Thermo-Oxidative Stability and Functional Properties of Extra Virgin Olive Oil Oleogels

TL;DR

This study examines how beeswax can be used to create stable olive oil oleogels that resist degradation during heating, offering a potential alternative for food applications.

Contribution

The study demonstrates that beeswax-modified oleogels can partially reduce degradation compounds in olive oil during thermal processing.

Findings

Oleogels showed lower polar compound levels and delayed thermal degradation compared to unstructured olive oil.

Gelation altered oxidation product formation, as indicated by K232 and K270 measurements.

Beeswax incorporation offers a functional alternative for structuring fats in thermal food processes.

Abstract

Structuring oils using oleogels (OGs) represents a promising strategy for developing semi-solid lipid matrices with applications in food and other soft systems. This study evaluated the thermal stability and physicochemical properties of an oleogel (OG) formulated with extra virgin olive oil (EVOO) and beeswax (BW, 6%). The oleogel and olive oil samples were initially characterized by thermogravimetric analysis (TGA/DTG). The beeswax and oleogel samples were initially characterized by texture analysis. An antioxidant capacity (ORAC) analysis was initially applied to the beeswax sample. An initial rheometric analysis was applied to the oleogel sample. Fatty acid profiling and infrared spectroscopy were applied initially and finally to the oleogel and olive oil samples. During the thermal processing (80 °C, 14 days) of the oleogel and olive oil, analyses of the percentage of polar compounds, refractive index, and absorption parameters (K232 and K270) were performed. The oleogel exhibited a soft, pseudoplastic network, with lower hardness and mechanical strength than pure beeswax. Gelation modified the thermo-oxidative stability of EVOO, showing lower levels of polar compounds (from day 7 of heating; p = 0.028) and a slight delay in the onset of thermal degradation (Tonset), suggesting partial protection against the formation of polar degradation compounds. Furthermore, the evolution of K232 indicated differences in the formation of primary oxidation products (p = 0.027) over the 14 days of heating, while K270 showed no differences in the formation of secondary oxidation compounds. This reflects the complex interaction between the gelled matrix and the lipid deterioration mechanisms. Overall, the results demonstrate that the incorporation of beeswax allows for a partial reduction in degradation compounds in high-temperature processes, producing technologically functional oleogels that offer a potential alternative source for structuring solid fats. This work provides relevant evidence for the rational design of oleogels based on unrefined oils and opens new opportunities for their application in food systems and gelled matrices with thermal processing requirements.

Figures