Application of Temperature Modulated Optical Refractometry for the Characterization of the Crystallization Behavior of Palm Oil

Abstract
The phase behavior of fats is mainly determined using DSC. Here, the application of temperature modulated optical refractometry (TMOR) was examined to monitor the phase transitions of palm oil with different degrees of saturation.Studying the phase behavior by both methods revealed systematic differences. At identical scan rates, TMOR yielded up to 2 °C higher crystallization temperatures and identified consistently lower temperatures for melting phenomena. Because the prism serves as heating surface and defines the sample volume considered for the measurement a more direct heat transfer with TMOR is assumed. The sample depth above the prism relevant for the determination is only one micron. Hence, a direct heat transfer is ensured and thermal lag is practically eliminated causing the above‐mentioned differences.Because the TMOR signal is averaged over a defined prism surface area data for inhomogeneous samples can be generated. Although actual values for thermal expansion coefficients appear meaningless the combination of the TMOR signals allows to accurately determine the relevant phase transitions. The identification of different polymorphic forms and levels of solids in palm oil will be studied prospectively building on the promising results reported to identify if TMOR can become a valuable extension of the fat technologists’ toolbox.Practical applications: The new temperature modulated optical refractometry could extend the mainly used differential scannin...

Source: European Journal of Lipid Science and Technology - February 1, 2018 Category: Lipidology Authors: Michaela H äupler, Ratna Ayu Savitri, Valeska Hutschenreuter, Eckhard Flöter Tags: Research Article Source Type: research