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The effect of supercooling on crystallization of cocoa butter‐vegetable oil blends
Author(s) -
PérezMartínez David,
AlvarezSalas C.,
MoralesRueda J. A.,
ToroVazquez J. F.,
CharóAlonso M.,
DibildoxAlvarado E.
Publication year - 2005
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/s11746-005-1096-z
Subject(s) - supercooling , crystallization , materials science , soybean oil , canola , thermodynamics , chemistry , food science , physics
The solid fat content (SFC), Avrami index ( n ), crystallization rate ( z ), fractal dimension ( D ), and the pre‐exponential term [log(γ)] were determined in blends of cocoa butter (CB) with canola oil or soybean oil crystallized at temperatures ( T Cr ) between 9.5 and 13.5°C. The relationship of these parameters with the elasticity ( G′ ) and yield stress (σ * ) values of the crystallized blends was investigated, considering the equilibrium melting temperature ( T M o ) and the supercooling (i.e., T Cr o − T M o ) present in the blends. In general, supercooling was higher in the CB/soybean oil blend [ T M o =65.8°C (±3.0°C)] than in the CB/canola oil blend [ T M o =33.7°C (±4.9°C)]. Therefore, under similar T Cr values, higher SFC and z values ( P <0.05) were obtained with the CB/soybean oil blend. However, independent of T Cr TAG followed a spherulitic crystal growth mechanism in both blends. Supercooling calculated with melting temperatures from DSC thermograms explained the SFC and z behavior just within each blend. However, supercooling calculated with T M o explained both the SFC and z behavior within each blend and between the blends. Thus, independent of the blend used, SFC described the behavior of G ′ eq and σ * and pointed out the presence of two supercooling regions. In the lower supercooling region, G ′ eq and σ * decreased as SFC increased between 20 and 23%. In this region, the crystal network structures were formed by a mixture of small β′ crystals and large β crystals. In contrast, in the higher supercooling region (24 to 27% SFC), G ′ eq and σ * had a direct relationship with SFC, and the crystal network structure was formed mainly by small β′ crystals. However, we could not find a particular relationship that described the overall behavior of G ′ eq and σ * as a function of D and independent of the system investigated.