Structuring PUFA-rich oils with monoglycerides: Physicochemical and nutritional properties of fat substitutes with high-lipid quality

Abstract

Driven by the demand for semisolid lipid materials with low saturated fatty acid (SFA) content and high-nutritional profiles, monoglyceride (MG) oleogels were produced using oils rich in polyunsaturated fatty acids (PUFA), i.e. fatty acids that are themselves bioactive compounds. The effects of the MG concentration (6% and 10%, w/w) and oil type—sunflower, chia, flaxseed, soybean, and sesame—on nutritional and structural, rheological, mechanical, and thermal properties of oleogels were investigated. Overall, all oleogels were structurally stable gels with textural characteristics that can mimic the functionality of spreadable margarines. In addition, by changing the oil type and MG concentration, the properties studied could be tailored. Particularly, chia and flaxseed oleogels, exhibiting superior nutritional quality based on their low atherogenic and thrombogenic indexes and higher PUFA/SFA ratios, showed the highest hardness (up to 48% higher) and oil binding capacity (OBC). This enhanced functionality was attributed to their microstructural characteristics, featuring smaller crystals, and the unrefined nature of these oils. Notably, flaxseed oleogels with 6% MG yielded OBC values of 99.5%, similar to all samples containing 10% MG. Furthermore, results from a low-temperature Rancimat test suggested that MG crystalline structure may protect chia oil against oxidation. Our findings indicate that PUFA-rich oils have potential for developing health-conscious ingredients with acceptable technological characteristics.