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Formation of Calcium‐Mediated Junction Zones at the Onset of the Sol‐Gel Transition of Commercial κ‐Carrageenan Solutions
Author(s) -
Nickerson Michael T.,
Darvesh Rozina,
Paulson Allan T.
Publication year - 2010
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1750-3841.2010.01519.x
Subject(s) - rheometry , carrageenan , polymer , chemistry , calcium , ionic bonding , ion , chemical engineering , crystallography , organic chemistry , biochemistry , engineering
Gelling temperatures of commercial κ‐carrageenan solutions were measured using dynamic oscillatory shear rheometry, in response to varying polymer (0.4% to 1.6%, w/w) and added Ca 2+ (5 to 20 mM) salts. Gelling temperatures were found to shift to higher temperatures with increased polymer and Ca 2+ concentration. The Tang model was used to estimate the number of Ca 2+ ‐mediated cross‐links formed with κ‐carrageenan at the onset of junction zone formation. Based on this model, 6 κ‐carrageenan double helices were estimated to be cross‐linked by 5 Ca 2+ ions through ionic bridging and electrostatic attraction, within a cross‐linking region equivalent to one pitch of the double helix.