The Effects of Emulsifier Addition on the Functionalization of a High-Oleic Palm Oil-Based Oleogel

Abstract

Alternatives to oils with high saturated fatty acid content are often liquid oils (high in unsaturated fatty acids) that have a modified structure created either through additives or processing. Emulsifiers are additives that can be used as structuring agents of liquid fats; this process results in products such as oleogels, which can broaden the applications of these oils. This study assessed and compared the effects of mono- and diglycerides at 3%, 5%, 7% and 10% w/w on the mechanical and thermal properties of high-oleic palm oil (HOPO) oleogels. HOPO was heated to 75 °C and mixed with mono- or diglycerides at those four concentrations. The thermomechanical properties of the melted oleogels were assessed using differential scanning calorimetry (DSC). The melted oleogels were cooled to final temperatures of 5 °C, 10 °C and 15 °C under identical cooling rates, after which a puncture test (via a texture analyzer) was used to assess their textures. Finally, polarized light microscopy was used to assess the mechanical changes induced through emulsifier addition. The results showed that the use of mono- and diglycerides significantly modified the thermal and mechanical properties of the oleogels. The addition of saturated monoglycerides promoted a higher-temperature nucleation stage that did not previously occur in HOPO. The onset crystallization temperature increased with the addition of diglycerides, promoting crystallization at higher temperatures of the high-melting fraction of HOPO. The hardness of the oleogel generally increased with emulsifier addition and a reduction of the temperature. The effect of the temperature on the hardness was significantly greater in the diglyceride oleogel than in the monoglyceride oleogel. This study shows that the addition of mono- and diglycerides allows companies to customize their formulations to achieve desired results that may not previously have been possible, thereby facilitating novel uses for these oils within the industry.

Thermomechanical Properties of High Oleic Palm Oil Assessed Using Differential Scanning Calorimetry, Texture Analysis, Microscopy, and Shear Rheology

“…These results were consistent with the findings of Mozzon et al [12], who also showed that 'hybrid palm oil' had an oleic acid content higher than crude palm oil. The thermal transitions are aligned with results for HOPO in [8,25]. Based on the onset temperature and peak crystallization points observed in both oils, the mechanical, rheological, and visual characteristics were tested at 20 While most of the work in this study focused on temperatures above 0 °C (in the common range of food industry applications), the first large melting peak for HOPO had an onset of −5.45 °C which ends at 3.5 °C, while for SPO, the peak extends up to 10 °C.…”

“…Currently, there is limited knowledge on the crystallization kinetics and physical properties of HOPO and its products [24]. Publications have addressed the use of HOPO in oleogel formulations using mono and diglycerides [25] and some of these oleogels perform identically to SPO oleogels in the baking of cookies [26]. However, a general characterization of HOPO is needed to understand this oil as an ingredient and enable the expansion of its use to multiple applications.…”