%0 Journal Article %1 Draget2001 %A Draget, K. I. %A Gaserod, O. %A Aune, I. %A Andersen, P. O. %A Storbakken, B. %A Stokke, B. T. %A Smidsrod, O. %C THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND %D 2001 %I ELSEVIER SCI LTD %J Food Hydrocolloids %K ;; [ISI:] extension %N 4-6 %P 485 -- 490 %T Effects of molecular weight and elastic segment flexibility on syneresis in Ca-alginate gels %V 15 %X Syneresis in Ca-alginate gels was studied as a function of the alginate molecular weight and the degree of flexibility of the elastic segments. Small angle X-ray scattering of alginate gels reveals an increased lateral association of junction zones when entering a Ca2+ regime giving syneresis. This suggests growth of junction zones to be the primary driving force for syneresis. Ca-alginate gels prepared from alginates with different molecular weights show a reduced syneresis with decreasing M-w A reduced syneresis is also observed when fractions of a high M-w alginate is replaced by short alginate molecules enriched in guluronate residues. The effect of altering the monomer sequence of the elastic segments spanning the junction zones was studied by converting poly- mannuronate regions to alternating guluronate/mannuronate sequences by the mannuronan C5-epimerase AlgE4. This epimerisation reaction gives a more flexible elastic segment. The epimerased alginates yielded gels with larger syneresis compared to the non-epimerased, native alginate samples. Thus, both molecular weight and elastic segment flexibility are needed in a molecular model for describing syncretic behaviour in alginate gels. These parameters will to a large extent determine to which degree the non-equilibrium nature of the alginate gel is macroscopically expressed (syneresis). (C) 2001 Elsevier Science Ltd. All rights reserved.

@article{Draget2001, __markedentry = {[phpts:6]}, abstract = {Syneresis in Ca-alginate gels was studied as a function of the alginate molecular weight and the degree of flexibility of the elastic segments. Small angle X-ray scattering of alginate gels reveals an increased lateral association of junction zones when entering a Ca2+ regime giving syneresis. This suggests growth of junction zones to be the primary driving force for syneresis. Ca-alginate gels prepared from alginates with different molecular weights show a reduced syneresis with decreasing M-w A reduced syneresis is also observed when fractions of a high M-w alginate is replaced by short alginate molecules enriched in guluronate residues. The effect of altering the monomer sequence of the elastic segments spanning the junction zones was studied by converting poly- mannuronate regions to alternating guluronate/mannuronate sequences by the mannuronan C5-epimerase AlgE4. This epimerisation reaction gives a more flexible elastic segment. The epimerased alginates yielded gels with larger syneresis compared to the non-epimerased, native alginate samples. Thus, both molecular weight and elastic segment flexibility are needed in a molecular model for describing syncretic behaviour in alginate gels. These parameters will to a large extent determine to which degree the non-equilibrium nature of the alginate gel is macroscopically expressed (syneresis). (C) 2001 Elsevier Science Ltd. All rights reserved.}, added-at = {2011-11-04T13:47:04.000+0100}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, author = {Draget, K. I. and Gaserod, O. and Aune, I. and Andersen, P. O. and Storbakken, B. and Stokke, B. T. and Smidsrod, O.}, authoraddress = {Norwegian Univ Sci & Technol, NTNU, Dept Biotechnol, Norwegian Biopolymer Lab,NOBIPOL, N-7491 Trondheim, Norway. ; Norwegian Univ Sci & Technol, NTNU, Dept Phys, Norwegian Biopolymer Lab,NOBIPOL, N-7491 Trondheim, Norway. ; FMC Biopolymer, N-3002 Drammen, Norway.}, biburl = {https://www.bibsonomy.org/bibtex/24df0d43b68c8fd93314d6bf14df552e5/pawelsikorski}, citedref = {ANDRESEN IL, 1977, ACS SYM SER, V48, P361 ; ANDRESEN IL, 1977, CARBOHYD RES, V58, P271 ; CHRISTENSEN BE, 2000, COMMUNICATION ; DRAGET KI, 1991, CARBOHYD POLYM, V14, P159 ; DRAGET KI, 1997, 9700176, NO ; DRAGET KI, 1998, 9800142, NO ; DRAGET KI, 2000, INT J BIOL MACROMOL, V27, P117 ; DUNSTAN DE, 2000, GUMS STABILIZERS FOO, V10, P137 ; ERTESVAG H, 1996, CARBOHYDR EUR, V14, P14 ; GRASDALEN H, 1983, CARBOHYD RES, V118, P255 ; HAUG A, 1966, ACTA CHEM SCAND, V20, P183 ; HAUG A, 1967, ACTA CHEM SCAND, V21, P691 ; LUCEY JA, 1997, INT DAIRY J, V7, P389 ; MARTINSEN A, 1992, BIOTECHNOL BIOENG, V39, P186 ; MOE S, 1991, CARBOHYD POLYM, V19, P279 ; SKJAKBRAEK G, 1989, CARBOHYD POLYM, V10, P31 ; SMIDSROD O, 1973, CARBOHYD RES, V27, P107 ; SMIDSROD O, 1973, THESIS NORWEGIAN I T ; SMIDSROD O, 1974, J CHEM SOC F1, P263 ; SMIDSROD O, 1996, CARBOHYDR EUR, V14, P6 ; SMIDSROD O, 1996, FOOD COLLOIDS PROTEI, P279 ; STOKKE BT, 1993, CARBOHYD POLYM, V22, P57 ; STOKKE BT, 2000, MACROMOLECULES, V33, P1853 ; VANVLIET T, 1991, COLLOID POLYM SCI, V269, P620}, interhash = {015ae5ed3518c009ee3e0931c85d1614}, intrahash = {4df0d43b68c8fd93314d6bf14df552e5}, isifile-dt = {Article}, isifile-ga = {498KY}, isifile-j9 = {FOOD HYDROCOLLOID}, isifile-nr = {24}, isifile-pi = {OXFORD}, isifile-rp = {Draget, KI, Norwegian Univ Sci & Technol, NTNU, Dept Biotechnol, ; Norwegian Biopolymer Lab,NOBIPOL, N-7491 Trondheim, Norway.}, isifile-sc = {Chemistry, Applied; Food Science & Technology}, isifile-tc = {6}, issn = {0268-005X}, journal = {Food Hydrocolloids}, keywords = {;; [ISI:] extension}, language = {English}, month = {JUL-NOV}, number = {4-6}, owner = {phpts}, pages = {485 -- 490}, publisher = {ELSEVIER SCI LTD}, size = {6 p.}, sourceid = {ISI:000172510000018}, timestamp = {2011-11-04T13:47:09.000+0100}, title = {Effects of molecular weight and elastic segment flexibility on syneresis in Ca-alginate gels}, volume = 15, year = 2001 }