1
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Liu W, Feng Y, Delaplace G, André C, Chen XD. Effect of calcium on the reversible and irreversible thermal denaturation pathway of β-lactoglobulin. Food Hydrocoll 2022. [DOI: 10.1016/j.foodhyd.2022.107943] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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2
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Perez D, Harte F, Lopez-Pedemonte T. Ionic strength and buffering capacity of emulsifying salts determine denaturation and gelation temperatures of whey proteins. J Dairy Sci 2022; 105:7230-7241. [PMID: 35879172 DOI: 10.3168/jds.2021-21738] [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: 12/21/2021] [Accepted: 04/24/2022] [Indexed: 11/19/2022]
Abstract
Ionic conditions affect the denaturation and gelling of whey proteins, affecting the physical properties of foods in which proteins are used as ingredients. We comprehensively investigated the effect of the presence of commonly used emulsifying salts on the denaturation and gelling properties of concentrated solutions of β-lactoglobulin (β-LG) and whey protein isolate (WPI). The denaturation temperature in water was 73.5°C [coefficient of variation (CV) 0.49%], 71.8°C (CV 0.38%), and 69.9°C (CV 0.41%) for β-LG (14% wt/wt), β-LG (30% wt/wt), and WPI (30% wt/wt), respectively. Increasing the concentration of salts, except for sodium hexametaphosphate, resulted in a linear increase in the denaturation temperature of WPI (kosmotropic behavior) and an acceleration in its gelling rate. Sodium chloride and tartrate salts exhibited the strongest effect in protecting WPI against thermal denaturation. Despite the constant initial pH of all solutions, salts having buffering capacity (e.g., phosphate and citrate salts) prevented a decrease in pH as the temperature increased above 70°C, resulting in a decline in denaturation temperature at low salt concentrations (≤0.2 mol/g). When pH was kept constant at denaturation temperature, all salts except sodium hexametaphosphate, which exhibited chaotropic behavior, exhibited similar effects on denaturation temperature. At low salt concentration, gelation was the controlling step, occurring up to 10°C above denaturation temperature. At high salt concentration (>3% wt/wt), thermal denaturation was the controlling step, with gelation occurring immediately after. These results indicate that the ionic and buffering properties of salts added to milk will determine the native versus denatured state and gelation of whey proteins in systems subjected to high temperature, short time processing (72°C for 15 s).
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Affiliation(s)
- D Perez
- Unidad de Ciencia y Tecnología de Lácteos, Instituto Tecnológico Suroeste, Universidad Tecnológica del Uruguay, La Paz, Colonia Piamontesa, Colonia, 70200, Uruguay.
| | - F Harte
- Department of Food Science, Pennsylvania State University, University Park 16802
| | - T Lopez-Pedemonte
- Unidad de Ciencia y Tecnología de Lácteos, Instituto Tecnológico Suroeste, Universidad Tecnológica del Uruguay, La Paz, Colonia Piamontesa, Colonia, 70200, Uruguay
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3
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Bull SP, Khutoryanskiy VV, Parker JK, Faka M, Methven L. Oral retention of thermally denatured whey protein: In vivo measurement and structural observations by CD and NMR. Food Chem 2021; 374:131650. [PMID: 34915364 DOI: 10.1016/j.foodchem.2021.131650] [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: 02/04/2020] [Revised: 11/17/2021] [Accepted: 11/17/2021] [Indexed: 11/04/2022]
Abstract
This study investigated structural changes and the in vivo retention in the oral cavity of heated whey protein concentrate (WPC). Heated WPC was shown to have both a higher retention time in the oral cavity compared to unheated whey protein up to 1 min post swallow, and a concomitant increase in free thiol concentration. Nuclear magnetic resonance and circular dichroism demonstrated structural changes in the secondary and tertiary structures of the WPC upon heating. Structural loss of the β-barrel was shown to increase during heating, leading to the exposure of hydrophobic regions. The increase in free thiols and hydrophobic regions are two factors which are known to increase mucoadhesive strength and hence increase oral retention of heated whey protein which may subsequently increase the perception of mouthdrying.
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Affiliation(s)
- Stephanie P Bull
- Department of Food and Nutritional Sciences, University of Reading, Whiteknights, Reading, Berks RG6 6AD, United Kingdom.
| | - Vitaliy V Khutoryanskiy
- Department of Pharmacy, University of Reading, Whiteknights, Reading, Berks RG6 6AD, United Kingdom.
| | - Jane K Parker
- Department of Food and Nutritional Sciences, University of Reading, Whiteknights, Reading, Berks RG6 6AD, United Kingdom.
| | - Marianthi Faka
- Volac International Ltd, 50 Fishers Lane, Orwell, Royston, Hertfordshire SG8 5QX, United Kingdom.
| | - Lisa Methven
- Department of Food and Nutritional Sciences, University of Reading, Whiteknights, Reading, Berks RG6 6AD, United Kingdom.
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4
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Walshe EJ, O’Regan J, O’Mahony JA. Influence of protein content and profile on the processing characteristics and physical properties of model infant formula powders. INT J DAIRY TECHNOL 2021. [DOI: 10.1111/1471-0307.12788] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Emma J Walshe
- Nestle Development Centre Nutrition Askeaton, Co. Limerick Ireland
- School of Food and Nutritional Sciences University College Cork Cork Ireland
| | - Jonathan O’Regan
- Nestle Development Centre Nutrition Askeaton, Co. Limerick Ireland
| | - James A O’Mahony
- School of Food and Nutritional Sciences University College Cork Cork Ireland
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5
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Influence of Processing Temperature on Membrane Performance and Characteristics of Process Streams Generated during Ultrafiltration of Skim Milk. Foods 2020; 9:foods9111721. [PMID: 33238626 PMCID: PMC7700131 DOI: 10.3390/foods9111721] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 11/12/2020] [Accepted: 11/19/2020] [Indexed: 11/17/2022] Open
Abstract
The effects of processing temperature on filtration performance and characteristics of retentates and permeates produced during ultrafiltration (UF) of skim milk at 5, 20, and 50 °C were investigated. The results indicate that despite higher flux at 50 °C, UF under these conditions resulted in greater fouling and rapid flux decline in comparison with 5 and 20 °C. The average casein micelle diameter was higher in retentate produced at 5 and 20 °C. The retentate analysed at 5 °C displayed higher viscosity and shear thinning behaviour as compared to retentate analysed at 20 and 50 °C. Greater permeation of calcium and phosphorus was observed at 5 and 20 °C in comparison with 50 °C, which was attributed to the inverse relationship between temperature and solubility of colloidal calcium phosphate. Permeation of α-lactalbumin was observed at all processing temperatures, with permeation of β-lactoglobulin also evident during UF at 50 °C. All UF retentates were shown to have plasmin activity, while lower activity was measured in retentate produced at 5 °C. The findings revealed that UF processing temperature influences the physicochemical, rheological, and biochemical properties of, and thereby govern the resulting quality and functionality of, retentate- and permeate-based dairy ingredients.
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6
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Bonarek P, Loch JI, Tworzydło M, Cooper DR, Milto K, Wróbel P, Kurpiewska K, Lewiński K. Structure-based design approach to rational site-directed mutagenesis of β-lactoglobulin. J Struct Biol 2020; 210:107493. [PMID: 32169624 DOI: 10.1016/j.jsb.2020.107493] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 03/06/2020] [Accepted: 03/09/2020] [Indexed: 12/30/2022]
Abstract
Recombinant proteins play an important role in medicine and have diverse applications in industrial biotechnology. Lactoglobulin has shown great potential for use in targeted drug delivery and body fluid detoxification because of its ability to bind a variety of molecules. In order to modify the biophysical properties of β-lactoglobulin, a series of single-site mutations were designed using a structure-based approach. A 3-dimensional structure alignment of homologous molecules led to the design of nine β-lactoglobulin variants with mutations introduced in the binding pocket region. Seven stable and correctly folded variants (L39Y, I56F, L58F, V92F, V92Y, F105L, M107L) were thoroughly characterized by fluorescence, circular dichroism, isothermal titration calorimetry, size-exclusion chromatography, and X-ray structural investigations. The effects of the amino acid substitutions were observed as slight rearrangements of the binding pocket geometry, but they also significantly influenced the global properties of the protein. Most of the mutations increased the thermal/chemical stability without altering the dimerization constant or pH-dependent conformational behavior. The crystal structures reveal that the I56F and F105L mutations reduced the depth of the binding pocket, which is advantageous since it can reduce the affinity to endogenous fatty acids. The F105L mutant created a unique binding mode for a fatty acid, supporting the idea that lactoglobulin can be altered to bind unique molecules. Selected variants possessing a unique combination of their individual properties can be used for further, more advanced mutagenesis, and the presented results support further research using β-lactoglobulin as a therapeutic delivery agent or a blood detoxifying molecule.
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Affiliation(s)
- Piotr Bonarek
- Jagiellonian University, Faculty of Biochemistry, Biophysics and Biotechnology, Gronostajowa 7, 30-387 Kraków, Poland
| | - Joanna I Loch
- Jagiellonian University, Faculty of Chemistry, Gronostajowa 2, 30-387 Kraków, Poland
| | - Magdalena Tworzydło
- Jagiellonian University, Faculty of Biochemistry, Biophysics and Biotechnology, Gronostajowa 7, 30-387 Kraków, Poland
| | - David R Cooper
- University of Virginia, Department of Molecular Physiology and Biological Physics, 1340 Jefferson Park Avenue, Charlottesville, VA 22908, USA
| | - Katažyna Milto
- Jagiellonian University, Faculty of Biochemistry, Biophysics and Biotechnology, Gronostajowa 7, 30-387 Kraków, Poland
| | - Paulina Wróbel
- Jagiellonian University, Faculty of Chemistry, Gronostajowa 2, 30-387 Kraków, Poland
| | - Katarzyna Kurpiewska
- Jagiellonian University, Faculty of Chemistry, Gronostajowa 2, 30-387 Kraków, Poland
| | - Krzysztof Lewiński
- Jagiellonian University, Faculty of Chemistry, Gronostajowa 2, 30-387 Kraków, Poland.
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7
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Schwaighofer A, Alcaraz MR, Lux L, Lendl B. pH titration of β-lactoglobulin monitored by laser-based Mid-IR transmission spectroscopy coupled to chemometric analysis. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2020; 226:117636. [PMID: 31610466 DOI: 10.1016/j.saa.2019.117636] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 09/27/2019] [Accepted: 10/07/2019] [Indexed: 06/10/2023]
Abstract
A novel external cavity-quantum cascade laser (EC-QCL)-based setup for mid-IR transmission spectroscopy in the amide I and amide II region was employed for monitoring pH-induced changes of protein secondary structure. pH titration of β-lactoglobulin revealed unfolding of the native β-sheet secondary structure occurring at basic pH. Chemometric analysis of the dynamic IR spectra was performed by multivariate curve resolution-alternating least squares (MCR-ALS). Using this approach, spectral and abundance distribution profiles of the conformational transition were obtained. A proper post-processing procedure was implemented allowing to extract information about pure protein spectra and spurious signals that may interfere in the interpretation of the system. This work demonstrates the potential and versatility of the EC-QCL-based IR transmission setup for flow-through applications, benefitting from the high available optical path length.
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Affiliation(s)
- Andreas Schwaighofer
- Institute of Chemical Technologies and Analytics, Vienna University of Technology, Getreidemarkt 9/164-UPA, 1060, Vienna, Austria
| | - Mirta R Alcaraz
- Laboratorio de Desarrollo Analítico y Quimiometría (LADAQ), Cátedra de Química Analítica I, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Ciudad Universitaria, Santa Fe, S3000ZAA, Argentina; Departamento de Química Inorgánica, Analítica y Química Física, INQUIMAE, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Pabellón 2, Buenos Aires, C1428EGA, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz, 2290 CABA, C1425FQB, Argentina
| | - Laurin Lux
- Institute of Chemical Technologies and Analytics, Vienna University of Technology, Getreidemarkt 9/164-UPA, 1060, Vienna, Austria
| | - Bernhard Lendl
- Institute of Chemical Technologies and Analytics, Vienna University of Technology, Getreidemarkt 9/164-UPA, 1060, Vienna, Austria.
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8
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Rodrigues RM, Claro B, Bastos M, Pereira RN, Vicente AA, Petersen SB. Multi-step thermally induced transitions of β-lactoglobulin – An in situ spectroscopy approach. Int Dairy J 2020. [DOI: 10.1016/j.idairyj.2019.104562] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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9
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Singh R, Meena NK, Das T, Sharma RD, Prakash A, Lynn AM. Delineating the conformational dynamics of intermediate structures on the unfolding pathway of β-lactoglobulin in aqueous urea and dimethyl sulfoxide. J Biomol Struct Dyn 2019; 38:5027-5036. [PMID: 31744390 DOI: 10.1080/07391102.2019.1695669] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The funnel shaped energy landscape model of the protein folding suggests that progression of folding proceeds through multiple pathways, having the multiple intermediates which leads to multidimensional free-energy surface. Herein, we applied all-atom MD simulation to conduct a comparative study on the structure of β-lactoglobulin (β-LgA) in aqueous mixture of 8 M urea and 8 M dimethyl sulfoxide (DMSO), at different temperatures. The cumulative results of multiple simulations suggest a common unfolding pathway of β-LgA, occurred through the stable and meta-stable intermediates (I), in both urea and DMSO. However, the free-energy landscape (FEL) analyses show that the structural transitions of I-states are energetically different. In urea, FEL shows distinct ensemble of intermediates, I1 and I2, separated by the energy barrier of ∼3.0 kcal mol-1. Similarly, we find the population of two distinct I1 and I2 states in DMSO, however, the I1 appeared transiently around ∼30-35 ns and is short-lived. But, the I2 ensemble is observed structurally compact and long-lived (∼50-150 ns) as compared to unfolding in urea. Furthermore, the I1 and I2 are separated through a high energy barrier of ∼6.0 kcal mol-1. Thus, our results provide the structural insights of intermediates which essentially bear the signature of a different unfolding pathway of β-LgA in urea and DMSO.Abbreviationsβ-LgAβ-lactoglobulinDMSOdimethyl sulfoxideFELfree-energy landscapeGdmClguanidinium chlorideIintermediate stateMGmolten globule statePMEparticle mesh EwaldQfraction of native contactsRMSDroot mean square deviationRMSFroot mean square fluctuationRgradius of gyrationSASAsolvent Accessible Surface AreascSASAthe side chain SASATrptryptophanCommunicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Ruhar Singh
- School of Computational & Integrative Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Naveen Kumar Meena
- School of Computational & Integrative Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Trishala Das
- School of Computational & Integrative Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Ravi Datta Sharma
- Amity Institute of Integrative Sciences and Health, Amity University, Haryana, India
| | - Amresh Prakash
- Amity Institute of Integrative Sciences and Health, Amity University, Haryana, India
| | - Andrew M Lynn
- School of Computational & Integrative Sciences, Jawaharlal Nehru University, New Delhi, India
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10
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Pandey P, Meena NK, Prakash A, Kumar V, Lynn AM, Ahmad F. Characterization of heterogeneous intermediate ensembles on the guanidinium chloride-induced unfolding pathway of β-lactoglobulin. J Biomol Struct Dyn 2019; 38:1042-1053. [PMID: 30880641 DOI: 10.1080/07391102.2019.1593245] [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] [Indexed: 12/20/2022]
Abstract
Folding pathway of β-LgA (β-lactoglobulin) evolves through the conformational α→β transition. The α→β transition is a molecular hallmark of various neurodegenerative diseases. Thus, β-LgA may serve as a good model for understanding molecular mechanism of protein aggregation involved in neurodegenerative diseases. Here, we studied the conformational dynamics of β-LgA in 6 M GdmCl at different temperatures using MD simulations. Structural order parameters such as RMSD, Rg, SASA, native contacts (Q), hydrophobic distal-matrix and free-energy landscape (FEL) were used to investigate the conformational transitions. Our results show that GdmCl destabilizes secondary and tertiary structure of β-LgA by weakening the hydrophobic interactions and hydrogen bond network. Multidimensional FEL shows the presence of different unfolding intermediates at 400 K. I1 is long-lived intermediate which has mostly intact native secondary structure, but loose tertiary structure. I2 is structurally compact intermediate formed after the partial loss of secondary structure. The transiently and infrequently buried evolution of W19 shows that intermediate conformational ensembles are structurally heterogeneous. We observed that the intermediate conformations are largely stabilized by non-native H-bonds. The outcome of this work provides the molecular details of intermediates trapped due to non-native interactions that may be regarded as pathogenic conformations involved in neurodegenerative diseases.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Preeti Pandey
- School of Computational & Integrative Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Naveen Kumar Meena
- School of Computational & Integrative Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Amresh Prakash
- School of Computational & Integrative Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Vijay Kumar
- Amity Institute of Neuropsychology & Neurosciences, Amity University, Noida, India
| | - Andrew M Lynn
- School of Computational & Integrative Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Faizan Ahmad
- Jamia Millia Islamia, Centre for Interdisciplinary Research in Basic Sciences, New Delhi, India
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11
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Bogahawaththa D, Chandrapala J, Vasiljevic T. Thermal denaturation of bovine β-lactoglobulin in different protein mixtures in relation to antigenicity. Int Dairy J 2019. [DOI: 10.1016/j.idairyj.2018.10.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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12
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Buggy AK, McManus JJ, Brodkorb A, Hogan SA, Fenelon MA. Pilot-scale formation of whey protein aggregates determine the stability of heat-treated whey protein solutions—Effect of pH and protein concentration. J Dairy Sci 2018; 101:10819-10830. [DOI: 10.3168/jds.2017-14177] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 07/10/2018] [Indexed: 11/19/2022]
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13
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Sun X, Wang C, Wang H, Guo M. Effects of Processing on Structure and Thermal Properties of Powdered Preterm Infant Formula. J Food Sci 2018; 83:1685-1694. [PMID: 29745984 DOI: 10.1111/1750-3841.14162] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 03/21/2018] [Accepted: 03/22/2018] [Indexed: 12/31/2022]
Abstract
Powdered infant formula is usually manufactured by ingredients mixing, homogenization, pasteurization, evaporation and spray drying. Effects of unit operations on the microstructure, thermal properties and other characteristics of preterm infant formula, fat (F), serum (S), and pellet (P) fractions on centrifugation were investigated using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Differential Scanning Calorimetry (DSC), and Fourier Transform Infrared (FTIR) spectroscopy. After homogenization, particles which may be casein and denatured whey proteins were observed on the surface of F fraction in microstructure images. DSC results showed that the onset temperature of the second endothermic peak of F fraction shifted to higher temperature, and an endothermic transition appeared at 173.3 °C in P fraction. The -CH2 group corresponding to F fraction showed less intensity in FTIR spectrum after homogenization. Microstructure images for S and P fractions showed larger aggregates due to the pasteurization processing. Apparent exothermic transition in DSC curve occurred at 101.6 °C indicated whey protein aggregation. Spray drying resulted in some open areas in F fraction and lager aggregates in S fraction revealed by microstructure pictures. A new exothermic transition appeared at 93.6 °C in DSC curve of S fraction. Changes in amide I and amide II regions in FTIR spectra of samples resulted from pasteurization and spray drying indicated the changes in secondary structure of casein and whey proteins. All results indicated that homogenization, pasteurization, and spray drying exhibited pronounced impacts on the microstructure, thermal properties and structural characteristics of samples. PRACTICAL APPLICATION Preterm infant formula is an important dairy food for preborn infants. Our results indicate that unit operations especially homogenization, pasteurization, and spray drying during the processing have the most impacts on the microstructure, thermal properties and other characteristics of infant formula. This work provides further understanding of component interactions during the processing of infant formula and theoretical basis for the production of dairy food.
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Affiliation(s)
- Xiaomeng Sun
- Dept. of Food Science, College of Food Science and Engineering, Jilin Univ., Changchun, Jilin 130062, China
| | - Cuina Wang
- Dept. of Food Science, College of Food Science and Engineering, Jilin Univ., Changchun, Jilin 130062, China
| | - Hao Wang
- Dept. of Food Science, College of Food Science and Engineering, Jilin Univ., Changchun, Jilin 130062, China
| | - Mingruo Guo
- Dept. of Food Science, College of Food Science and Engineering, Jilin Univ., Changchun, Jilin 130062, China.,Dept. of Nutrition and Food Sciences, College of Agriculture and Life Sciences, Univ. of Vermont, Burlington, Vt. 05405, U.S.A.,Dept. of Food Science, Northeast Agriculture Univ., Harbin, Heilongjiang 150030, China
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14
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Ng KS, Dunstan DE, Martin GJ. Influence of processing temperature on flux decline during skim milk ultrafiltration. Sep Purif Technol 2018. [DOI: 10.1016/j.seppur.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] [Indexed: 10/18/2022]
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15
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Sengupta B, Das N, Sen P. Monomerization and aggregation of β-lactoglobulin under adverse condition: A fluorescence correlation spectroscopic investigation. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2018; 1866:316-326. [DOI: 10.1016/j.bbapap.2017.11.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2017] [Revised: 11/01/2017] [Accepted: 11/12/2017] [Indexed: 12/26/2022]
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16
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17
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Sutariya S, Patel H. Effect of hydrogen peroxide on improving the heat stability of whey protein isolate solutions. Food Chem 2017; 223:114-120. [DOI: 10.1016/j.foodchem.2016.12.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Revised: 11/04/2016] [Accepted: 12/07/2016] [Indexed: 10/20/2022]
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18
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Cheison SC, Kulozik U. Impact of the environmental conditions and substrate pre-treatment on whey protein hydrolysis: A review. Crit Rev Food Sci Nutr 2017; 57:418-453. [PMID: 25976220 DOI: 10.1080/10408398.2014.959115] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Proteins in solution are subject to myriad forces stemming from interactions with each other as well as with the solvent media. The role of the environmental conditions, namely pH, temperature, ionic strength remains under-estimated yet it impacts protein conformations and consequently its interaction with, and susceptibility to, the enzyme. Enzymes, being proteins are also amenable to the environmental conditions because they are either activated or denatured depending on the choice of the conditions. Furthermore, enzyme specificity is restricted to a narrow regime of optimal conditions while opportunities outside the optimum conditions remain untapped. In addition, the composition of protein substrate (whether mixed or single purified) have been underestimated in previous studies. In addition, protein pre-treatment methods like heat denaturation prior to hydrolysis is a complex phenomenon whose progression is influenced by the environmental conditions including the presence or absence of sugars like lactose, ionic strength, purity of the protein, and the molecular structure of the mixed proteins particularly presence of free thiol groups. In this review, we revisit protein hydrolysis with a focus on the impact of the hydrolysis environment and show that preference of peptide bonds and/or one protein over another during hydrolysis is driven by the environmental conditions. Likewise, heat-denaturing is a process which is dependent on not only the environment but the presence or absence of other proteins.
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Affiliation(s)
| | - Ulrich Kulozik
- b Chair for Food Process Engineering and Dairy Technology Department , ZIEL Technology Section, Technische Universität München , Weihenstephaner Berg 1, Freising , Germany
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19
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Schwaighofer A, Alcaráz MR, Araman C, Goicoechea H, Lendl B. External cavity-quantum cascade laser infrared spectroscopy for secondary structure analysis of proteins at low concentrations. Sci Rep 2016; 6:33556. [PMID: 27633337 PMCID: PMC5025714 DOI: 10.1038/srep33556] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 08/30/2016] [Indexed: 12/19/2022] Open
Abstract
Fourier transform infrared (FTIR) and circular dichroism (CD) spectroscopy are analytical techniques employed for the analysis of protein secondary structure. The use of CD spectroscopy is limited to low protein concentrations (<2 mg ml(-1)), while FTIR spectroscopy is commonly used in a higher concentration range (>5 mg ml(-1)). Here we introduce a quantum cascade laser (QCL)-based IR transmission setup for analysis of protein and polypeptide secondary structure at concentrations as low as 0.25 mg ml(-1) in deuterated buffer solution. We present dynamic QCL-IR spectra of the temperature-induced α-helix to β-sheet transition of poly-L-lysine. The concentration dependence of the α-β transition temperature between 0.25 and 10 mg ml(-1) was investigated by QCL-IR, FTIR and CD spectroscopy. By using QCL-IR spectroscopy it is possible to perform IR spectroscopic analysis in the same concentration range as CD spectroscopy, thus enabling a combined analysis of biomolecules secondary structure by CD and IR spectroscopy.
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Affiliation(s)
- Andreas Schwaighofer
- Institute of Chemical Technologies and Analytics, Vienna University of Technology, Getreidemarkt 9/164-UPA, 1060 Vienna, Austria
| | - Mirta R. Alcaráz
- Institute of Chemical Technologies and Analytics, Vienna University of Technology, Getreidemarkt 9/164-UPA, 1060 Vienna, Austria
- Laboratorio de Desarrollo Analítico y Quimiometría, FBCB, Universidad Nacional del Litoral-CONICET, Ciudad Universitaria, 3000 Santa Fe, Argentina
| | - Can Araman
- Department of Chemistry, Institute of Biological Chemistry, University of Vienna, Währinger Straße 38, 1090 Vienna, Austria
| | - Héctor Goicoechea
- Laboratorio de Desarrollo Analítico y Quimiometría, FBCB, Universidad Nacional del Litoral-CONICET, Ciudad Universitaria, 3000 Santa Fe, Argentina
| | - Bernhard Lendl
- Institute of Chemical Technologies and Analytics, Vienna University of Technology, Getreidemarkt 9/164-UPA, 1060 Vienna, Austria
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20
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Jørgensen CE, Abrahamsen RK, Rukke EO, Johansen AG, Schüller RB, Skeie SB. Optimization of protein fractionation by skim milk microfiltration: Choice of ceramic membrane pore size and filtration temperature. J Dairy Sci 2016; 99:6164-6179. [DOI: 10.3168/jds.2016-11090] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 04/29/2016] [Indexed: 11/19/2022]
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21
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Guo M, Wang G. Whey protein polymerisation and its applications in environmentally safe adhesives. INT J DAIRY TECHNOL 2016. [DOI: 10.1111/1471-0307.12303] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mingruo Guo
- Department of Food Science; Jilin University; Changchun 130012 China
- Department of Nutrition and Food Sciences; University of Vermont; Burlington VT 05405 USA
| | - Guorong Wang
- Department of Nutrition and Food Sciences; University of Vermont; Burlington VT 05405 USA
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22
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Neurath AR, Debnath AK, Strick N, Li YY, Lin K, Jiang S. 3-Hydroxyphthaloyl-β-Lactoglobulin. I. Optimization of Production and Comparison with other Compounds Considered for Chemoprophylaxis of Mucosally Transmitted Human Immunodeficiency Virus Type 1. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/095632029700800207] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Modification of the major bovine whey protein, β-lactoglobulin (β-LG) by 3-hydroxyphthalic anhydride (3HP) leads to the generation of a potent inhibitor of infection by human immunodeficiency virus (HIV) types 1 and 2, designated 3HP-β-LG. 3HP-β-LG also has antiviral activity against herpesviruses, albeit at concentrations exceeding those required for inhibition of HIV-1 infection. The topical application of 3HP-β-LG to decrease the rate of sexual transmission of HIV and other sexually transmitted viruses worldwide is being considered. Results presented here: (i) define the conditions for chemical modification of β-LG by 3HP, resulting in 3HP-β-LG with optimum anti-HIV-1 activity; (ii) show that β-LG, prior to chemical modification, or 3HP-β-LG can be exposed to the elevated temperatures used to pasteurize milk without adversely affecting anti-HIV-1 activity; (iii) provide evidence that 3HP-β-LG is a more potent anti-HIV-1 compound than sulphated polysaccharides, other candidate compounds considered as prophylactic agents to prevent sexual transmission of HIV-1; and (iv) confirm that the primary target for 3HP-β-LG is CD4, although binding to the HIV-1 envelope protein gp120 was also observed and contributed to the antiviral activity of 3HP-β-LG.
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Affiliation(s)
- AR Neurath
- The Lindsley F Kimball Research Institute of the New York Blood Center, 310 E 67th Street, New York, NY 10021, USA
| | - AK Debnath
- The Lindsley F Kimball Research Institute of the New York Blood Center, 310 E 67th Street, New York, NY 10021, USA
| | - N Strick
- The Lindsley F Kimball Research Institute of the New York Blood Center, 310 E 67th Street, New York, NY 10021, USA
| | - Y-Y Li
- The Lindsley F Kimball Research Institute of the New York Blood Center, 310 E 67th Street, New York, NY 10021, USA
| | - K Lin
- The Lindsley F Kimball Research Institute of the New York Blood Center, 310 E 67th Street, New York, NY 10021, USA
| | - S Jiang
- The Lindsley F Kimball Research Institute of the New York Blood Center, 310 E 67th Street, New York, NY 10021, USA
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23
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Lighezan L, Georgieva R, Neagu A. The secondary structure and the thermal unfolding parameters of the S-layer protein from Lactobacillus salivarius. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2016; 45:491-509. [DOI: 10.1007/s00249-016-1117-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 01/26/2016] [Accepted: 02/10/2016] [Indexed: 11/28/2022]
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24
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25
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Steinhauer T, Marx M, Bogendörfer K, Kulozik U. Membrane fouling during ultra- and microfiltration of whey and whey proteins at different environmental conditions: The role of aggregated whey proteins as fouling initiators. J Memb Sci 2015. [DOI: 10.1016/j.memsci.2015.04.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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26
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Murphy EG, Fenelon MA, Roos YH, Hogan SA. Decoupling macronutrient interactions during heating of model infant milk formulas. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2014; 62:10585-10593. [PMID: 25251787 DOI: 10.1021/jf503620r] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Understanding macronutrient interactions during heating is important for controlling viscosity during infant milk formula (IMF) manufacture. Thermal behavior of macronutrients (casein, whey, lactose, fat) was studied, in isolation and combination, over a range of concentrations. Addition of phosphocasein to whey protein solutions elevated denaturation temperature (Td) of β-lactoglobulin and the temperature at which viscosity started to increase upon heating (Tv). Secondary structural changes in whey proteins occurred at higher temperatures in dispersions containing phosphocasein; the final extent of viscosity increase was similar to that of whey protein alone. Addition of lactose to whey protein solutions delayed secondary structural changes, increased Td and Tv, and reduced post heat treatment viscosity. This study demonstrated that heat-induced changes in IMF associated with whey protein (denaturation, viscosity) are not only a function of concentration but are also dependent on interactions between macronutrients.
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Affiliation(s)
- Eoin G Murphy
- Food Chemistry and Technology Department, Teagasc Food Research Centre , Moorepark, Fermoy, County Cork, Ireland
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28
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Butré CI, Sforza S, Gruppen H, Wierenga PA. Determination of the influence of substrate concentration on enzyme selectivity using whey protein Isolate and Bacillus licheniformis protease. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2014; 62:10230-10239. [PMID: 25270540 DOI: 10.1021/jf503151f] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Increasing substrate concentration during enzymatic protein hydrolysis results in a decrease in hydrolysis rate. To test if changes in the mechanism of hydrolysis also occur, the enzyme selectivity was determined. The selectivity is defined quantitatively as the relative rate of hydrolysis of each cleavage site in the protein. It was determined from the identification and quantification of the peptides present in the hydrolysates. Solutions of 0.1-10% (w/v) whey protein isolate (WPI) were hydrolyzed by Bacillus licheniformis protease at constant enzyme-to-substrate ratio. The cleavage sites were divided into five groups, from very high (>10%) to very low selectivity (<0.1%). The selectivity toward cleavage sites after Glu 62 and 134 was 2 times higher at 10% (w/v) WPI than at the lower protein concentrations. This finding shows that both the rate of hydrolysis and the enzyme selectivity were influenced by the substrate concentration.
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Affiliation(s)
- Claire I Butré
- Laboratory of Food Chemistry, Wageningen University , Postbus 17, 6700 AA Wageningen, The Netherlands
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29
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Ryan KN, Zhong Q, Foegeding EA. Use of whey protein soluble aggregates for thermal stability-a hypothesis paper. J Food Sci 2014; 78:R1105-15. [PMID: 23957418 DOI: 10.1111/1750-3841.12207] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 06/05/2013] [Indexed: 11/27/2022]
Abstract
Forming whey proteins into soluble aggregates is a modification shown to improve or expand the applications in foaming, emulsification, gelation, film-formation, and encapsulation. Whey protein soluble aggregates are defined as aggregates that are intermediates between monomer proteins and an insoluble gel network or precipitate. The conditions under which whey proteins denature and aggregate have been extensively studied and can be used as guiding principles of producing soluble aggregates. These conditions are reviewed for pH, ion type and concentration, cosolutes, and protein concentration, along with heating temperature and duration. Combinations of these conditions can be used to design soluble aggregates with desired physicochemical properties including surface charge, surface hydrophobicity, size, and shape. These properties in turn can be used to obtain target macroscopic properties, such as viscosity, clarity, and stability, of the final product. A proposed approach to designing soluble aggregates with improved thermal stability for beverage applications is presented.
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Affiliation(s)
- Kelsey N Ryan
- Donald Danforth Plant Science Center, Washington Univ. School of Medicine, St. Louis, MO 63110, USA
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30
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31
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Haug I, Carlsen AM, Vegarud G, Langsrud T, Draget K. Textural Properties of Beta-lactoglobulin - Sodium Alginate Mixed Gels at Large Scale Deformation. J Texture Stud 2012; 44:56-65. [DOI: 10.1111/j.1745-4603.2012.00365.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Accepted: 06/18/2012] [Indexed: 11/28/2022]
Affiliation(s)
- I.J. Haug
- Norwegian Biopolymer Laboratory (NOBIPOL); Institute of Biotechnology; Norwegian University of Science and Technology (NTNU); N-7491; Trondheim; Norway
| | - A.-M.H. Carlsen
- Norwegian Biopolymer Laboratory (NOBIPOL); Institute of Biotechnology; Norwegian University of Science and Technology (NTNU); N-7491; Trondheim; Norway
| | - G.E. Vegarud
- Institute of Chemistry, Biotechnology and Food Science (IKBM); Norwegian University of Life science (UMB); Aas; Norway
| | - T. Langsrud
- Institute of Chemistry, Biotechnology and Food Science (IKBM); Norwegian University of Life science (UMB); Aas; Norway
| | - K.I. Draget
- Norwegian Biopolymer Laboratory (NOBIPOL); Institute of Biotechnology; Norwegian University of Science and Technology (NTNU); N-7491; Trondheim; Norway
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32
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Thermodynamic and structural analysis of homodimeric proteins: Model of β-lactoglobulin. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2012; 1824:383-91. [DOI: 10.1016/j.bbapap.2011.11.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Revised: 11/23/2011] [Accepted: 11/29/2011] [Indexed: 11/19/2022]
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33
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Wakayama J, Sugiyama S. Evaluation of Temperature Effect on the Interaction between β-Lactoglobulin and Anti-β-lactoglobulin Antibody by Atomic Force Microscopy. Biochemistry 2011; 51:32-42. [DOI: 10.1021/bi201245k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jun’ichi Wakayama
- Nano-Biotechnology Laboratory, Food
Engineering Division, National Food Research Institute, National Agriculture and Food Research Organization, 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan
| | - Shigeru Sugiyama
- Nano-Biotechnology Laboratory, Food
Engineering Division, National Food Research Institute, National Agriculture and Food Research Organization, 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan
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34
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Bateman L, Ye A, Singh H. Re-formation of fibrils from hydrolysates of β-lactoglobulin fibrils during in vitro gastric digestion. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2011; 59:9605-9611. [PMID: 21790203 DOI: 10.1021/jf2020057] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
In this study, in vitro digestion of β-lactoglobulin (β-Lg) fibrils and the re-formation of fibril-like structures after prolonged enzymatic hydrolysis (up to 48 h) were investigated using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), thioflavin T fluorescence photometry, and transmission electron microscopy (TEM). Pure β-Lg fibrils that had been formed by heat treatment at pH 2.0 were rapidly hydrolyzed by pepsin in the simulated gastric fluid (pH 1.2), and some new peptides that were suitable for further fibril formation were produced. TEM showed that the new fibrils were long and straight but thinner than the original fibrils, and both TEM and MALDI-MS indicated that the peptides in the new fibrils were shorter/smaller than the peptides in the original fibrils. The formation of new fibrils was found to be affected more by pH than by enzyme activity or temperature.
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Affiliation(s)
- Libei Bateman
- Riddet Institute, Massey University, Private Bag 11 222, Palmerston North 4442, New Zealand
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35
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Cold, gel-like whey protein emulsions by microfluidisation emulsification: Rheological properties and microstructures. Food Chem 2011. [DOI: 10.1016/j.foodchem.2011.02.031] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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36
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Hansted JG, Wejse PL, Bertelsen H, Otzen DE. Effect of protein-surfactant interactions on aggregation of β-lactoglobulin. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2011; 1814:713-23. [PMID: 21440683 DOI: 10.1016/j.bbapap.2011.03.011] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Revised: 03/16/2011] [Accepted: 03/17/2011] [Indexed: 11/26/2022]
Abstract
The milk protein β-lactoglobulin (βLG) dominates the properties of whey aggregates in food products. Here we use spectroscopic and calorimetric techniques to elucidate how anionic, cationic and non-ionic surfactants interact with bovine βLG and modulate its heat-induced aggregation. Alkyl trimethyl ammonium chlorides (xTAC) strongly promote aggregation, while sodium alkyl sulfates (SxS) and alkyl maltopyranosides (xM) reduce aggregation. Sodium dodecyl sulfate (SDS) binds to non-aggregated βLG in several steps, but reduction of aggregation was associated with the first binding step, which occurs far below the critical micelle concentration. In contrast, micellar concentrations of xMs are required to reduce aggregation. The ranking order for reduction of aggregation (normalized to their tendency to self-associate) was C10-C12>C8>C14 for SxS and C8>C10>C12>C14>C16 for xM. xTAC promote aggregation in the same ranking order as xM reduce it. We conclude that SxS reduce aggregation by stabilizing the protein's ligand-bound state (the melting temperature t(m) increases by up to 10°C) and altering its charge potential. xM monomers also stabilize the protein's ligand-bound state (increasing t(m) up to 6°C) but in the absence of charged head groups this is not sufficient by itself to prevent aggregation. Although micelles of both anionic and non-ionic surfactants destabilize βLG, they also solubilize unfolded protein monomers, leaving them unavailable for protein-protein association and thus inhibiting aggregation. Cationic surfactants promote aggregation by a combination of destabilization and charge neutralization. The food compatible surfactant sodium dodecanoate also inhibited aggregation well below the cmc, suggesting that surfactants may be a practical way to modulate whey protein properties.
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Affiliation(s)
- Jon G Hansted
- Department of Molecular Biology, Aarhus University, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark
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37
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Kehoe JJ, Foegeding EA. Interaction between β-casein and whey proteins as a function of pH and salt concentration. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2011; 59:349-355. [PMID: 21133408 DOI: 10.1021/jf103371g] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The effectiveness of β-casein as a chaperone in the aggregation of whey proteins was investigated. β-Casein altered heat-induced aggregation as shown by a reduction in turbidity of β-lactoglobulin, α-lactalbumin, and bovine serum albumin (BSA) solutions. The pH of the mixtures greatly affected how much β-casein reduced the turbidity of the solutions; the maximum reductions in turbidity were observed at pH 6.0. Reducing the pH decreased the effectiveness of β-casein as a chaperone. An increase in ionic strength by the addition of NaCl or CaCl(2) also decreased the effectiveness of the chaperone. The addition of CaCl(2) had a larger effect than the addition of NaCl. The chaperone effect was seen at temperatures up to 145 °C. Differential scanning calorimetry (DSC) showed that β-casein did not alter the denaturation temperature of β-lactoglobulin. The kinetics curves for loss of native protein and turbidity development showed that β-casein did not function by slowing the aggregation process. It was concluded that β-casein competes with whey protein in the aggregate process and the aggregates formed in the presence of β-casein are smaller in size than those formed during whey protein self-aggregation. The formation of smaller aggregates gives rise to less turbid, more soluble protein solutions.
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Affiliation(s)
- J J Kehoe
- Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University, Raleigh, North Carolina 27695-7624, USA
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38
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Bateman L, Ye A, Singh H. In vitro digestion of beta-lactoglobulin fibrils formed by heat treatment at low pH. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2010; 58:9800-9808. [PMID: 20684554 DOI: 10.1021/jf101722t] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Extensive studies have been done on beta-lactoglobulin (beta-Lg) fibrils in the past decade due to their potential as functional food ingredients, gelling agents, and encapsulation devices etc. (van der Goot, A. J.; Peighambardoust, S. H.; Akkermans, C.; van Oosten-Manski, J. M. Creating novel structures in food materials: The role of well-defined shear flow. Food Biophys. 2008, 3(2), 120-125 and Loveday, S. M.; Rao, M. A.; Creamer, L. K.; Singh, H. Factors affecting rheological characteristics of fibril gels: The case of beta-lactoglobulin and alpha-lactalbumin. J. Food Sci. 2009, 74 (3), R47-R55). However, most of the studies focus on the formation and mechanism of the fibrils. Little is known about fibril digestibility to date. In this work, in vitro pepsin digestion of bovine beta-lactoglobulin (beta-Lg) fibrils in simulated gastric fluid was investigated using thioflavin T fluorescence photometry, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, size-exclusion chromatography, matrix-assisted laser desorption/ionization mass spectrometry, and transmission electron microscopy (TEM). The fibrils were formed by heating beta-Lg solutions at 80 degrees C and pH 2.0 for 20 h. The fibrils were found to be digested completely by pepsin within 2 min, when long, straight fibrils were no longer observed by TEM. The peptides in the fibrils (2000-8000 Da) could be digested to smaller peptides (mostly <2000 Da) by pepsin. The peptides in the fibrils were believed to be more susceptible for pepsin to access and attack because of their hydrophobic nature. For comparison purposes, solutions of beta-Lg heated at neutral pH (pH 7.4) were also studied under the same conditions.
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Affiliation(s)
- Libei Bateman
- Riddet Institute, Massey University, Private Bag 11 222, Palmerston North 4442, New Zealand
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39
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Seo JA, Hédoux A, Guinet Y, Paccou L, Affouard F, Lerbret A, Descamps M. Thermal denaturation of beta-lactoglobulin and stabilization mechanism by trehalose analyzed from Raman spectroscopy investigations. J Phys Chem B 2010; 114:6675-84. [PMID: 20411964 DOI: 10.1021/jp1006022] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The thermal denaturation process of beta-lactoglobulin has been analyzed in the 20-100 degrees C temperature range by Raman spectroscopy experiments simultaneously performed in the region of amide modes (800-1800 cm(-1)) and in the low-frequency range (10-350 cm(-1)). The analysis of amide modes reveals a two-step thermal denaturation process in the investigated temperature range. The first step corresponds to the dissociation of dimers associated with an increase of flexibility of the tertiary structure. In the second step, large conformational changes are detected in the secondary structure and described as a loss of alpha-helix structures and a concomitant formation of beta-sheets. Raman investigations in the low-frequency range provide important information on the origin of the denaturation process through the analysis of the solvent dynamics and its coupling with that of the protein. The softening of the tetrahedral structure of water induces the dissociation of dimers and makes the tertiary structure softer, leading to the water penetration in the protein interior. The methodology based on Raman investigations of amide modes and in the low-frequency region was used to analyze the mechanism of beta-lactoglobulin thermostabilization by trehalose. The main effect of trehalose is determined to be related to its capabilities to distort the tetrahedral organization of water molecules.
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Affiliation(s)
- Jeong-Ah Seo
- Unité Matériaux Et Transformations, UMR CNRS 8207, Université de Lille 1, 59655 Villeneuve d Ascq Cédex, France
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40
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Effect of iron chelates on oil–water interface, stabilized by milk proteins: The role of phosphate groups and pH. Prediction of iron transfer from aqueous phase toward fat globule surface by changes of interfacial properties. Food Hydrocoll 2010. [DOI: 10.1016/j.foodhyd.2009.11.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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41
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Electrostatic effects on β-lactoglobulin transitions during heat denaturation as studied by differential scanning calorimetry. Food Hydrocoll 2009. [DOI: 10.1016/j.foodhyd.2009.06.006] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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42
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Interactions between β-lactoglobulin and dextran sulfate at near neutral pH and their effect on thermal stability. Food Hydrocoll 2009. [DOI: 10.1016/j.foodhyd.2008.09.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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43
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Effect of different heat treatments on the strong binding interactions between whey proteins and milk fat globules in whole milk. J DAIRY RES 2009. [DOI: 10.1017/s0022029900031940] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
SummaryThe heat-induced binding of whey proteins to milk fat globule membranes in whole milk was investigated by quantitative electrophoresis and laser scanning densitometry. Both α-lactalbumin and β-lactoglobulin bound to the surfaces of fat globules when milk was heated in a water bath in the temperature range 65–85 °C. The interaction behaviour of α-lactalbumin did not seem to change with temperature, and the total amount of protein bound was ∼ 0·2 mg/g fat contained in the cream. The quantity of βlactoglobulin interacting with the milk fat globules increased with temperature from 02 to 0·7 mg/g fat between 65° and 85 °C. Even in whole milk heated at batch pasteurization temperatures (60–65 °C), α-lactalbumin and β-lactoglobulin were found attached to the fat globules. The interactions of the whey proteins with intact fat globule membranes were also investigated in milk heated in an industrial system (a pilot scale UHT and high temperature short time module), and the results were compared with those from the laboratory treatment (simple batch heating). The binding of the whey proteins to fat globules differed between milk heated by UHT using indirect steam heating or direct steam injection (DSI). However, the surface load in milk treated by DSI was not comparable to that of milk treated by batch heating or indirect steam heating, because of the changes in fat globule size and membrane composition caused by the DSI process.
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44
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Mandalari G, Mackie AM, Rigby NM, Wickham MSJ, Mills ENC. Physiological phosphatidylcholine protects bovine β-lactoglobulin from simulated gastrointestinal proteolysis. Mol Nutr Food Res 2009; 53 Suppl 1:S131-9. [DOI: 10.1002/mnfr.200800321] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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45
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Belcher J, Sansone S, Fernandez NF, Haskins WE, Brancaleon L. Photoinduced unfolding of beta-lactoglobulin mediated by a water-soluble porphyrin. J Phys Chem B 2009; 113:6020-30. [PMID: 19351165 PMCID: PMC2735475 DOI: 10.1021/jp900957d] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
We investigated the effects that the irradiation of a tetra-anionic porphyrin (mesotetrakis(sulfonatophenyl)porphyrin) noncovalently bound to beta-lactoglobulin (BLG) produces on the conformation of the protein. Although BLG is not a potential target for the biomedical applications of porphyrins, it is a useful model for investigating the effects of photoactive ligands on small globular proteins. We show in this paper that irradiation causes a large unfolding of the protein and that the conformational change is not mediated by the formation of reactive oxygen species. Instead, our data are consistent with an electron-transfer mechanism that is capable of triggering structural changes in the protein and causes the Trp19 residue to undergo chemical modifications to form a derivative of kynurenine. This demonstrates that protein unfolding is prompted by a type-III photosensitizing mechanisms. Type-III mechanisms have been suggested previously, but they have been largely neglected as useful mediators of biomolecular damage. Our study demonstrates that porphyrins can be used as mediators of localized protein conformational changes and that the biomedical applications as well as the mechanistic details of electron transfer between exogenous ligands and proteins merit further investigation.
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Affiliation(s)
- John Belcher
- Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX, USA
| | - Samuel Sansone
- Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX, USA
| | - Nicholas F. Fernandez
- Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX, USA
| | - William E. Haskins
- Department of Biology, University of Texas at San Antonio, San Antonio, TX, USA
| | - Lorenzo Brancaleon
- Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX, USA
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46
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47
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48
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Yong YH, Foegeding EA. Effects of caseins on thermal stability of bovine beta-lactoglobulin. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2008; 56:10352-10358. [PMID: 18828604 DOI: 10.1021/jf801658u] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Casein fractions have been shown to act as molecular chaperones and inhibit aggregation of whey proteins in dilute solutions (< or =1% w/v). We evaluated if this approach would stabilize protein solutions at higher concentration and thermal processing temperatures desired for beverage applications. Mixtures of beta-lactoglobulin (BLG) (6% w/v) with either beta-casein (BCN) (0.01-2% w/v) or alpha s-casein (ACN) (2% w/v) were adjusted to pH 6.0 and heated (70-90 degrees C) for 20 min, cooled, and then analyzed to determine the degree of aggregation. Aggregation was determined by solution turbidity as optical density (OD) at 400 or 600 nm. The addition of 0.05% (w/v) BCN or greater caused a drop in turbidity for solutions heated at 70-90 degrees C. In contrast, inhibition was observed in BLG-ACN mixtures at 70 degrees C but not at > or =75 degrees C. Moreover, prolonged heating (90 min) of BLG with 2% (w/v) BCN (pH 6.0) at 90 degrees C produced a clear solution while BLG-ACN solutions formed translucent gels after heating for 15 min. The weight-averaged molar mass and root-mean-square (rms) radius of soluble aggregates were determined by size exclusion chromatography in conjunction with multiangle laser light scattering (SEC-MALS). SEC-MALS confirmed the turbidity results by showing that the BLG-BCN mixture (8% w/v protein) produced aggregates with lower molar mass and smaller rms radius (majority 20-40 nm). These results showed that BCN is a feasible component to stabilize higher concentrations of whey proteins in beverages.
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Affiliation(s)
- Yie Hui Yong
- Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University, Raleigh, North Carolina 27695-7624, USA
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Grácia-Juliá A, René M, Cortés-Muñoz M, Picart L, López-Pedemonte T, Chevalier D, Dumay E. Effect of dynamic high pressure on whey protein aggregation: A comparison with the effect of continuous short-time thermal treatments. Food Hydrocoll 2008. [DOI: 10.1016/j.foodhyd.2007.05.017] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Vardhanabhuti B, Allen Foegeding E. Effects of dextran sulfate, NaCl, and initial protein concentration on thermal stability of β-lactoglobulin and α-lactalbumin at neutral pH. Food Hydrocoll 2008. [DOI: 10.1016/j.foodhyd.2007.03.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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