. In general, the results revealed virtually no effect from substituting H2O by ACMW but distinct albeit relatively weak effects for intermediate adsorption times for D2O as the aqueous phase. In the final stage of adsorption, established after around 10 h, the equilibrium adsorption and the dilational rheological behavior of all protein layers under investigation are only very weakly affected by the presence of D2O. The obtained results help to design experimental protocols for protein adsorption studies, for example, by neutron reflectivity.
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Affiliation(s)
- Georgi G. Gochev
- Jerzy
Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, 30239 Krakow, Poland
- Institute
of Physical Chemistry, Bulgarian Academy
of Sciences, 1113 Sofia, Bulgaria
| | - Emanuel Schneck
- TU Darmstadt, Institute for Condensed Matter Physics, 64289 Darmstadt, Germany
| | - Reinhard Miller
- TU Darmstadt, Institute for Condensed Matter Physics, 64289 Darmstadt, Germany
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3
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Giacomin CE, Chen RY, Hack E, Fischer P. Tea film formation in artificial tap water. SOFT MATTER 2023; 19:5967-5977. [PMID: 37491884 PMCID: PMC10411494 DOI: 10.1039/d3sm00169e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 07/19/2023] [Indexed: 07/27/2023]
Abstract
On the surface of tea infusions, the formation of a transparent, shiny film which cracks upon disturbance can often be observed. This study aims to determine how water composition, tea varieties, and tea additives impact the formation and properties of tea film, often also called tea scum. The strength of the surface film, composed of polyphenols complexed with various ions from tap water, was investigated by interfacial rheology. Microscopy and ellipsometry were used to investigate structure and thickness of the adsorption layer, respectively. We find that green tea forms more visible layers than black tea in soft and moderate artificial tap water, but in these same waters, black tea demonstrated greater surface strength. In hard artificial tap water, green tea demonstrated greater surface strength than black. No visible layer nor surface strengthening was observed on rooibos tea. Brews in hard artificial tap water formed brittle films for green tea, fracturing at strains one order of magnitude lower than in soft or moderate. Despite large variations in film strength, black tea at all water hardness levels tested formed a film with 20 nm thickness. In black tea an increased resilience to deformation was found when adding β-casein, a protein found in milk.
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Affiliation(s)
- Caroline E Giacomin
- ETH Zürich, Institute of Food Nutrition and Health, Schmelzbergstrasse 7, 8092 Zürich, Switzerland.
| | - Rebecca Yun Chen
- ETH Zürich, Institute of Food Nutrition and Health, Schmelzbergstrasse 7, 8092 Zürich, Switzerland.
| | - Erwin Hack
- EMPA, Transport at Nanoscale Interfaces, Überlandstrasse 129, 8600 Dübendorf, Switzerland
| | - Peter Fischer
- ETH Zürich, Institute of Food Nutrition and Health, Schmelzbergstrasse 7, 8092 Zürich, Switzerland.
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4
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Kummer N, Giacomin CE, Fischer P, Campioni S, Nyström G. Amyloid fibril-nanocellulose interactions and self-assembly. J Colloid Interface Sci 2023; 641:338-347. [PMID: 36934581 DOI: 10.1016/j.jcis.2023.03.002] [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: 12/21/2022] [Revised: 02/20/2023] [Accepted: 03/01/2023] [Indexed: 03/07/2023]
Abstract
Amyloid fibrils from inexpensive food proteins and nanocellulose are renewable and biodegradable materials with broad ranging applications, such as water purification, bioplastics and biomaterials. To improve the mechanical properties of hybrid amyloid-nanocellulose materials, their colloidal interactions need to be understood and tuned. A combination of turbidity and zeta potential measurements, rheology and atomic force microscopy point to the importance of electrostatic interactions. These interactions lead to entropy-driven polyelectrolyte complexation for positively charged hen egg white lysozyme (HEWL) amyloids with negatively charged nanocellulose. The complexation increased the elasticity of the amyloid network by cross-linking individual fibrils. Scaling laws suggest different contributions to elasticity depending on nanocellulose morphology: cellulose nanocrystals induce amyloid bundling and network formation, while cellulose nanofibrils contribute to a second network. The contribution of the amyloids to the elasticity of the entire network structure is independent of nanocellulose morphology and agrees with theoretical scaling laws. Finally, strong and almost transparent hybrid amyloid-nanocellulose gels were prepared in a slow self-assembly started from repulsive co-dispersions above the isoelectric point of the amyloids, followed by dialysis to decrease the pH and induce amyloid-nanocellulose attraction and cross-linking. In summary, the gained knowledge on colloidal interactions provides an important basis for the design of functional biohybrid materials based on these two biopolymers.
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Affiliation(s)
- Nico Kummer
- Laboratory for Cellulose & Wood Materials, Empa - Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland; Institute of Food Nutrition and Health, Schmelzbergstrasse 9, ETH Zurich, 8092 Zurich, Switzerland.
| | - Caroline E Giacomin
- Institute of Food Nutrition and Health, Schmelzbergstrasse 9, ETH Zurich, 8092 Zurich, Switzerland.
| | - Peter Fischer
- Institute of Food Nutrition and Health, Schmelzbergstrasse 9, ETH Zurich, 8092 Zurich, Switzerland.
| | - Silvia Campioni
- Laboratory for Cellulose & Wood Materials, Empa - Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland.
| | - Gustav Nyström
- Laboratory for Cellulose & Wood Materials, Empa - Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland; Institute of Food Nutrition and Health, Schmelzbergstrasse 9, ETH Zurich, 8092 Zurich, Switzerland.
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5
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Kitamura S, Yoshioka T, Nakagawa K, Kitagawa T, Okamoto Y, Matsuoka A, Kamio E, Matsuyama H. Organic solvent reverse osmosis characteristics of TiO2-ZrO2-organic chelating ligand (OCL) composite membranes using OCLs with different molecular sizes. Sep Purif Technol 2023. [DOI: 10.1016/j.seppur.2023.123576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/13/2023]
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6
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Separation Technologies for Whey Protein Fractionation. FOOD ENGINEERING REVIEWS 2023. [DOI: 10.1007/s12393-022-09330-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Abstract
Whey is a by-product of cheese, casein, and yogurt manufacture. It contains a mixture of proteins that need to be isolated and purified to fully exploit their nutritional and functional characteristics. Protein-enriched fractions and highly purified proteins derived from whey have led to the production of valuable ingredients for many important food and pharmaceutical applications. This article provides a review on the separation principles behind both the commercial and emerging techniques used for whey protein fractionation, as well as the efficacy and limitations of these techniques in isolating and purifying individual whey proteins. The fractionation of whey proteins has mainly been achieved at commercial scale using membrane filtration, resin-based chromatography, and the integration of multiple technologies (e.g., precipitation, membrane filtration, and chromatography). Electromembrane separation and membrane chromatography are two main emerging techniques that have been developed substantially in recent years. Other new techniques such as aqueous two-phase separation and magnetic fishing are also discussed, but only a limited number of studies have reported their application in whey protein fractionation. This review offers useful insights into research directions and technology screening for academic researchers and dairy processors for the production of whey protein fractions with desired nutritional and functional properties.
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7
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Paladii IV, Vrabie EG, Sprinchan KG, Bologa MK. Whey: Review. Part 2. Treatment Processes and Methods. SURFACE ENGINEERING AND APPLIED ELECTROCHEMISTRY 2021. [DOI: 10.3103/s1068375521060119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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8
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Abstract
The significance of dairy in human health and nutrition is gaining significant momentum as consumers continue to desire wholesome, nutritious foods to fulfill their health and wellness needs. Bovine milk not only consists of all the essential nutrients required for growth and development, it also provides a broad range of bioactive components that play an important role in managing human homeostasis and immune function. In recent years, milk bioactives, including α-lactalbumin, lactoferrin, glycomacropeptide, milk fat globule membrane, and milk oligosaccharides, have been intensively studied because of their unique bioactivity and functionality. Challenges for the application of these bioactive components in food and pharmaceutical formulations are associated with their isolation and purification on an industrial scale and also with their physical and chemical instability during processing, storage, and digestion. These challenges can be overcome by advanced separation techniques and sophisticated nano- or micro-encapsulation technologies. Current knowledge about the chemistry, separation, and encapsulation technology of major bioactives derived from bovine milk and their application in the food industry is reviewed here.
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Affiliation(s)
- Tiantian Lin
- Department of Food Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York, USA
| | - Gopinathan Meletharayil
- Gopinathan Meletharayil and Rohit Kapoor are with the National Dairy Council, Rosemont, Illinois, USA
| | - Rohit Kapoor
- Gopinathan Meletharayil and Rohit Kapoor are with the National Dairy Council, Rosemont, Illinois, USA
| | - Alireza Abbaspourrad
- Department of Food Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York, USA
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9
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Reig M, Vecino X, Cortina JL. Use of Membrane Technologies in Dairy Industry: An Overview. Foods 2021; 10:foods10112768. [PMID: 34829049 PMCID: PMC8620702 DOI: 10.3390/foods10112768] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 10/26/2021] [Accepted: 11/08/2021] [Indexed: 01/11/2023] Open
Abstract
The use of treatments of segregated process streams as a water source, as well as technical fluid reuse as a source of value-added recovery products, is an emerging direction of resource recovery in several applications. Apart from the desired final product obtained in agro-food industries, one of the challenges is the recovery or separation of intermediate and/or secondary metabolites with high-added-value compounds (e.g., whey protein). In this way, processes based on membranes, such as microfiltration (MF), ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO), could be integrated to treat these agro-industrial streams, such as milk and cheese whey. Therefore, the industrial application of membrane technologies in some processing stages could be a solution, replacing traditional processes or adding them into existing treatments. Therefore, greater efficiency, yield enhancement, energy or capital expenditure reduction or even an increase in sustainability by producing less waste, as well as by-product recovery and valorization opportunities, could be possible, in line with industrial symbiosis and circular economy principles. The maturity of membrane technologies in the dairy industry was analyzed for the possible integration options of membrane processes in their filtration treatment. The reported studies and developments showed a wide window of possible applications for membrane technologies in dairy industry treatments. Therefore, the integration of membrane processes into traditional processing schemes is presented in this work. Overall, it could be highlighted that membrane providers and agro-industries will continue with a gradual implementation of membrane technology integration in the production processes, referring to the progress reported on both the scientific literature and industrial solutions commercialized.
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Affiliation(s)
- Mònica Reig
- Barcelona Research Center for Multiscale Science and Engineering, Campus Diagonal-Besòs, 08930 Barcelona, Spain; (X.V.); (J.L.C.)
- Chemical Engineering Department, Escola d’Enginyeria de Barcelona Est (EEBE), Campus Diagonal-Besòs, Universitat Politècnica de Catalunya (UPC)-BarcelonaTECH, C/Eduard Maristany 10-14, 08930 Barcelona, Spain
- Correspondence: ; Tel.: +34-93-4016184
| | - Xanel Vecino
- Barcelona Research Center for Multiscale Science and Engineering, Campus Diagonal-Besòs, 08930 Barcelona, Spain; (X.V.); (J.L.C.)
- Chemical Engineering Department, Escola d’Enginyeria de Barcelona Est (EEBE), Campus Diagonal-Besòs, Universitat Politècnica de Catalunya (UPC)-BarcelonaTECH, C/Eduard Maristany 10-14, 08930 Barcelona, Spain
| | - José Luis Cortina
- Barcelona Research Center for Multiscale Science and Engineering, Campus Diagonal-Besòs, 08930 Barcelona, Spain; (X.V.); (J.L.C.)
- Chemical Engineering Department, Escola d’Enginyeria de Barcelona Est (EEBE), Campus Diagonal-Besòs, Universitat Politècnica de Catalunya (UPC)-BarcelonaTECH, C/Eduard Maristany 10-14, 08930 Barcelona, Spain
- CETaqua, Carretera d’Esplugues, 75, 08940 Cornellà de Llobregat, Spain
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10
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Ramamirtham S, Whitby CP, Zare D, Weeks M, Williams MA. The rheological properties of bovine β-Lactoglobulin stabilized oil/water interfaces depend on the protein's quaternary structure. Food Hydrocoll 2021. [DOI: 10.1016/j.foodhyd.2021.106834] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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11
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Ramamirtham S, Williams MAK, Zare D, Weeks M, Whitby CP. Complexes of β-lactoglobulin and high methyl-esterified pectin as a one-shot delivery system for reinforcing oil/water interfaces. SOFT MATTER 2021; 17:8517-8522. [PMID: 34494060 DOI: 10.1039/d1sm00989c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Electrostatic complexation of negatively charged polysaccharides with β-lactoglobulin (β-lg) has been shown to bolster the protein films at oil/water interfaces thereby improving emulsion stability. However, recent sub-phase exchange experiments demonstrated that highly charged polysaccharides such as low methyl-esterified pectin are complementary only if sequentially introduced to a pre-formed interfacial β-lg film. In this study, results of transient interfacial shear rheology show that, by using high-methylesterified pectins instead, complexes can be formed in pre-mixed solutions with β-lg at pH 4 that can lead to reinforced protein films at dodecane/water interfaces. Using this one-shot adsorption of such complexes, pectins as well as short chain polysaccharides like homogalacturonan nearly doubled the steady state shear elastic moduli as compared to that of a pure β-lg film. The lag times of film formation were established to be primarily decided by the charge density and pattern on the polysaccharide. Based on the results from mixed solutions of β-lg monomers, it is proposed that the polysaccharide at pH 4 strengthens the resulting interfacial layer by concatenating adsorbed β-lg molecules thereby establishing cross-links in the aqueous phase.
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Affiliation(s)
- Sashikumar Ramamirtham
- School of Fundamental Science, Massey University, Palmerston North, 4442, New Zealand.
- The Macdiarmid Institute for Advanced Materials and Nanotechnology, Wellington, 6140, New Zealand
| | - Martin A K Williams
- School of Fundamental Science, Massey University, Palmerston North, 4442, New Zealand.
- The Macdiarmid Institute for Advanced Materials and Nanotechnology, Wellington, 6140, New Zealand
- Riddet Institute, Palmerston North, New Zealand
| | - Davoud Zare
- Fonterra Research and Development Center, Palmerston North, 4472, New Zealand
| | - Mike Weeks
- Smart Foods Innovation Centre, AgResearch, Palmerston North, 4442, New Zealand
| | - Catherine P Whitby
- School of Fundamental Science, Massey University, Palmerston North, 4442, New Zealand.
- The Macdiarmid Institute for Advanced Materials and Nanotechnology, Wellington, 6140, New Zealand
- Riddet Institute, Palmerston North, New Zealand
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12
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Haller N, Maier I, Kulozik U. Molecular Analytical Assessment of Thermally Precipitated α-Lactalbumin after Resolubilization. Foods 2021; 10:foods10092231. [PMID: 34574341 PMCID: PMC8465387 DOI: 10.3390/foods10092231] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 09/12/2021] [Accepted: 09/15/2021] [Indexed: 11/24/2022] Open
Abstract
Selective thermal precipitation followed by a mechanical separation step is a well described method for fractionation of the main whey proteins, α-lactalbumin (α-la) and β-lactoglobulin (β-lg). By choosing appropriate environmental conditions the thermal precipitation of either α-la or β-lg can be induced. Whereas β-lg irreversibly aggregates, the precipitated α-la can be resolubilized by a subsequent adjustment of the solution’s pH and the ionic composition. This study reports on the analytical characterization of resolubilized α-la compared to its native counterpart as a reference in order to assess whether the resolubilized α-la can be considered close to ‘native’. Turbidity and quantification by RP-HPLC of the resolubilized α-la solutions were used as a measure of solubility in aqueous environment. RP-HPLC was also applied to determine the elution time as a measure for protein’s hydrophobicity. DSC measurement was performed to determine the denaturation peak temperature of resolubilized α-la. FTIR spectroscopy provided insights in the secondary structure. The refolding of α-la achieved best results using pH 8.0 and a 3-fold stoichiometric amount of Ca2+ per α-la molecule. The results showed that the mechanism of aggregation induced by gentle thermal treatment under acidic conditions with subsequent mechanical separation is reversible to a certain extent, however, the exact native conformation was not restored.
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13
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Hu B, Hu J, Han L, Cao J, Nishinari K, Yang J, Fang Y, Li D. Conformational transition and gelation of κ-carrageenan in electrostatic complexation with β-lactoglobulin aggregates. Food Hydrocoll 2021. [DOI: 10.1016/j.foodhyd.2021.106764] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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14
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Kubbutat P, Leitão L, Kulozik U. Stability of Foams in Vacuum Drying Processes. Effects of Interactions between Sugars, Proteins, and Surfactants on Foam Stability and Dried Foam Properties. Foods 2021; 10:foods10081876. [PMID: 34441652 PMCID: PMC8392398 DOI: 10.3390/foods10081876] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 08/05/2021] [Accepted: 08/11/2021] [Indexed: 01/16/2023] Open
Abstract
The hypothesis was that saccharides mediate interactions between surface-active components and that this will have an impact on foam decay during the drying process. Static light scattering was performed to determine changes in interactions between the foam stabilizer on a molecular level. Furthermore, pendant drop and oscillating drop measurements were performed to examine the surface tension and surface rheology. Foams were dried in conventional dryers as well as microwave-supported vacuum dryers. Final foam properties were determined. It was shown that the addition of sugars, often added as protective substances for sensitive organic molecules, resulted in lower repulsion between different types of surface-active components, namely polysorbate 80 and β-lactoglobulin (β-lg). Differences in impact of the types of sugars and between different types of surfactant, protein, and small molecules were observed influencing the foam decay behavior. The interfacial properties of polysorbate 80 and β-lg were influenced by the type of the used sugars. The surface elasticity of protein stabilized surfaces was higher compared to that of polysorbate stabilized systems. Protein stabilized systems remained more stable compared to polysorbate systems, which was also affected by the used saccharide. Overall, a correlation between molecular interactions and foam decay behavior was found.
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15
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Correlation between Physico-Chemical Characteristics of Particulated β-Lactoglobulin and Its Behavior at Air/Water and Oil/Water Interfaces. Foods 2021; 10:foods10061426. [PMID: 34205453 PMCID: PMC8234016 DOI: 10.3390/foods10061426] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 06/14/2021] [Accepted: 06/16/2021] [Indexed: 11/17/2022] Open
Abstract
It is widely accepted that protein-based particles can efficiently stabilize foams and emulsions. However, it is not fully elucidated which particle properties are decisive for the stabilization of air/water and oil/water interfaces. To unravel this correlation, selected properties of nano-sized soluble β-lactoglobulin particles were changed one at a time. Therefore, particles of (1) variable size but similar zeta potential and degree of cross-linking and (2) similar size but different further properties were produced by heat treatment under a specific combination of pH value and NaCl concentration and then analyzed for their interfacial behavior as well as foaming and emulsifying properties. On the one hand, it was found that the initial phase of protein adsorption at both the air/water and the oil/water interface was mainly influenced by the zeta potential, independent of the particle size. On the other hand, foam stability as resolved from the time-dependent evolution of mean bubble area negatively correlated with disulfide cross-linking, whereas emulsion stability in terms of oil droplet flocculation showed a positive correlation with disulfide cross-linking. In addition, flocculation was more pronounced for larger particles. Concluding from this, foam and emulsion stability are not linked to the same particle properties and, thus, explanatory approaches cannot be used interchangeably.
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16
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Effect of Pre-Heating Prior to Low Temperature 0.1 µm-Microfiltration of Milk on Casein-Whey Protein Fractionation. Foods 2021; 10:foods10051090. [PMID: 34068990 PMCID: PMC8156618 DOI: 10.3390/foods10051090] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/10/2021] [Accepted: 05/12/2021] [Indexed: 11/16/2022] Open
Abstract
During skim milk microfiltration (nominal pore size of 0.1 µm) at 10 °C, the whey protein purity in the permeate is reduced by an enhanced serum casein permeation, primarily of β-casein. To decrease casein permeation, the possibility of a pre-heating step under pasteurization conditions before the filtration step was investigated, so as to shift the equilibrium from soluble serum casein monomers to impermeable micellar casein. Immediately after the pre-heating step, low temperature microfiltration at 10 °C was conducted before the casein monomers could diffuse into the serum. The hypothesis was that the dissociation of β-casein into the serum as a result of a decreasing temperature takes more time than the duration of the microfiltration process. It was found that pre-heating reduced the β-casein permeation during microfiltration without significantly affecting the flux and whey protein permeation, compared with a microfiltration at 10 °C without the pre-heating step. Furthermore, the addition of calcium (5 and 10 mM) not only reduced the casein permeation and thus increased the permeate purity, defined as a high whey protein-to-casein (g L-1/g L-1) ratio, but also decreased the filtration performance, possibly due to the structural alteration of the deposited casein micelle layer, rendering the deposit more compact and more retentive. Therefore, the possible combination of the addition of calcium and pre-heating prior to microfiltration was also investigated in order to evidence the potential increase of whey protein (WP) purity in the permeate in the case of Ca2+ addition prior to microfiltration. This study shows that pre-heating very close to low temperature microfiltration results in an increased purity of the whey protein fraction obtained in the permeate.
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Pires AF, Marnotes NG, Rubio OD, Garcia AC, Pereira CD. Dairy By-Products: A Review on the Valorization of Whey and Second Cheese Whey. Foods 2021; 10:foods10051067. [PMID: 34066033 PMCID: PMC8151190 DOI: 10.3390/foods10051067] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Revised: 05/02/2021] [Accepted: 05/10/2021] [Indexed: 12/02/2022] Open
Abstract
The search for new food products that promote consumers health has always been of great interest. The dairy industry is perhaps the best example regarding the emergence of new products with claimed health benefits. Cheese whey (CW), the by-product resulting from cheese production, and second cheese whey (SCW), which is the by-product of whey cheese manufacture, have proven to contain potential ingredients for the development of food products with improved nutritional characteristics and other functionalities. Nowadays, due to their nutritional quality, whey products have gained a prominent position among healthy food products. However, for a long time, CW and SCW were usually treated as waste or as animal feed. Due to their high organic content, these by-products can cause serious environmental problems if discarded without appropriate treatment. Small and medium size dairy companies do not have the equipment and structure to process whey and second cheese whey. In these cases, generally, they are used for animal feed or discarded without an appropriate treatment, being the cause of several constraints. There are several studies regarding CW valorization and there is a wide range of whey products in the market. However, in the case of SCW, there remains a lack of studies regarding its nutritional and functional properties, as well as ways to reuse this by-product in order to create economic value and reduce environmental impacts associated to its disposal.
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Affiliation(s)
- Arona Figueroa Pires
- Polytechnic Institute of Coimbra, College of Agriculture, Bencanta, 3045-601 Coimbra, Portugal; (A.F.P.); (N.G.M.)
| | - Natalí Garcia Marnotes
- Polytechnic Institute of Coimbra, College of Agriculture, Bencanta, 3045-601 Coimbra, Portugal; (A.F.P.); (N.G.M.)
- Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Sciences of Lugo, Food Technology Area, University of Santiago de Compostela, E-27002 Lugo, Spain; (O.D.R.); (A.C.G.)
| | - Olga Díaz Rubio
- Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Sciences of Lugo, Food Technology Area, University of Santiago de Compostela, E-27002 Lugo, Spain; (O.D.R.); (A.C.G.)
| | - Angel Cobos Garcia
- Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Sciences of Lugo, Food Technology Area, University of Santiago de Compostela, E-27002 Lugo, Spain; (O.D.R.); (A.C.G.)
| | - Carlos Dias Pereira
- Polytechnic Institute of Coimbra, College of Agriculture, Bencanta, 3045-601 Coimbra, Portugal; (A.F.P.); (N.G.M.)
- Research Centre for Natural Resources, Environment and Society (CERNAS), Bencanta, 3045-601 Coimbra, Portugal
- Correspondence:
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Touhami S, Chamberland J, Perreault V, Suwal S, Marciniak A, Pouliot Y, Doyen A. Coupling high hydrostatic pressure and ultrafiltration for fractionation of alpha-lactalbumin from skim milk. SEP SCI TECHNOL 2021. [DOI: 10.1080/01496395.2020.1749079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Serine Touhami
- Department of Food Sciences, Institute of Nutrition and Functional Foods (INAF), Dairy Research Centre (STELA), Université Laval, Quebec City, Quebec, Canada
| | - Julien Chamberland
- Department of Food Sciences, Institute of Nutrition and Functional Foods (INAF), Dairy Research Centre (STELA), Université Laval, Quebec City, Quebec, Canada
| | - Véronique Perreault
- Department of Food Sciences, Institute of Nutrition and Functional Foods (INAF), Dairy Research Centre (STELA), Université Laval, Quebec City, Quebec, Canada
| | - Shyam Suwal
- Department of Food Sciences, Institute of Nutrition and Functional Foods (INAF), Dairy Research Centre (STELA), Université Laval, Quebec City, Quebec, Canada
| | - Alice Marciniak
- Department of Food Sciences, Institute of Nutrition and Functional Foods (INAF), Dairy Research Centre (STELA), Université Laval, Quebec City, Quebec, Canada
| | - Yves Pouliot
- Department of Food Sciences, Institute of Nutrition and Functional Foods (INAF), Dairy Research Centre (STELA), Université Laval, Quebec City, Quebec, Canada
| | - Alain Doyen
- Department of Food Sciences, Institute of Nutrition and Functional Foods (INAF), Dairy Research Centre (STELA), Université Laval, Quebec City, Quebec, Canada
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β-Lactoglobulin Adsorption Layers at the Water/Air Surface: 5. Adsorption Isotherm and Equation of State Revisited, Impact of pH. COLLOIDS AND INTERFACES 2021. [DOI: 10.3390/colloids5010014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The theoretical description of the adsorption of proteins at liquid/fluid interfaces suffers from the inapplicability of classical formalisms, which soundly calls for the development of more complicated adsorption models. A Frumkin-type thermodynamic 2-d solution model that accounts for nonidealities of interface enthalpy and entropy was proposed about two decades ago and has been continuously developed in the course of comparisons with experimental data. In a previous paper we investigated the adsorption of the globular protein β-lactoglobulin at the water/air interface and used such a model to analyze the experimental isotherms of the surface pressure, Π(c), and the frequency-, f-, dependent surface dilational viscoelasticity modulus, E(c)f, in a wide range of protein concentrations, c, and at pH 7. However, the best fit between theory and experiment proposed in that paper appeared incompatible with new data on the surface excess, Γ, obtained from direct measurements with neutron reflectometry. Therefore, in this work, the same model is simultaneously applied to a larger set of experimental dependences, e.g., Π(c), Γ(c), E(Π)f, etc., with E-values measured strictly in the linear viscoelasticity regime. Despite this ambitious complication, a best global fit was elaborated using a single set of parameter values, which well describes all experimental dependencies, thus corroborating the validity of the chosen thermodynamic model. Furthermore, we applied the model in the same manner to experimental results obtained at pH 3 and pH 5 in order to explain the well-pronounced effect of pH on the interfacial behavior of β-lactoglobulin. The results revealed that the propensity of β-lactoglobulin globules to unfold upon adsorption and stretch at the interface decreases in the order pH 3 > pH 7 > pH 5, i.e., with decreasing protein net charge. Finally, we discuss advantages and limitations in the current state of the model.
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21
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Bergfreund J, Diener M, Geue T, Nussbaum N, Kummer N, Bertsch P, Nyström G, Fischer P. Globular protein assembly and network formation at fluid interfaces: effect of oil. SOFT MATTER 2021; 17:1692-1700. [PMID: 33393584 DOI: 10.1039/d0sm01870h] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The formation of viscoelastic networks at fluid interfaces by globular proteins is essential in many industries, scientific disciplines, and biological processes. However, the effect of the oil phase on the structural transitions of proteins, network formation, and layer strength at fluid interfaces has received little attention. Herein, we present a comprehensive study on the effect of oil polarity on globular protein networks. The formation dynamics and mechanical properties of the interfacial networks of three different globular proteins (lysozyme, β-lactoglobulin, and bovine serum albumin) were studied with interfacial shear and dilatational rheometry. Furthermore, the degree of protein unfolding at the interfaces was evaluated by subsequent injection of disulfide bonds reducing dithiothreitol. Finally, we measured the interfacial layer thickness and protein immersion into the oil phase with neutron reflectometry. We found that oil polarity significantly affects the network formation, the degree of interfacial protein unfolding, interfacial protein location, and the resulting network strength. These results allow predicting emulsion stabilization of proteins, tailoring interfacial layers with desired mechanical properties, and retaining the protein structure and functionality upon adsorption.
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Affiliation(s)
- Jotam Bergfreund
- Institute of Food, Nutrition and Health, ETH Zürich, 8092 Zürich, Switzerland.
| | - Michael Diener
- Institute of Food, Nutrition and Health, ETH Zürich, 8092 Zürich, Switzerland.
| | - Thomas Geue
- Laboratory of Neutron Scattering and Imaging, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Natalie Nussbaum
- Institute of Food, Nutrition and Health, ETH Zürich, 8092 Zürich, Switzerland.
| | - Nico Kummer
- Institute of Food, Nutrition and Health, ETH Zürich, 8092 Zürich, Switzerland. and Laboratory for Cellulose & Wood Materials, Swiss Federal Laboratories for Materials Science and Technology (Empa), Dübendorf, 8600, Switzerland
| | - Pascal Bertsch
- Institute of Food, Nutrition and Health, ETH Zürich, 8092 Zürich, Switzerland.
| | - Gustav Nyström
- Institute of Food, Nutrition and Health, ETH Zürich, 8092 Zürich, Switzerland. and Laboratory for Cellulose & Wood Materials, Swiss Federal Laboratories for Materials Science and Technology (Empa), Dübendorf, 8600, Switzerland
| | - Peter Fischer
- Institute of Food, Nutrition and Health, ETH Zürich, 8092 Zürich, Switzerland.
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22
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Bergfreund J, Bertsch P, Fischer P. Adsorption of proteins to fluid interfaces: Role of the hydrophobic subphase. J Colloid Interface Sci 2021; 584:411-417. [DOI: 10.1016/j.jcis.2020.09.118] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 08/31/2020] [Accepted: 09/09/2020] [Indexed: 12/18/2022]
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Bertsch P, Böcker L, Mathys A, Fischer P. Proteins from microalgae for the stabilization of fluid interfaces, emulsions, and foams. Trends Food Sci Technol 2021. [DOI: 10.1016/j.tifs.2020.12.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Guckeisen T, Hosseinpour S, Peukert W. Effect of pH and urea on the proteins secondary structure at the water/air interface and in solution. J Colloid Interface Sci 2021; 590:38-49. [PMID: 33524719 DOI: 10.1016/j.jcis.2021.01.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/05/2021] [Accepted: 01/06/2021] [Indexed: 01/09/2023]
Abstract
HYPOTHESIS The secondary structure of proteins affects their functionality and performance in physiological environments or industrial applications. Change of the solution pH or the presence of protein denaturants are the main chemical means that can alter the secondary structure of proteins or lead to protein denaturation. Since proteins in the bulk solution and those residing at the solution/air interface experience different local environments, their response to chemical denaturation can be different. EXPERIMENTS We utilize circular dichroism and chiral/achiral sum frequency generation spectroscopy to study the secondary structure of selected proteins as a function of the solution pH or in the presence of 8 M urea in the bulk solution and at the solution/air interface, respectively. FINDINGS The liquid/air interface can enhance or decrease protein conformation stability. The change in the secondary structure of the surface adsorbed proteins in alkaline solutions occurs at pH values lower than those denaturing the studied proteins in the bulk solution. In contrast, while 8 M urea completely denatures the studied proteins in the bulk solution, the liquid/air interface prevents the urea-induced denaturation of the surface adsorbed proteins by limiting the access of urea to the hydrophobic side chains of proteins protruding to air.
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Affiliation(s)
- Tobias Guckeisen
- Institute of Particle Technology (LFG), Friedrich-Alexander-Universität-Erlangen-Nürnberg (FAU), Cauerstraße 4, 91058 Erlangen, Germany.
| | - Saman Hosseinpour
- Institute of Particle Technology (LFG), Friedrich-Alexander-Universität-Erlangen-Nürnberg (FAU), Cauerstraße 4, 91058 Erlangen, Germany.
| | - Wolfgang Peukert
- Institute of Particle Technology (LFG), Friedrich-Alexander-Universität-Erlangen-Nürnberg (FAU), Cauerstraße 4, 91058 Erlangen, Germany.
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25
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Keppler JK, Heyse A, Scheidler E, Uttinger MJ, Fitzner L, Jandt U, Heyn TR, Lautenbach V, Loch JI, Lohr J, Kieserling H, Günther G, Kempf E, Grosch JH, Lewiński K, Jahn D, Lübbert C, Peukert W, Kulozik U, Drusch S, Krull R, Schwarz K, Biedendieck R. Towards recombinantly produced milk proteins: Physicochemical and emulsifying properties of engineered whey protein beta-lactoglobulin variants. Food Hydrocoll 2021. [DOI: 10.1016/j.foodhyd.2020.106132] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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26
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Lutz-Bueno V, Bolisetty S, Azzari P, Handschin S, Mezzenga R. Self-Winding Gelatin-Amyloid Wires for Soft Actuators and Sensors. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2004941. [PMID: 33103302 DOI: 10.1002/adma.202004941] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 09/21/2020] [Indexed: 05/20/2023]
Abstract
The origin of self-winding mechanisms in plants' tendrils has fascinated scientists for centuries and continues to inspire developments in material science and nanotechnology. Here, bioinspired water-responsive wires that replicate these mechanisms, including the formation of coils and chiral perversions, are presented. A right-handed gelatin matrix is loaded with rigid left-handed amyloid fibrils and roll-dry-spun into wires in which self-winding activation emerges from simultaneous bending and twisting deformations. Wire bending is a consequence of amyloid fibrils' concentration and distribution within the wire, whereas twisting is controlled by amyloid fibrils' orientation. The resultant wires can be functionalized by organic molecules and inorganic nanoparticles, and potential applications in magnetic actuators and sensors are demonstrated. The simple fabrication method and the remarkable spontaneous self-winding response of these gelatin-amyloid wires exemplify how biomaterials based on mixed proteins have striking potential to develop advanced and tunable properties that can serve robotics, soft machines, and engineering systems.
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Affiliation(s)
- Viviane Lutz-Bueno
- Department of Health Sciences and Technology, ETH Zürich, Zürich, 8092, Switzerland
| | - Sreenath Bolisetty
- Department of Health Sciences and Technology, ETH Zürich, Zürich, 8092, Switzerland
| | - Paride Azzari
- Department of Health Sciences and Technology, ETH Zürich, Zürich, 8092, Switzerland
| | - Stephan Handschin
- Department of Health Sciences and Technology, ETH Zürich, Zürich, 8092, Switzerland
| | - Raffaele Mezzenga
- Department of Health Sciences and Technology, ETH Zürich, Zürich, 8092, Switzerland
- Department of Materials, ETH Zurich, Zurich, 8093, Switzerland
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27
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Kurz F, Hengst C, Kulozik U. RP-HPLC method for simultaneous quantification of free and total thiol groups in native and heat aggregated whey proteins. MethodsX 2020; 7:101112. [PMID: 33194562 PMCID: PMC7644750 DOI: 10.1016/j.mex.2020.101112] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 10/14/2020] [Indexed: 11/27/2022] Open
Abstract
Disulfide formation of whey proteins during heat treatment via thiol oxidation is important with regard to techno-functional properties. Due to the formation of other oxidation products than disulfides, the decrease in free thiol concentration is not proportional to the disulfide formation. Thus, in order to evaluate thiol reactivity and disulfide concentration both parameters are required. Currently applied methods focus mainly on the loss of free thiols using the spectrophotometric Ellman's assay. Next to that, we improved an existing RP-HPLC assay using the thiol reagent 4,4′-Dithiodipyridine (DTDP) to quantify free thiols as well as total (free thiols and disulfide bonds) thiols of native and heat-treated whey proteins. Thereby, the sample preparation technique, the sample handling, and the analysis technique were optimized. Thus, the paper provides a simple RP-HPLC method for quantification of thiol oxidation reactions to determine heat-induced changes in the structure of whey proteins. In addition, the method should be applicable to other protein systems due to the method validation by proteins of different amounts of free and total thiols in their structure.Simple RP-HPLC method for quantification of free and total thiols using 4,4′-Dithiodipyridine (DTDP). High recovery rates for free and total thiols. High stability within 24 h.
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Affiliation(s)
- Franziska Kurz
- Chair of Food and Bioprocess Engineering, Technical University of Munich, Freising, Germany
| | - Claudia Hengst
- Chair of Food and Bioprocess Engineering, Technical University of Munich, Freising, Germany
| | - Ulrich Kulozik
- Chair of Food and Bioprocess Engineering, Technical University of Munich, Freising, Germany
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28
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Paradiso VM, Flamminii F, Pittia P, Caponio F, Mattia CD. Radical Scavenging Activity of Olive Oil Phenolic Antioxidants in Oil or Water Phase during the Oxidation of O/W Emulsions: An Oxidomics Approach. Antioxidants (Basel) 2020; 9:antiox9100996. [PMID: 33076439 PMCID: PMC7602588 DOI: 10.3390/antiox9100996] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 10/11/2020] [Accepted: 10/13/2020] [Indexed: 01/02/2023] Open
Abstract
Omics approaches are recently being applied also in food lipid oxidation, to increase knowledge of oxidation and antioxidation mechanisms. The so-called oxidomics throws a wider spot of light on the complex patterns of reactions taking place in food lipids, especially in dispersed systems. This research aimed to investigate the radical scavenging activity of olive oil phenolic antioxidants (OPAs) in O/W emulsions, as affected by the phase in which they were added. This allowed one to assess whether different behaviors could be expected from antioxidants originally present in phenolic-rich olive oils compared to natural antioxidants added in the water phase during emulsion production. Hydroperoxide decomposition kinetics and the analysis of volatile pattern provided an outline of antioxidation mechanisms. Though being effective in slowing down oxidation when added both in the oil and water phase, OPAs interfered in different ways with oxidation pathways, based on the phase in which they were added. OPAs added to the water phase were more effective in slowing down hydroperoxide decomposition due to the hydrophilic radical initiator. On the other hand, OPAs present in the oil were more effective in preventing radical propagation, with relevant consequences on the volatile pattern.
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Affiliation(s)
- Vito Michele Paradiso
- Department of Biological and Environmental Sciences and Technologies, University of Salento, I-73100 Lecce, Italy
- Department of Soil, Plant and Food Sciences, University of Bari, I-70126 Bari, Italy;
- Correspondence: (V.M.P.); (C.D.M.); Tel.: +39-080-544-2272 (V.M.P.); +39-086-126-6912 (C.D.M.)
| | - Federica Flamminii
- Faculty of Bioscience and Technology for Agriculture, Food and Environment, University of Teramo, I-64100 Teramo, Italy; (F.F.); (P.P.)
| | - Paola Pittia
- Faculty of Bioscience and Technology for Agriculture, Food and Environment, University of Teramo, I-64100 Teramo, Italy; (F.F.); (P.P.)
| | - Francesco Caponio
- Department of Soil, Plant and Food Sciences, University of Bari, I-70126 Bari, Italy;
| | - Carla Di Mattia
- Faculty of Bioscience and Technology for Agriculture, Food and Environment, University of Teramo, I-64100 Teramo, Italy; (F.F.); (P.P.)
- Correspondence: (V.M.P.); (C.D.M.); Tel.: +39-080-544-2272 (V.M.P.); +39-086-126-6912 (C.D.M.)
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29
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Dachmann E, Nobis V, Kulozik U, Dombrowski J. Surface and foaming properties of potato proteins: Impact of protein concentration, pH value and ionic strength. Food Hydrocoll 2020. [DOI: 10.1016/j.foodhyd.2020.105981] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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30
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Li Z, Chen TH, Andini E, Coffman JL, Przybycien T, Zydney AL. Enhanced filtration performance using feed-and-bleed configuration for purification of antibody precipitates. Biotechnol Prog 2020; 37:e3082. [PMID: 32940015 DOI: 10.1002/btpr.3082] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/24/2020] [Accepted: 09/14/2020] [Indexed: 11/10/2022]
Abstract
Precipitation can be used for the initial purification of monoclonal antibodies (mAbs), with the soluble host cell proteins removed in the permeate by tangential flow microfiltration. The objective of this study was to examine the use of a feed-and-bleed configuration to increase the effective conversion (ratio of permeate to feed flow rates) in the hollow fiber module to enable more effective washing of the precipitate. Experiments were performed using human serum Immunoglobulin G (IgG) precipitates formed with 10 mM zinc chloride and 7 wt% polyethylene glycol. The critical flux was evaluated as a function of the shear rate and IgG concentration, with the resulting correlation used to predict conditions that can achieve 90% conversion in a single pass with minimal fouling. Experimental data for both the start-up and steady-state performance are in good agreement with model calculations. These results were used to analyze the performance of an enhanced continuous precipitation-microfiltration process using the feed-and-bleed configuration for the initial capture / purification of a mAb product.
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Affiliation(s)
- Zhao Li
- Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Ting-Hsi Chen
- Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Erha Andini
- Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Jonathan L Coffman
- BioProcess Technologies and Engineering, AstraZeneca, Gaithersburg, Maryland, USA
| | - Todd Przybycien
- Department of Chemical & Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York, USA
| | - Andrew L Zydney
- Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania, USA
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31
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Synchrotron micro-CT for studying coarsening in milk protein-stabilized foams in situ. Colloids Surf A Physicochem Eng Asp 2020. [DOI: 10.1016/j.colsurfa.2020.124832] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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32
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Chemical composition, protein profile and physicochemical properties of whey protein concentrate ingredients enriched in α-lactalbumin. J Food Compost Anal 2020. [DOI: 10.1016/j.jfca.2020.103546] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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33
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Quevedo M, Kulozik U, Karbstein HP, Emin MA. Influence of Thermomechanical Treatment and Ratio of β-Lactoglobulin and α-Lactalbumin on the Denaturation and Aggregation of Highly Concentrated Whey Protein Systems. Foods 2020; 9:E1196. [PMID: 32872486 PMCID: PMC7555948 DOI: 10.3390/foods9091196] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 08/21/2020] [Accepted: 08/27/2020] [Indexed: 11/22/2022] Open
Abstract
The influence of thermomechanical treatment (temperature 60 °C-100 °C and shear rate 0.06 s-1-50 s-1) and mixing ratio of β-lactoglobulin (βLG) and α-lactalbumin (αLA) (5:2 and 1:1) on the denaturation and aggregation of whey protein model systems with a protein concentration of 60% and 70% (w/w) was investigated. An aggregation onset temperature was determined at approx. 80 °C for both systems (5:2 and 1:1 mixing ratio) with a protein concentration of 70% at a shear rate of 0.06 s-1. Increasing the shear rate up to 50 s-1 led to a decrease in the aggregation onset temperature independent of the mixing ratio. By decreasing the protein concentration to 60% in unsheared systems, the aggregation onset temperature decreased compared to that at a protein concentration of 70%. Furthermore, two significantly different onset temperatures were determined when the shear rate was increased to 25 s-1 and 50 s-1, which might result from a shear-induced phase separation. Application of combined thermal and mechanical treatment resulted in overall higher degrees of denaturation independent of the mixing ratio and protein concentration. At the conditions applied, the aggregation of the βLG and αLA mixtures was mainly due to the formation of non-covalent bonds. Although the proportion of disulfide bond aggregation increased with treatment temperature and shear rate, it was higher at a mixing ratio of 5:2 compared to that at 1:1.
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Affiliation(s)
- Maria Quevedo
- Institute of Process Engineering in Life Sciences, Chair of Food Process Engineering, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany; (M.Q.); (H.P.K.)
| | - Ulrich Kulozik
- Chair of Food and Bioprocess Engineering, Technical University of Munich, 85354 Freising, Germany;
| | - Heike P. Karbstein
- Institute of Process Engineering in Life Sciences, Chair of Food Process Engineering, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany; (M.Q.); (H.P.K.)
| | - M. Azad Emin
- Institute of Process Engineering in Life Sciences, Chair of Food Process Engineering, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany; (M.Q.); (H.P.K.)
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34
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β-Lactoglobulin Adsorption Layers at the Water/Air Surface: 4. Impact on the Stability of Foam Films and Foams. MINERALS 2020. [DOI: 10.3390/min10070636] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The complexity and high sensitivity of proteins to environmental factors give rise to a multitude of variables, which affect the stabilization mechanisms in protein foams. Interfacial and foaming properties of proteins have been widely studied, but the reported unique effect of pH, which can be of great interest to applications, has been investigated to a lesser extent. In this paper, we focus on the impact of pH on the stability of black foam films and corresponding foams obtained from solutions of a model globular protein—the whey β-lactoglobulin (BLG). Foam stability was analyzed utilizing three characteristic parameters (deviation time, transition time and half-lifetime) for monitoring the foam decay, while foam film stability was measured in terms of the critical disjoining pressure of film rupture. We attempt to explain correlations between the macroscopic properties of a foam system and those of its major building blocks (foam films and interfaces), and thus, to identify structure-property relationships in foam. Good correlations were found between the stabilities of black foam films and foams, while relations to the properties of adsorption layers appeared to be intricate. That is because pH-dependent interfacial properties of proteins usually exhibit an extremum around the isoelectric point (pI), but the stability of BLG foam films increases with increasing pH (3–7), which is well reflected in the foam stability. We discuss the possible reasons behind these intriguingly different behaviors on the basis of pH-induced changes in the molecular properties of BLG, which seem to be determining the mechanism of film rupture at the critical disjoining pressure.
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35
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Quevedo M, Kulozik U, Karbstein HP, Emin MA. Kinetics of denaturation and aggregation of highly concentrated β-Lactoglobulin under defined thermomechanical treatment. J FOOD ENG 2020. [DOI: 10.1016/j.jfoodeng.2019.109825] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Leeb E, Stefan T, Letzel T, Hinrichs J, Kulozik U. Tryptic hydrolysis of β-lactoglobulin: A generic approach to describe the hydrolysis kinetic and release of peptides. Int Dairy J 2020. [DOI: 10.1016/j.idairyj.2020.104666] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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37
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Quevedo M, Kulozik U, Karbstein HP, Emin MA. Effect of thermomechanical treatment on the aggregation behaviour and colloidal functionality of β-Lactoglobulin at high concentrations. Int Dairy J 2020. [DOI: 10.1016/j.idairyj.2020.104654] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Impact of Preheating Temperature on the Separation of Whey Proteins When Combined with Chemical or Bipolar Membrane Electrochemical Acidification. Int J Mol Sci 2020; 21:ijms21082792. [PMID: 32316425 PMCID: PMC7215982 DOI: 10.3390/ijms21082792] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 04/14/2020] [Accepted: 04/15/2020] [Indexed: 11/23/2022] Open
Abstract
Separation of α-lactalbumin and β-lactoglobulin improves their respective nutritional and functional properties. One strategy to improve their fractionation is to modify their pH and ionic strength to induce the selective aggregation and precipitation of one of the proteins of interest. Electrodialysis with bipolar membrane (EDBM) is a green process that simultaneously provides acidification and demineralization of a solution without adding any chemical compounds. This research presents the impact on whey proteins separation of different preheating temperatures (20, 50, 55 and 60 °C) combined with EDBM or chemical acidification of 10% whey protein isolate solutions. A β-lactoglobulin fraction at 81.8% purity was obtained in the precipitate after EDBM acidification and preheated at 60 °C, representing a recovery yield of 35.8%. In comparison, chemical acidification combined with a 60 °C preheating treatment provides a β-lactoglobulin fraction at 70.9% purity with a 11.6% recovery yield. The combination of EDBM acidification with a preheating treatment at 60 °C led to a better separation of the main whey proteins than chemical acidification.
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Milk protein fractionation by spiral-wound microfiltration membranes in diafiltration mode - Influence of feed protein concentration and composition on the filtration performance. Int Dairy J 2020. [DOI: 10.1016/j.idairyj.2019.104606] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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40
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Haller N, Kulozik U. Continuous centrifugal separation of selectively precipitated α-lactalbumin. Int Dairy J 2020. [DOI: 10.1016/j.idairyj.2019.104566] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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41
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Hartinger M, Napiwotzki J, Schmid EM, Kurz F, Kulozik U. Semi-quantitative, spatially resolved analysis of protein deposit layers on membrane surfaces. MethodsX 2019; 7:100780. [PMID: 31993341 PMCID: PMC6974784 DOI: 10.1016/j.mex.2019.100780] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 12/16/2019] [Indexed: 11/19/2022] Open
Abstract
Fouling distinctly reduces the filtration performance of membranes. A characterization of the fouling in membranes, however, is difficult due to its spatial distribution. Currently applied methods for deposit layer analysis are rather complex or do not offer a spatial resolution. Knowledge of the spatial distribution, however, could be used to improve the design of membranes, modules, and spacers. Staining with Coomassie Brilliant Blue, related to the staining of PAGE gels, is a simple method to visualize and analyze the deposited proteins semi-quantitatively. We improved an existing staining technique for protein deposits on membranes by adding a calibration for the semi-quantitative analysis and optimizing the sample handling. The method provides a spatially resolved analysis of deposited proteins up to a concentration of 10 g m−2. Apart from staining, data processing is described in order to generate false colors or topographic images of deposits. Thus, the paper describes a simple method to assess and visualize the influence of module characteristics such as spacer design on the spatially resolved protein fouling of polymeric and ceramic membranes. Therefore, the method can contribute to the improvement of the module design and processing conditions with regard to the filtration performance. Visualization of proteinaceous deposits on membranes Spatially resolved quantification of proteinaceous deposits
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Gochev GG, Scoppola E, Campbell RA, Noskov BA, Miller R, Schneck E. β-Lactoglobulin Adsorption Layers at the Water/Air Surface: 3. Neutron Reflectometry Study on the Effect of pH. J Phys Chem B 2019; 123:10877-10889. [PMID: 31725291 DOI: 10.1021/acs.jpcb.9b07733] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Several characteristics of β-lactoglobulin (BLG) layers adsorbed at the air/water interface exhibit a strong pH dependence, but our knowledge on the underlying structure-property relations is still fragmental. Here, we therefore extend our recent studies by neutron reflectometry (NR) and provide a comprehensive overview through direct measurements of the surface excess Γ and the layers' molecular structure. This enables comparison with available literature data to draw general conclusions. The NR experiments were performed at various pH values and within a wide range of protein concentrations, CBLG. Adsorption kinetics measurements in air-contrast-matched-water and over a narrow Qz range enabled direct quantification of the dynamic surface excess Γ(t) and are found to be consistent with ellipsometry data. Near the isoelectric point, pI, the rates of adsorption and Γ are maximal but only at sufficiently high CBLG. NR data collected over a wider Qz range and in two aqueous isotopic contrasts revealed the structure of adsorbed BLG layers at a steady state close to equilibrium. Independent of the pH, BLG was found to form dense monolayers with average thicknesses of 1.1 nm, suggesting flattening of the BLG globules upon adsorption as compared with their bulk dimensions (≈3.5 nm). Near pI and at sufficiently high CBLG, a thick (≈5.5 nm) but looser secondary sublayer is additionally formed adjacent to the dense primary monolayer. The thickness of this sublayer can be interpreted in terms of disordered BLG dimers. The results obtained and notably the specific interfacial structuring of BLG near pI complement previous observations relating the impact of solution pH and CBLG on other interfacial characteristics such as surface pressure and surface dilational viscoelasticity modulus.
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Affiliation(s)
- Georgi G Gochev
- Max Planck Institute of Colloids and Interfaces , 14476 Potsdam , Germany.,Institute of Physical Chemistry , Bulgarian Academy of Sciences , 1113 Sofia , Bulgaria
| | - Ernesto Scoppola
- Max Planck Institute of Colloids and Interfaces , 14476 Potsdam , Germany
| | - Richard A Campbell
- Institut Laue-Langevin , 71 Avenue des Martyrs, CS20156 , 38042 Grenoble , France.,Division of Pharmacy and Optometry , University of Manchester , M13 9PT Manchester , U.K
| | - Boris A Noskov
- Institute of Chemistry , St. Petersburg State University , 198504 Saint-Petersburg , Russia
| | - Reinhard Miller
- Max Planck Institute of Colloids and Interfaces , 14476 Potsdam , Germany
| | - Emanuel Schneck
- Max Planck Institute of Colloids and Interfaces , 14476 Potsdam , Germany
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Investigation on the influence of high protein concentrations on the thermal reaction behaviour of β-lactoglobulin by experimental and numerical analyses. Int Dairy J 2019. [DOI: 10.1016/j.idairyj.2019.06.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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44
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Richert ME, Gochev GG, Braunschweig B. Specific Ion Effects of Trivalent Cations on the Structure and Charging State of β-Lactoglobulin Adsorption Layers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:11299-11307. [PMID: 31398284 DOI: 10.1021/acs.langmuir.9b01803] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The properties of proteins at interfaces are important to many processes as well as in soft matter materials such as aqueous foam. Particularly, the protein interfacial behavior is strongly linked to different factors like the solution pH or the presence of electrolytes. Here, the nature of the electrolyte ions can significantly modify the interfacial properties of proteins. Therefore, molecular level studies on interfacial structures and charging states are needed. In this work, we addressed the effects of Y3+ and Nd3+ cations on the adsorption of the whey protein β-lactoglobulin (BLG) at air-water interfaces as the function of electrolyte concentration. Both cations caused very similar but dramatic changes at the interface and in the bulk solution. Here, measurements of the electrophoretic mobility and with vibrational sum-frequency generation (SFG) spectroscopy were applied and consistently showed a reversal of the BLG net charge at remarkably low ion concentrations of 30 (bulk) and 40 (interface) μM of Y3+ or Nd3+ for a BLG concentration of 15 μM. SFG spectra of carboxylate stretching vibrations from Asp or Glu residues of interfacial BLG showed significant changes in the resonance frequency, which we associate to specific and efficient binding of Y3+ or Nd3+ ions to the proteins carboxylate groups. Characteristic reentrant condensation for BLG moieties with bound trivalent ions was found in a broad concentration range around the point of zero net charge. The highest colloidal stability of BLG was found for ion concentrations <20 μM and >50 μM. Investigations on macroscopic foams from BLG solutions revealed the existence of structure-property relations between the interfacial charging state and the foam stability. In fact, a minimum in foam stability at 20 μM ion concentration was found when the interfacial net charge was negligible. At this concentration, we propose that the persistent BLG molecules and weakly charged BLG aggregates drive foam stability, while outside the bulk reentrant zone the electrostatic disjoining pressure inside foam lamellae dominates foam stability. Our results provide new information on the charge reversal at the liquid-gas interface of protein/ion dispersions. Therefore, we see our findings as an important step in the clarification of reentrant condensation effects at interfaces and their relevance to foam stability.
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Affiliation(s)
- Manuela E Richert
- Institute of Physical Chemistry and Center for Soft Nanoscience , Westfälische Wilhelms-Universität Münster Corrensstraße 28/30 , 48149 Münster , Germany
| | - Georgi G Gochev
- Institute of Physical Chemistry and Center for Soft Nanoscience , Westfälische Wilhelms-Universität Münster Corrensstraße 28/30 , 48149 Münster , Germany
| | - Björn Braunschweig
- Institute of Physical Chemistry and Center for Soft Nanoscience , Westfälische Wilhelms-Universität Münster Corrensstraße 28/30 , 48149 Münster , Germany
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Bertsch P, Thoma A, Bergfreund J, Geue T, Fischer P. Transient measurement and structure analysis of protein-polysaccharide multilayers at fluid interfaces. SOFT MATTER 2019; 15:6362-6368. [PMID: 31298681 DOI: 10.1039/c9sm01112a] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The formation of electrostatic protein-polysaccharide multilayers has attracted attention for the design of fluid interfaces with enhanced stability and functionality. However, current techniques are often limited to measuring final multilayer properties. We present an interfacial shear rheology setup with simultaneous subphase exchange, allowing the transient measurement of biopolymer multilayers by their viscoelasticity. The successive and simultaneous adsorption of β-lactoglobulin (β-lg) and low-methoxyl pectin were investigated at the n-dodecane/water interface at pH 4. The successive injection of pectin increased the viscoelasticity of an adsorbed β-lg layer by electrostatic complexation. On the other hand, simultaneous adsorption impeded adsorption kinetics and interfacial layer strength due to complexation in the bulk phase prior to adsorption. Neutron reflectometry at the air-water interface confirmed the formation of an initial β-lg layer and electrostatic complexation of a secondary pectin layer, which desorbed upon pH-induced charge inversion. The layer formed by simultaneous adsorption mainly consisted of β-lg. We conclude that protein-polysaccharide complexes show limited surface activity and result in a lower effective protein concentration available for adsorption.
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Affiliation(s)
- Pascal Bertsch
- Institute of Food Nutrition and Health, ETH Zurich, 8092 Zurich, Switzerland.
| | - Alexandra Thoma
- Institute of Food Nutrition and Health, ETH Zurich, 8092 Zurich, Switzerland.
| | - Jotam Bergfreund
- Institute of Food Nutrition and Health, ETH Zurich, 8092 Zurich, Switzerland.
| | - Thomas Geue
- Laboratory of Neutron Scattering and Imaging, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Peter Fischer
- Institute of Food Nutrition and Health, ETH Zurich, 8092 Zurich, Switzerland.
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Barone G, O'Regan J, O'Mahony JA. Influence of composition and microstructure on bulk handling and rehydration properties of whey protein concentrate powder ingredients enriched in α-lactalbumin. J FOOD ENG 2019. [DOI: 10.1016/j.jfoodeng.2019.02.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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47
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Wijaya W, Harfieyanto RC, Dewettinck K, Patel AR, Van der Meeren P. Whey protein isolate-low methoxyl pectin nanocomplexes improve physicochemical and stability properties of quercetin in a model fat-free beverage. Food Funct 2019; 10:986-996. [PMID: 30702738 DOI: 10.1039/c8fo02350f] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this study, whey protein isolate (WPI)-low methoxyl pectin (LMP) electrostatic complexes were used to encapsulate quercetin (Q) in a model fat-free beverage system. The effect of the pH and WPI : LMP ratio was first studied to form soluble complexes with optimal physical properties, in terms of the hydrodynamic diameter, surface charge, and yield. Based on the results, pH 5.0 and a 2 : 1 (w/w) ratio of WPI : LMP were selected for encapsulation of Q. The stoichiometry of the binding (n) and the binding constant (Kb) of WPI:Q were evaluated at pH values of 5.0 and 7.0 at room temperature. The Q-loaded WPI:LMP nanocomplexes were produced by mixing WPI with Q at two loading concentrations corresponding to 5 : 1 and 1 : 1 WPI : Q molar mixing ratios, followed by the addition of LMP and pH adjustment to 5.0. The microstructure of Q-loaded WPI:LMP complexes was investigated by cryo-SEM imaging. Q was efficiently entrapped at two loading concentrations with an efficiency of about 97%. Q-loaded WPI:LMP complexes showed physical stability during storage and high temperature processing, as well as in the presence of challenging formulation conditions such as a high sugar concentration or salt addition (at a limited concentration). The stability of encapsulated Q against UV irradiation was approximately 4 times better than that of free Q. Moreover, Q-loaded WPI:LMP complexes were also lyophilized into dry powder, which can be useful for practical application in food products.
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Affiliation(s)
- Wahyu Wijaya
- Particle and Interfacial Technology Group, Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Gent, Belgium.
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Fractionation of casein micelles and minor proteins by microfiltration in diafiltration mode. Study of the transmission and yield of the immunoglobulins IgG, IgA and IgM. Int Dairy J 2019. [DOI: 10.1016/j.idairyj.2019.01.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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50
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