Department of Food Engineering and Technology, School of Food Engineering, University of Campinas (UNICAMP), 13083-862 Campinas, SP, Brazil.
International Iberian Nanotechnology Laboratory, Av. Mestre José Veiga, 4715-330 Braga, Portugal.
Food Res Int. 2024 Dec;197(Pt 1):115181. doi: 10.1016/j.foodres.2024.115181. Epub 2024 Oct 5.
Oleogels are semi-solid systems that can function both as replacers of trans and saturated fats and/or as carriers of lipophilic bioactive compounds. However, bioactive compounds can affect the structure of the oleogel matrix and this effect depends on the properties of such compounds. Therefore, the aim of this study was to develop oleogels loaded with β-carotene (BC) or resveratrol (R), with low concentrations of glycerol monostearate (GMS, 2-5 wt%) and sunflower oil as organic solvent. The gels were characterized by polarized light microscopy, rheological measurements, differential scanning calorimetry, oil binding capacity and Fourier transform infrared spectroscopy. At higher GMS concentrations, stronger oleogels and higher temperatures associated with transitions (sol-gel/gel-sol and crystallization/melting) were observed. The incorporation of bioactive compounds modified the gelation behavior. BC weakened the oleogel structure during the transient molecular organization of GMS, whereas R increased the dynamic moduli. BC also caused slight oil release at lower concentrations, while R improved retention. The high hydrophobicity of BC may be disturbing the solubility balance of the system, while R has phenolic hydroxyl groups that may strengthen hydrogen bonds. However, there were no considerable changes in mechanical properties after storage. We hypothesize that the molecular organization of GMS over time may be masking the modifications that bioactive compounds cause in mechanical properties. In fact, changes in the structure were revealed, as the addition of BC or R changed the morphology of the three-dimensional network crystals. Thus, the results can contribute to the rational choice of system components using low concentrations of oleogelator, as the composition of the bioactive compound exerts influence on the modulation of lipid matrices.
油凝胶是半固态系统，既可以作为反式脂肪和饱和脂肪的替代品，也可以作为脂溶性生物活性化合物的载体。然而，生物活性化合物可能会影响油凝胶基质的结构，这种影响取决于这些化合物的性质。因此，本研究的目的是开发负载β-胡萝卜素（BC）或白藜芦醇（R）的油凝胶，甘油单硬脂酸酯（GMS，2-5wt%）和葵花籽油作为有机溶剂的浓度较低。通过偏光显微镜、流变学测量、差示扫描量热法、油结合能力和傅里叶变换红外光谱对凝胶进行了表征。在较高的 GMS 浓度下，观察到更强的油凝胶和与转变相关的更高温度（溶胶-凝胶/凝胶-溶胶和结晶/熔化）。生物活性化合物的掺入改变了凝胶化行为。BC 在 GMS 的瞬态分子组织过程中削弱了油凝胶结构，而 R 增加了动态模量。BC 还在较低浓度下导致轻微的油释放，而 R 则提高了保留率。BC 的高疏水性可能会破坏系统的溶解度平衡，而 R 具有酚羟基，可能会增强氢键。然而，在储存后，机械性能没有明显变化。我们假设，随着时间的推移，GMS 的分子组织可能掩盖了生物活性化合物对机械性能造成的改变。事实上，随着 BC 或 R 的添加改变了三维网络晶体的形态，结构的变化被揭示出来。因此，这些结果可以为使用低浓度油凝胶形成剂进行系统成分的合理选择提供参考，因为生物活性化合物的组成会影响脂质基质的调制。
