Microstructuring Process in Oleogels Formulated with Vegetable Oils and
Monoglycerides: A Comparison of Non-Isothermal Nucleation Kinetics by
Spectrophotometric and DSC Analysis
Abstract
The initial oleogelation process (microstructuring) as well as the
formulation are determinant to obtain the desired characteristics in
oleogels with potential application in the industry. The
microstructuring process in oleogels has been extensively studied by
means of techniques highly sensitive to thermal variations, such as
differential scanning calorimetry (DSC). However, there are other
readily available techniques and equipment that can be employed to
perform similar evaluations. Non-isothermal nucleation kinetics by
spectrophotometric methods can be used as alternatives to basic
crystallization studies in oleogels. Therefore, in this research a
comparison of both techniques is presented, highlighting their
similarities, advantages and limitations, in the study of the
microstructure of oleogels. Oleogels were obtained with a minimum
concentration of gelator and another saturated one, using vegetable oils
of different degrees of saturation. The crystallization profiles of the
oleogels were obtained by DSC, a non-isothermal nucleation kinetics was
performed from the molten system and the final microstructure was
evaluated by optical microscopy. The Fisher-Turnbull and Avrami model
was used to evaluate the behavior during microstructuring. A gap was
observed during the crystallization process by DSC which can be
evaluated by spectrophotometry. Differences in the microstructuring
process were found in both methods due to the temperature ramp used and
formulation variables. The results obtained by spectrophotometry
indicate that it can be a good alternative, easily accessible in oleogel
crystallization studies, when high sensitivity or very specific thermal
parameters are not required.