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Mocanu M, Rolin C, Mohammadifar MA, Mohammadi R, Bahrami R. The effect of sodium hexametaphosphate on the efficiency of pectin in stabilizing acidified milk drinks. Food Hydrocoll 2021. [DOI: 10.1016/j.foodhyd.2021.106767] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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2
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Alba K, Kasapis S, Kontogiorgos V. Influence of pH on mechanical relaxations in high solids LM-pectin preparations. Carbohydr Polym 2015; 127:182-8. [PMID: 25965472 DOI: 10.1016/j.carbpol.2015.03.051] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2015] [Revised: 03/12/2015] [Accepted: 03/13/2015] [Indexed: 11/18/2022]
Abstract
The influence of pH on the mechanical relaxation of LM-pectin in the presence of co-solute has been investigated by means of differential scanning calorimetry, ζ-potential measurements and small deformation dynamic oscillation in shear. pH was found to affect the conformational properties of the polyelectrolyte altering its structural behavior. Cooling scans in the vicinity of the glass transition region revealed a remarkable change in the viscoelastic functions as the polyelectrolyte rearranges from extended (neutral pH) to compact conformations (acidic pH). This conformational rearrangement was experimentally observed to result in early vitrification at neutral pH values where dissociation of galacturonic acid residues takes place. Time-temperature superposition of the mechanical shift factors and theoretical modeling utilizing WLF kinetics confirmed the accelerated kinetics of glass transition in the extended pectin conformation at neutral pH. Determination of the relaxation spectra of the samples using spectral analysis of the master curves revealed that the relaxation of macromolecules occurs within ∼ 0.1s regardless of the solvent pH.
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Affiliation(s)
- K Alba
- Department of Biological Sciences, University of Huddersfield, Huddersfield HD1 3DH, UK
| | - S Kasapis
- School of Applied Sciences, RMIT University, City Campus, Melbourne 3001, VIC, Australia
| | - V Kontogiorgos
- Department of Biological Sciences, University of Huddersfield, Huddersfield HD1 3DH, UK.
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Martinez RM, Shimojo AAM, Santana MHA. Rheological properties of citrus pectin dispersions and its blends with polyquaternium-7 and colloidal particles. J Appl Polym Sci 2014. [DOI: 10.1002/app.40583] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Renata Miliani Martinez
- Department of Engineering of Materials and of Bioprocesses; School of Chemical Engineering, University of Campinas (UNICAMP); 13083-970 Campinas São Paulo Brazil
| | - Andréa Arruda Martins Shimojo
- Department of Engineering of Materials and of Bioprocesses; School of Chemical Engineering, University of Campinas (UNICAMP); 13083-970 Campinas São Paulo Brazil
| | - Maria Helena Andrade Santana
- Department of Engineering of Materials and of Bioprocesses; School of Chemical Engineering, University of Campinas (UNICAMP); 13083-970 Campinas São Paulo Brazil
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George P, Lundin L, Kasapis S. Fundamental studies on the structural functionality of whey protein isolate in the presence of small polyhydroxyl compounds as co-solute. Food Chem 2013; 139:420-5. [DOI: 10.1016/j.foodchem.2013.01.032] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2012] [Revised: 11/28/2012] [Accepted: 01/07/2013] [Indexed: 10/27/2022]
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5
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Almrhag O, George P, Bannikova A, Katopo L, Chaudhary D, Kasapis S. Analysis on the effectiveness of co-solute on the network integrity of high methoxy pectin. Food Chem 2012; 135:1455-62. [DOI: 10.1016/j.foodchem.2012.06.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Revised: 05/23/2012] [Accepted: 06/11/2012] [Indexed: 11/27/2022]
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6
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Nickerson MT, Paulson AT, Speers RA. Time-temperature studies of gellan polysaccharide-high sugar mixtures: effect of sodium ions on structure formation. J Food Sci 2007; 72:E315-9. [PMID: 17995732 DOI: 10.1111/j.1750-3841.2007.00388.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Changes to the viscoelastic storage and loss moduli were measured as a function of temperature and oscillatory frequency for 0.5% (w/w) gellan:80% (w/w) cosolute dispersions with added Na(+) (40 to 160 mM). Isothermal frequency (0.15 to 15 Hz) and thermal scans (at 0.15 Hz) were performed over a decreasing then increasing temperature range of 85 to 5 degrees C and 5 to 85 degrees C, respectively. Moduli were found to increase in magnitude with decreasing temperature and increasing levels of Na(+) during cooling, then remained relatively thermally irreversible upon heating. Isothermal frequency (ITF) data were described using the time-temperature superposition (TTS) principle and the modified Cole-Cole (MCC) analysis. Both TTS and the MCC analyses successfully described the behavior of samples containing 40 mM added Na(+) during cooling and heating, and at the 100-mM Na(+) level during cooling. TTS superposed ITF data over the entire temperature range, whereas successful superposition was restricted to lower temperatures in the MCC analysis, where the viscoelastic response was dominated by the long-range relaxation of gellan chains between junction zones. Failure of both analyses was attributed to the formation of junction zones composed of polymer-polymer associations. It is proposed that the addition of Na(+) promotes the formation of a weakly cross-linked gellan network.
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Affiliation(s)
- M T Nickerson
- Dept. of Applied Microbiology and Food Science, Univ. of Saskatchewan, Saskatoon, SK, Canada
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7
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Time–temperature studies of κ-carrageenan gelation in the presence of high levels of co-solutes. Carbohydr Polym 2005. [DOI: 10.1016/j.carbpol.2005.05.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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8
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Al-Marhoobi IM, Kasapis S. Further evidence of the changing nature of biopolymer networks in the presence of sugar. Carbohydr Res 2005; 340:771-4. [PMID: 15721352 DOI: 10.1016/j.carres.2004.12.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2004] [Accepted: 12/03/2004] [Indexed: 11/23/2022]
Abstract
Despite claims made in the literature that polysaccharides maintain a substantially aggregated morphology in the form of "gel particulates" or "gel islands" at a high sugar environment, results of differential scanning calorimetry (DSC) discussed now demonstrate that extensive macromolecular order is not thermodynamically stable. Gelatin, on the other hand, appears to demix from the sugar-rich domains, which promote chain association rather than inhibiting it. DSC evidence is supported by previously published transmission electron microscopy (TEM) work and mechanical analysis.
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Affiliation(s)
- Insaf M Al-Marhoobi
- Department of Food Science and Nutrition, College of Agricultural and Marine Sciences, Sultan Qaboos University, PO Box 34, Al-Khod 123, Oman
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Kasapis S, Al-Marhoobi IM, Mitchell JR. Molecular weight effects on the glass transition of gelatin/cosolute mixtures. Biopolymers 2003; 70:169-85. [PMID: 14517906 DOI: 10.1002/bip.10427] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The structural properties of four gelatin fractions in mixture with sucrose and glucose syrup have been investigated extensively using small deformation dynamic oscillation. The total level of solids was 80%, the number average molecular weight of the protein ranged from 29.2 to 68 kD, and the temperatures were between 60 and -60 degrees C. Remarkably, the nature of the time and temperature dependence on the viscoelastic functions of all samples could be reduced to master curves using horizontal shift factors. The construction of master curves indicates a common mechanism of structure formation, which, in accordance with the synthetic polymer literature, comprises the rubbery zone, glass transition region, and glassy state. Application of Ferry's free-volume formalism and Rouse theory suggests that there is no change in the thermodynamic state of materials during vitrification, with changes in molecular weight simply introducing shifts in the time scale and temperature range of contributions to viscoelasticity. The thermorheological simplicity allowed development of the concept of "rheological" Tg. This was defined as the point between free-volume phenomena of the polymeric backbone occurring in the glass transition region and an energetic barrier to rotation required for local chain rearrangements in the glassy state. Mechanical relaxation and retardation distribution functions were calculated, thus obtaining values for the effective friction coefficient per monomer unit of the protein. It appears that the local friction coefficient is governed by a linear relationship between fractional free volume and the decreasing molecular weight of the protein, which introduces additional voids due to molecular ends.
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Affiliation(s)
- Stefan Kasapis
- Department of Food Science and Nutrition, College of Agricultural and Marine Sciences, Sultan Qaboos University, P.O. Box 34, Al-Khod 123, Sultanate of Oman.
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Kasapis S, Al-Marhoobi IM, Deszczynski M, Mitchell JR, Abeysekera R. Gelatin vs polysaccharide in mixture with sugar. Biomacromolecules 2003; 4:1142-9. [PMID: 12959577 DOI: 10.1021/bm0201237] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The structural behavior of a well-characterized gelatin sample has been revisited to investigate the morphology of its network in the presence of sugar. This was then contrasted with the corresponding properties of the gelling polysaccharides agarose, kappa-carrageenan, and deacylated gellan. Small deformation dynamic oscillation, differential scanning calorimetry in plain and modulated mode, visual observations, and transmission electron microscopy were used to identify the structural characteristics of the biopolymers from the rubbery plateau through the transition region to the glassy state. In contrast to the collapse of the polysaccharide gels at intermediate levels of co-solute, gelatin forms reinforced networks. The drop in polysaccharide network strength is accompanied by a decline in the enthalpy of the coil-to-helix transition, whereas the transition enthalpy is more pronounced in gelatin gels in accordance with their strengthening. Tangible evidence of the molecular transformations was obtained using microscopy, with polysaccharides disaggregating and dissolving in the saturated sugar environment. Gelatin, on the other hand, is visualized in an aggregated form thus producing a phase-separated topology with sugar.
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Affiliation(s)
- Stefan Kasapis
- Department of Food Science & Nutrition, College of Agricultural & Marine Sciences, Sultan Qaboos University, PO Box 34, Al-Khod 123, Sultanate of Oman.
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Shafiur Rahman M, Kasapis S, Guizani N, Saud Al-Amri O. State diagram of tuna meat: freezing curve and glass transition. J FOOD ENG 2003. [DOI: 10.1016/s0260-8774(02)00346-1] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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12
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Deszczynski M, Kasapis S, MacNaughton W, Mitchell JR. High sugar/polysaccharide glasses: resolving the role of water molecules in structure formation. Int J Biol Macromol 2002; 30:279-82. [PMID: 12297236 DOI: 10.1016/s0141-8130(02)00034-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Small-deformation dynamic oscillation and differential scanning calorimetry were used to ascertain the role of water molecules in high sugar/polysaccharide glasses. Increasing replacement of water with sugar affects adversely tahe degree of order in the polysaccharide network to such an extent that at level of solids >90% structure formation is no longer possible. Depending of the polymeric ability to form a network, the rheological T(g) can be up to 30 degrees higher than the calorimetric T(g).
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Affiliation(s)
- Marcin Deszczynski
- Division of Food Sciences, Sutton Bonington Campus, University of Nottingham, LE12 5RD, Loughborough, UK
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Kasapis S, Desbrières J, Al-Marhoobi IM, Rinaudo M. Disentangling alpha from beta mechanical relaxations in the rubber-to-glass transition of high-sugar-chitosan mixtures. Carbohydr Res 2002; 337:595-605. [PMID: 11909592 DOI: 10.1016/s0008-6215(02)00020-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The occurrence of molecular motions in addition to those of the glass-transition region (alpha mechanism) were investigated in chitosan and a branched derivative substituted with alkyl chains having eight carbon atoms. Once hydrophobic interactions of the alkyl groups in aqueous solution were demonstrated, polymers were mixed with glucose syrup at high levels of solids. The real (G') and imaginary (G") components of the complex dynamic modulus in high-solid mixtures were measured between 0.1 and 100 rad s(-1) in the temperature range from -55 to 50 degrees C. The method of reduced variables gave superposed curves of G' and G", which unveiled an anomaly in the dispersion of the alkylated derivative both in terms of higher modulus values and dominant elastic component of the polymeric network, as compared with the glass-transition region of chitosan. It was proposed that the new mechanical feature was due to beta mechanism, and master curves of viscoelastic functions and relaxation processes were constructed to rationalize it.
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Affiliation(s)
- Stefan Kasapis
- Department of Food Science and Nutrition, College of Agriculture, Sultan Qaboos University, PO Box 34, Al-Khod 123, Sultanate of Oman.
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Kasapis S, Al-Marhobi IM, Sworn G. Alpha and beta mechanical dispersions in high sugar/acyl gellan mixtures. Int J Biol Macromol 2001; 29:151-60. [PMID: 11589967 DOI: 10.1016/s0141-8130(01)00156-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The real (G') and imaginary (G") components of the complex modulus have been measured between 0.1 and 100 rad/s in the temperature range of 70--55 degrees C for a mixture of 1% high acyl gellan with 79% glucose syrup, and 79% glucose syrup. The method of reduced variables gave superposed curves of G' and G" as a function of timescale of measurement, which matched the thermal profiles of shear modulus obtained by scanning at the constant rate of 1 degrees C/min. Data of the gellan/co-solute mixture could be analysed in terms of two distinct mechanisms. For the alpha dispersion, G' and G" superposed with the horizontal reduction factor a(T) whose temperature dependence followed an equation of the Williams-Landel-Ferry form. Mechanical spectra of the beta dispersion also superposed with the factor a(T) whose temperature dependence, however, corresponded to a constant energy of activation. Relaxation spectra have been calculated for both dispersions. Those for the alpha mechanism were attributed to the chain backbone motions and the friction coefficient per tetrasaccharide repeat unit in backbone motion was calculated from the extended Rouse theory. When the contribution of the solvent alone was studied, no spectra for the beta dispersion were observed supporting the hypothesis of the dispersion being attributed to the side-chain motions of the acyl groups. The spectra of the beta mechanism were relatively broader than for the alpha dispersion. The relative location of the beta dispersion on the time scale or temperature range was found to be between the alpha dispersion (glass transition region) and the glassy state.
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Affiliation(s)
- S Kasapis
- Department of Food Science and Nutrition, College of Agriculture, Sultan Qaboos University, PO Box 34, Al-Khod 123, Oman.
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15
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Kasapis S. Advanced topics in the application of the WLF/free volume theory to high sugar/biopolymer mixtures: a review. Food Hydrocoll 2001. [DOI: 10.1016/s0268-005x(01)00048-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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