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Crystallization behavior of hydrogenated sunflowerseed oil: Kinetics and polymorphism
Author(s) -
Herrera M. L.
Publication year - 1994
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/bf02540547
Subject(s) - crystallization , differential scanning calorimetry , endotherm , polymorphism (computer science) , kinetics , isothermal process , materials science , crystallography , thermodynamics , analytical chemistry (journal) , induction period , chemistry , chemical engineering , chromatography , organic chemistry , biochemistry , physics , quantum mechanics , gene , genotype , engineering
Kinetics of crystallization of hydrogenated sunflowerseed oil was studied by means of an optical method. Two different aspects were examined: the effects of preheating of the molten liquid on induction time of isothermal crystallization and the effects of cooling rate on the crystallization behavior. Induction time for crystallization was markedly dependent on the crystallization temperature and the cooling rate selected. Morphology, polymorphism and chemical composition of the crystals were examined. At all crystallization temperatures, β′‐form was found for the first occurring crystals. Long spacings were also similar in all cases and corresponded to a double chainlength arrangement. The chemical composition of the crystals showed no differences at either cooling rate. However, the melting behavior was different. At a slow cooling rate, fractionation occurred, and differential scanning calorimetry diagrams had a broad second endotherm with three peaks, none of which were completely resolved. The polymorphic transformation rate from β′ to β was slower when induction times were longer.