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Zhang T, Chen S, Xu X, Zhuang X, Chen Y, Xue Y, Xue C, Jiang N. Effects of konjac glucomannan on physical properties and microstructure of fish myofibrillar protein gel: Phase behaviours involved. Food Hydrocoll 2022. [DOI: 10.1016/j.foodhyd.2022.108034] [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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2
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Heat-induced gel formation of a protein-rich extract from the microalga Chlorella sorokiniana. INNOV FOOD SCI EMERG 2019. [DOI: 10.1016/j.ifset.2019.06.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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3
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Impacts on Micro- and Macro-Structure of Thermally Stabilised Whey Protein-Pectin Complexes: A Fluorescence Approach. FOOD BIOPHYS 2016. [DOI: 10.1007/s11483-016-9433-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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4
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Li X, Liu Y, Li N, Xie D, Yu J, Wang F, Wang J. Studies of phase separation in soluble rice protein/different polysaccharides mixed systems. Lebensm Wiss Technol 2016. [DOI: 10.1016/j.lwt.2015.08.064] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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5
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Nguyen BT, Nicolai T, Benyahia L, Chassenieux C. The effect of the competition for calcium ions between κ-carrageenan and β-lactoglobulin on the rheology and the structure in mixed gels. Colloids Surf A Physicochem Eng Asp 2015. [DOI: 10.1016/j.colsurfa.2014.09.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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6
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Chun JY, Hong GP, Surassmo S, Weiss J, Min SG, Choi MJ. Study of the phase separation behaviour of native or preheated WPI with polysaccharides. POLYMER 2014. [DOI: 10.1016/j.polymer.2014.06.082] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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7
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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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8
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Martínez KD, Pilosof AM. Rheology and thermal transitions of enzymatically modified soy protein and polysaccharides mixtures, of potential use as foaming agent determined by response surface methodology. FOOD BIOSCI 2013. [DOI: 10.1016/j.fbio.2013.04.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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9
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Zhuo XY, Qi JR, Yin SW, Yang XQ, Zhu JH, Huang LX. Formation of soy protein isolate-dextran conjugates by moderate Maillard reaction in macromolecular crowding conditions. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2013; 93:316-323. [PMID: 22777841 DOI: 10.1002/jsfa.5760] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Revised: 03/23/2012] [Accepted: 05/13/2012] [Indexed: 06/01/2023]
Abstract
BACKGROUND Several methods have been reported for the conjugation of proteins with polysaccharides. Protein-polysaccharide conjugates can be formed by traditional dry heating, but this process is not attractive from an industrial viewpoint, and no commercial conjugates have been manufactured in this way. In the present study, in order to develop a more practical reaction method, macromolecular crowding was used to attach polysaccharides to proteins. RESULTS Soy protein isolate-dextran conjugates (SDCs) were prepared via the initial stage of the Maillard reaction in macromolecular crowding conditions. The impact of various processing conditions on the formation of SDCs was investigated. The optimal conditions chosen from the experiments were a soy protein isolate/dextran ratio of 1:1 (w/w), a pH of 6.5, a reaction temperature of 60 °C and a reaction time of 30 h. Circular dichroism spectroscopy showed that the secondary and tertiary structures of the conjugates were changed significantly. Structural flexibility increased, allowing better display of their functional characteristics. The conjugates had a composition with various sizes, especially macromolecules, according to gel permeation chromatography. Thermal analysis showed that the thermal stability of the conjugates was improved. CONCLUSION The production of SDCs under macromolecular crowding conditions appears to be an effective and promising technique, representing an advance over classic protein glycosylation methods.
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Affiliation(s)
- Xiu-Ying Zhuo
- School of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510640, Guangdong, China
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10
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Deep G, Hassan AN, Metzger L. Exopolysaccharides modify functional properties of whey protein concentrate. J Dairy Sci 2012; 95:6332-8. [PMID: 22939784 DOI: 10.3168/jds.2012-5649] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 06/22/2012] [Indexed: 11/19/2022]
Abstract
The objective of this research was to produce whey protein concentrate (WPC) with modified functionality using exopolysaccharide- (EPS) producing cultures. Two different EPS-producing cultures, Lactococcus lactis ssp. cremoris JFR and Streptococcus thermophilus, producing EPS1 and EPS2 respectively, were used in this study. One EPS-nonproducing commercial cheese culture (DVS 850; Chr. Hansen, Milwaukee, WI) was used as the control. Reconstituted sweet whey powder was used in this study to eliminate variations from fresh whey. Cultures grown overnight in reconstituted WPC (10% wt/vol) were added, directly or after overnight cooling (cooled EPS), at 2% (wt/vol) to 6% (wt/wt) solution of reconstituted whey. Whey was then high-temperature, short-time pasteurized at 75 °C for 35s and ultrafiltered to a volume reduction factor of 5. Ultrafiltered whey (retentate) was spray dried at inlet and outlet air temperatures of 200 and 90 °C, respectively, to obtain WPC. In general, the solubility of WPC was higher at pH 7 than at pH 3. Whey protein concentrate containing EPS2 exhibited higher protein solubility than did WPC containing no EPS. Also, the presence of EPS in WPC decreased protein denaturation. The emulsifying ability of WPC containing EPS was higher than that in control. Addition of EPS to WPC significantly enhanced its gelling ability. Foam overrun and hydrophobicity of WPC were not affected by addition of EPS. In conclusion, data obtained from this study show that EPS modify WPC functionality. The extent of modification depends on the type of EPS. Cooling of culture containing EPS before its addition to whey further reduced WPC protein denaturation and increased its solubility at pH 7 and gel hardness.
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Affiliation(s)
- G Deep
- Dairy Science Department, South Dakota State University, Brookings 57007, USA
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11
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Çakır E, Foegeding EA. Combining protein micro-phase separation and protein–polysaccharide segregative phase separation to produce gel structures. Food Hydrocoll 2011. [DOI: 10.1016/j.foodhyd.2011.02.002] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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12
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13
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Polysaccharide determination in protein/polysaccharide mixtures for phase-diagram construction. Carbohydr Polym 2010. [DOI: 10.1016/j.carbpol.2010.03.056] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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14
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Influence of Cross-linked Waxy Maize Starch on the Aggregation Behavior of Casein Micelles During Acid-induced Gelation. FOOD BIOPHYS 2010. [DOI: 10.1007/s11483-010-9164-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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15
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Abhyankar AR, Mulvihill DM, Fenelon MA, Auty MA. Microstructural characterization of β-lactoglobulin–konjac glucomannan systems: Effect of NaCl concentration and heating conditions. Food Hydrocoll 2010. [DOI: 10.1016/j.foodhyd.2009.07.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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16
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Li X, Liu Y, Yi C, Cheng Y, Zhou S, Hua Y. Microstructure and rheological properties of mixtures of acid-deamidated rice protein and dextran. J Cereal Sci 2010. [DOI: 10.1016/j.jcs.2009.08.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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17
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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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18
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Kontogiorgos V, Tosh SM, Wood PJ. Kinetics of Phase Separation of Oat β-Glucan/Whey Protein Isolate Binary Mixtures. FOOD BIOPHYS 2009. [DOI: 10.1007/s11483-009-9121-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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19
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Li X, Cheng Y, Yi C, Hua Y, Yang C, Cui S. Effect of ionic strength on the heat-induced soy protein aggregation and the phase separation of soy protein aggregate/dextran mixtures. Food Hydrocoll 2009. [DOI: 10.1016/j.foodhyd.2008.07.024] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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20
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Harrington J, Foegeding E, Mulvihill D, Morris E. Segregative interactions and competitive binding of Ca2+ in gelling mixtures of whey protein isolate with Na+ κ-carrageenan. Food Hydrocoll 2009. [DOI: 10.1016/j.foodhyd.2008.03.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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21
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Effect of protein–polysaccharide mixtures on the continuous manufacturing of foamed food products. Food Hydrocoll 2009. [DOI: 10.1016/j.foodhyd.2007.12.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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22
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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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23
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Kasapis S. Phase Separation in Biopolymer Gels: A Low- to High-Solid Exploration of Structural Morphology and Functionality. Crit Rev Food Sci Nutr 2008; 48:341-59. [DOI: 10.1080/10408390701347769] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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25
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Quiroga CC, Bergenståhl B. Phase segregation of amylopectin and β-lactoglobulin in aqueous system. Carbohydr Polym 2008. [DOI: 10.1016/j.carbpol.2007.07.041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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26
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Li X, Deng F, Hua Y, Qiu A, Yang C, Cui S. Effect of molecular weight of dextran on the phase behavior and microstructure of preheated soy protein/dextran mixtures. Carbohydr Polym 2008. [DOI: 10.1016/j.carbpol.2007.07.037] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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27
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Mounsey JS, O’Kennedy BT, Fenelon MA, Brodkorb A. The effect of heating on β-lactoglobulin–chitosan mixtures as influenced by pH and ionic strength. Food Hydrocoll 2008. [DOI: 10.1016/j.foodhyd.2007.04.006] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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28
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Leng X, Turgeon S. Study of the shear effects on the mixture of whey protein/polysaccharides—2: Application of flow models in the study of the shear effects on WPI/polysaccharide system. Food Hydrocoll 2007. [DOI: 10.1016/j.foodhyd.2006.03.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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29
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Ercelebi EA, Ibanoğlu E. Influence of hydrocolloids on phase separation and emulsion properties of whey protein isolate. J FOOD ENG 2007. [DOI: 10.1016/j.jfoodeng.2006.05.027] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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30
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Thermal denaturation and functional properties of egg proteins in the presence of hydrocolloid gums. Food Chem 2007. [DOI: 10.1016/j.foodchem.2006.01.056] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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31
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Baussay K, Durand D, Nicolai T. Coupling between polysaccharide gelation and micro-phase separation of globular protein clusters. J Colloid Interface Sci 2006; 304:335-41. [PMID: 17045288 DOI: 10.1016/j.jcis.2006.09.059] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2006] [Revised: 09/08/2006] [Accepted: 09/09/2006] [Indexed: 11/23/2022]
Abstract
The effect of gelation of the polysaccharide phase on the phase separation was investigated for mixtures of anionic polysaccharide (kappa-carrageenan) and globular protein (beta-lactoglobulin) clusters at pH 7 well above the iso-electric point. Gelation of kappa-carrageenan was induced by cooling in the presence of KCl. In the liquid state the protein clusters phase-separate into relatively dense micro-domains. When the polysaccharide phase gelled during cooling, the turbidity of the systems decreased dramatically. Light scattering experiments showed that the density of the micro-domains decreased, while microscopy showed that the number and size was not strongly modified. It is concluded that smaller protein clusters leave the micro-domains when kappa-carrageenan gels. The effect could be reversed by reheating the samples and thus melting the gel and was observed for repeated heating and cooling cycles. The effect of gelation on phase separation decreases with increasing polysaccharide concentration and with ageing of the liquid mixture. The latter is caused by the formation of bonds between the protein clusters in the micro-domains that slowly reinforce with time.
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Affiliation(s)
- Karine Baussay
- Polymères, Colloïdes, Interfaces, UMR CNRS, Université du Maine, 72085 Le Mans Cedex 9, France
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32
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Pérez OE, Wargon V, M.R. Pilosof A. Gelation and structural characteristics of incompatible whey proteins/hydroxypropylmethylcellulose mixtures. Food Hydrocoll 2006. [DOI: 10.1016/j.foodhyd.2005.11.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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33
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Laneuville SI, Turgeon SL, Sanchez C, Paquin P. Gelation of native beta-lactoglobulin induced by electrostatic attractive interaction with xanthan gum. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2006; 22:7351-7. [PMID: 16893237 DOI: 10.1021/la060149+] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The mechanism and kinetics of the electrostatic gelation of native beta-lactoglobulin-xanthan gum mixtures in aqueous solution is reported. The total biopolymer concentration at which gelation was obtained was extremely low (0.1 wt %) compared to the usually tested concentrations for protein-polysaccharide mixed gels (4-12 wt %). This is, to our knowledge, the first time that oppositely charged proteins and polysaccharides are reported to form a gel without applying any treatment to denature the protein (e.g. heating, enzymatic hydrolysis) and at such low concentrations. Static light-scattering and viscoelastic measurements allowed determination of the gelation kinetics. It was found that the gelation process initiated following a similar path as that of an associative phase separation process, i.e., with the formation of primary and interpolymeric electrostatic complexes. However, interpolymeric complexes were able to form clusters and junction zones that resulted in the freeze-in of the whole structure at the point of gelation. The formed gel is therefore a coupled-gel, that is, a gel that has junction zones involving two different molecules. The structuration of xanthan gum, even at these low concentrations, may have played a role in the structuration process. Due to the electrostatic nature of the gels, there was an optimum pH and macromolecular ratio at which the stability of the gels was maximal. This was related to the existence of a stoichiometric electrical charge equivalence pH, where molecules carry equal but opposite charges and protein-polysaccharide interactions are at their maximum.
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Affiliation(s)
- Sandra I Laneuville
- Dairy Research Center STELA and Institute of Nutraceuticals and Functional Foods, Faculty of Agriculture and Food Science, Université Laval, Pavillon Paul-Comtois, Québec, Canada G1K-7P4
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Colsenet R, Söderman O, Mariette F. Effects of ionic strength and denaturation time on polyethyleneglycol self-diffusion in whey protein solutions and gels visualized by nuclear magnetic resonance. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2006; 54:5105-12. [PMID: 16819923 DOI: 10.1021/jf060095+] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Pulsed field gradient NMR spectroscopy was used to determine the poly(ethylene glycol) (PEG) self-diffusion coefficient (D(PEG)) as a function of NaCl concentration (C(NaCl)) and denaturation time (t(D)) in whey protein solutions and gels. D(PEG) in the gel decreased with increasing C(NaCl) concentrations and increased with increasing t(D); the increase ceased for all PEGs when the gel was fixed. This increase was more pronounced for the 82250 g/mol PEG than the 1080 g/mol PEG. Moreover, the diffusion coefficient of nonaggregated whey protein was measured and an increase for longer t(D) was also observed. Scanning electron microscopy images and (1)H spectra demonstrated that D(PEG) were related to the structure changes and to the percentage of beta-lactoglobulin denaturation.
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Affiliation(s)
- Roxane Colsenet
- Process Engineering Technology Research Unit, Cemagref, CS 64426, 17 Avenue de Cucillé, 35044 Rennes, Cedex, France
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Monteiro SR, Tavares C, Evtuguin DV, Moreno N, Lopes da Silva JA. Influence of Galactomannans with Different Molecular Weights on the Gelation of Whey Proteins at Neutral pH. Biomacromolecules 2005; 6:3291-9. [PMID: 16283758 DOI: 10.1021/bm050331+] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The effect of locust bean gum, a galactomannan, with different molecular weights on the microstructure and viscoelastic properties of heat-induced whey protein gels has been studied using confocal laser scanning microscopy and small-deformation rheology. The results obtained clearly showed that differences in the molecular weight of the polysaccharide have a significant influence on the gel microstructure. Homogeneous mixtures and phase-separated systems, with dispersed droplet and bicontinuous morphologies, were observed by changing the polysaccharide/protein ratio and/or the molecular weight. At 11% whey protein, below the gelation threshold of the protein alone, the presence of the nongelling polysaccharide induces gelation to occur. At higher protein concentration, the main effect of the polysaccharide was a re-enforcement of the gel. However, at the higher molecular weight and concentration of the nongelling polymer, the protein network starts to lose elastic perfection, probably due to the formation of bicontinuous structures with lower connectivity.
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Affiliation(s)
- Sónia R Monteiro
- Departamento de Química, Universidade de Aveiro, 3810-193 Aveiro, Portugal
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Zhang G, Foegeding EA, Hardin CC. Effect of sulfated polysaccharides on heat-induced structural changes in beta-lactoglobulin. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2004; 52:3975-3981. [PMID: 15186125 DOI: 10.1021/jf035037s] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The mechanism that leads to a decreased aggregation of beta-lactoglobulin in the presence of dextran sulfate and lambda-carrageenan was investigated by assessing changes in the denaturation thermodynamics and protein structure. Differential scanning calorimetry results showed that the denaturation temperature (Tp) was about 4.6 degrees C higher in the presence of dextran sulfate, as compared with beta-lactoglobulin alone, whereas in the presence of lambda-carrageenan the difference in Tp was about 1.2 degrees C. Changes in protein structure studies using near-UV circular dichroism (CD) provided support for the calorimetric results. The transition midpoint (Tm) for denaturation of beta-lactoglobulin was about 5 degrees C higher in the presence of dextran sulfate than that found with beta-lactoglobulin alone and about 2 degrees C in the presence of lambda-carrageenan. Thermal modifications of the tertiary structure of beta-lactoglobulin were irreversible at temperatures above 67 degrees C; the addition of dextran sulfate reduced the extent of such modifications. Far-UV CD studies indicated that the addition of dextran sulfate or lambda-carrageenan did not affect secondary structure changes of beta-lactoglobulin upon heating. These studies indicate that dextran sulfate and lambda-carrageenan can enhance the stability of beta-lactoglobulin and thereby inhibit heat denaturation and aggregation.
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Affiliation(s)
- Guoyan Zhang
- Department of Food Science, North Carolina State University, Raleigh, North Carolina 27695, USA
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