Thermal and structural changes of rapeseed oil during isothermal storage at low temperature

Induction Periods for Lipid Crystallization of Various Vegetable Oils

“…We considered the reason for the longer induction period of rapeseed oil at 23 than the period presumed from the periods at other temperatures as follows 16,19 : vegetable oil contains various TAGs with different melting points. At the beginning of isothermal storage, TAGs are in liquid and semi-solid states, and in liquid and solid states at a relatively high and low temperatures, respectively 16 . The rapeseed oil is thought to crystallize through the melt-mediated transition 16,19 .…”

“…At the beginning of isothermal storage, TAGs are in liquid and semi-solid states, and in liquid and solid states at a relatively high and low temperatures, respectively 16 . The rapeseed oil is thought to crystallize through the melt-mediated transition 16,19 . Melt-mediated transition means crystallization in which crystal in an unstable form changes to a melt once and then it transforms into crystal in a more stable form 20,21 .…”

Analysis of Nonisothermal Crystallization of Rapeseed Oil by Deconvolution of Differential Scanning Calorimetry Curve

“…When the peak top temperatures of peaks 1 through 3 were extrapolated to a cooling rate of 0 /min, all the peaks intersected the vertical axis at approximately 30 . However, rapeseed oil crystallized even during isothermal storage at 20 or higher 13,27,28 . These facts suggest that the phenomena occurring at the slow cooling rate were significantly different from those occurring during the isothermal storage.…”

“…Such a temperature dependence was specific to peak 1, and it was not recognized in other peaks. The crystallization behavior of rapeseed oil kept isothermally at 17 or lower was previously investigated 13,27,28 . The induction period for crystallization did not simply shorten as the storage temperature decreased, but it showed a unique behavior of extending at approximately 23 .…”

Crystallization kinetics of safflower and olive oils during low-temperature storage

“…In that study, stress measurement, temperature measurement, and differential scanning calorimetry (DSC) analysis revealed that several hours to half a day were required for complete crystallization during the isothermal storage of rapeseed oil at low temperatures (Miyagawa et al, 2015;Miyagawa et al, 2016). X-ray structural analysis showed minute structural changes during the induction period for crystallization and the crystalline polymorphism after crystallization (Miyagawa et al, 2017). Although these methods are useful for identifying the details of phenomena occurring during the crystallization process, they are not applicable to continuous measurement for the same sample over a long period of time.…”