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Effects of Ultrasonic Parameters on the Crystallization Behavior of Palm Oil
Author(s) -
Chen Fangfang,
Zhang Hong,
Sun Xiaoyang,
Wang Xingguo,
Xu Xuebing
Publication year - 2013
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/s11746-013-2243-y
Subject(s) - crystallization , supercooling , materials science , sonication , ultrasonic sensor , palm oil , irradiation , phase (matter) , analytical chemistry (journal) , optical microscope , composite material , chemical engineering , scanning electron microscope , chromatography , chemistry , thermodynamics , physics , food science , organic chemistry , acoustics , nuclear physics , engineering
The crystallization behavior of palm oil (PO) without and with the application of high‐intensity ultrasound (HIU) was investigated as the function of irradiation time (20, 60, 120, and 240 s), ultrasonic intensity (47.5, 95, 270, and 475 W) and temperature (20, 25, 30, and 36 °C). The effects on the crystallization behavior of PO were evaluated by ultraviolet/visible spectrophotometry, pulsed nuclear magnetic resonance and polarized light microscopy. Results indicated that all these parameters affected crystallization behavior. HIU significantly reduced the induction time and accelerated the crystallization rate at operating temperatures above 25 °C, but there was no significant difference at 20 °C due to high supercooling. The effects of HIU were more significant at higher power level and longer irradiation time, however, the thermal effect of ultrasound also increased with longer sonication time. The optimal sonication time was approximately 120 s which accelerated the crystallization rate of PO the most. The morphology studies suggested that HIU changed the growth mechanisms of crystals and generated smaller and uniformly crystals. At 36 °C, with extremely low supercooling condition, a combined effect was observed that prevented the separation of solid phase and liquid phase of the crystallized sample, and then led to a uniform distribution of crystals.