Candelilla wax‐based oleogels versus palm oil: evaluation of physical properties of innovative and conventional lipids using optical techniques

Abstract

BACKGROUND: The widespread use of palm oil in food production affects high consumption of long-chain saturated fatty acids, which increases the risk of cardiovascular disease. Solid or semi-solid wax-based oleogels obtained as a result of edible oils structuring can be an alternative.RESULTS: Oleogels, obtained by structuring a mixture of refined rapeseed and linseed oils (1:1) with 30-80 g kg −1 candelilla wax (CW), were investigated using optical techniques: multi-speckle diffusing wave spectroscopy, centrifugal stability analysis, reflection method, and polarized light microscopy. Refined palm oil was a comparative sample. Increasing CW concentration resulted in an increase in values of L * parameter and opacity, a decrease in the Yellowness Index and a slight increase in the average crystal size. The microstructure of oleogels with 30 or 40 g kg −1 CW was least like the crystal network. Solidification of oleogels took place in two stages. Increase in CW concentration shortened solidification time and increased solidification temperature (greater elasticity of oleogels). Palm oil solidified the longest (497.1 min) and at the lowest temperature (29.3 °C). It showed lower resistance to centrifugal force than oleogels at 20 and 30 °C. All oleogels were stable (no oil release occurred) at 20 °C.CONCLUSION: Optical methods allow for an objective and detailed analysis of physical properties of palm oil and oleogels, as well as identification and tracking changes at the microstructural level over time. It has great potential in the edible lipid quality control at various stages of processing or storage.

A Study of the Quantitative Relationship between Yield Strength and Crystal Size Distribution of Beeswax Oleogels

“…For example, it was shown that increasing the cooling rate positively affects the oleogel firmness. Similar changes are also observed for the oleogel microstructure, particularly in decreasing the crystal size [ 7 , 8 , 9 , 10 ]. Despite a considerable number of articles on the study of the structure and physical properties of oleogels, there is still no common physically substantiated understanding of the relationship between structure and properties of wax-based oleogels.…”

“…A positive linear relationship between 1/ and 1/ observed for the BW oleogel ( Figure 3 a) is an expected outcome that might be observed for other systems [ 16 ]. Also, the same trend is expected for wax-based oleogels, since the smaller their crystals are in size, the more homogeneous they are distributed [ 8 ]. However, as shown in Figure 3 b, this relationship is still linear but negative for the BWH oleogel.…”

Analysis of Stability, Rheological and Structural Properties of Oleogels Obtained from Peanut Oil Structured with Yellow Beeswax

“…Analysis of microscopic images of crystals developed in oleogels allows for preliminary detection and identification of oleogelators [ 20 ]. Another optical technique which measures light transmission and scattering by the sample provides important information on microrheological properties of the tested samples [ 21 ]. Usually, the rheological test makes measurements on the macroscopic scale and damages samples.…”

“…The MS-DWS method tracks changes in particle motion under the influence of thermal energy in real time (through dynamic light scattering). The advantage of the passive optical microrheology technique is its low invasiveness, and the same sample can be again used for analysis [ 21 , 22 , 23 ].…”

“…In the MS-DWS method, microrheological parameters are calculated based on the mean square displacement of a particle at different frequencies as a function of time [ 24 , 25 ]. Usually, this technique is used for emulsion and hydrogel analysis [ 21 , 23 , 25 ]; however, application of this method to study oleogels is a novel way of characterizing these lipid systems. The aim of this study was to analyze the macro- and microscopic properties of oleogels with yellow beeswax at concentrations of 2, 4, 6 and 8% using known methods and modern optical techniques.…”