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Development of a rheological method to characterize palm oil crystallizing under shear
Author(s) -
De Graef Veerle,
Goderis Bart,
Van Puyvelde Peter,
Foubert Imogen,
Dewettinck Koen
Publication year - 2008
Publication title -
european journal of lipid science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.614
H-Index - 94
eISSN - 1438-9312
pISSN - 1438-7697
DOI - 10.1002/ejlt.200700315
Subject(s) - shearing (physics) , rheology , shear (geology) , materials science , crystallization , shear modulus , isothermal process , shear rate , composite material , palm oil , phase angle (astronomy) , thermodynamics , optics , chemistry , physics , food science
To follow palm oil crystallization under shear, a new rheological method was developed. This method can be split up into two parts: In the first part, continuous shear is applied for a pre‐defined period and crystallization is monitored by measuring the apparent viscosity as a function of isothermal time under shear. In the second part, shear is halted and oscillation is applied during 30 s, thus recording moduli and phase angle. These moduli and phase angle are then characteristic of a sample crystallized under shear during this pre‐defined period. After repeating this procedure for increasing shearing periods in the first part, complex modulus and phase angle were plotted as a function of isothermal time under shear. The thus obtained results were compared with crystallization data obtained via time‐resolved X‐ray diffraction and polarized light microscopy.