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Freeze–thaw gelation of hen's egg yolk low density lipoprotein
Author(s) -
Kamat Virendra,
Graham Gillian,
Barratt Martin,
Stubbs Morris
Publication year - 1976
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740271005
Subject(s) - chemistry , differential scanning calorimetry , yolk , chromatography , phospholipid , crystallography , chemical engineering , membrane , biochemistry , food science , physics , thermodynamics , engineering
The freeze–thaw gelation of hen's egg yolk low density lipoprotein (l.d.l.) has been examined by viscometry, agarose gel filtration, electron spin resonance spectroscopy, electron microscopy and differential scanning calorimetry. The data indicate that the core lipids, the hydrocarbon chains of interfacial lipids of l.d.l. and the sulphydryl, imino, amino and tyrosine groups in the side chains of l.d.l. peptides are not directly involved in the gelation mechanisms. The gelation is caused by non‐specific aggregation due to cross‐linking of peptides and/or phospholipid polar head groups of adjacent l.d.l. particles. During freezing, interparticle contacts are formed and strengthened as transformation of solvent water into ice increases the concentration of the particles. Salt and sugar additives inhibit large increases in concentrations of l.d.l. during freezing and prevent gelation by helping to increase solvation of interfacial regions of the l.d.l. particles. Agents that induce large viscosity increases in the l.d.l. sols before freezing may act by producing a local conformational change in l.d.l. protein and/or disrupting lipid–protein bonds.