Organogelation is one of the most promising techniques to replace unhealthy saturated fats in foods, guaranteeing a similar texture but with the use of healthy unsaturated oils. Nevertheless, the number of food grade gelators is not high, and the discovery of new agents is still due to "serendipity". Among the different gelators investigated in the literature, fatty alcohols, i.e., aliphatic hydrocarbons with a hydroxyl group, represent an interesting alternative. Within this context, a mixture of long chain alcohols, commercially known as Policosanol, seems particularly promising. Policosanol can be extracted from natural sources such as sugarcane, beeswax, wheat germ, and rice bran. Policosanol is very effective in structuring edible oils even at a very low concentration (0.1%) and has positive health effects on the cardio-circulatory system and cholesterol levels. Therefore, structured vegetable oils can be obtained through the use of edible healthy gelators (i.e., Policosanol). The oleogels developed with Policosanol might be used as substitutes for traditional hard fats or as novel structured vegetable oil systems with controlled rheological properties. The rheological, microscopic, and sensory properties of fatty alcohol oleogels are discussed in this chapter, as well as their potential use for producing new foods and vehicles for the controlled release of nutraceutical compounds.

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Background: Polymeric gels, an important class of soft matter systems, are widely used for commercial applications particularly in food products (i.e., saturated fat replacement). The efficiency of the product for a particular application can be directly linked to its rheological signature. However, the rheological imprint of these structured systems is significantly dependent on the interactions between their individual components. Therefore, the rational understanding of interacting components, their structural arrangements and the resultant characteristics of a hybrid system is vital, in order to speed-up our progress in recognizing the suitable combination of gelling agents and also to tune the technological and functional properties of final product. Scope and approach: The main aim of this narrative review article is to look at the synergistic interactions (i.e., interpenetrating polymer structures) between different components of the hybrid systems (i.e., multi-component organogels or bigels), in order to unveil the resultant rheological characteristics for different commercial applications including food systems. However, multi-component hydrogel systems have not been discussed in this review. Key findings and conclusions: The existence of synergistic interactions between different gelators in multi-component organogels (i.e., higher values of hardness and moduli (G^'and G'^') of multi-component organogel than the corresponding mono-component system) is clearly evident from the literature. This synergy also helps in optimizing the rheological signature of final system by exploiting the concept of formulation engineering. However, this exciting concept of synergistic enhancement in properties has not yet been explored in the field of bigels. The incorporation of colloidal particles in the gelled system resulted in increased stability and higher moduli values, as compared to the gels without particles. This exciting approach can also be quite useful for designing food products by exploiting the useful properties of gelators and (nano)particles, in a single system.

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Bigels are interesting semisolid formulations with better properties for different applications such as cosmetics and pharmaceutical systems. Due to the mixing of two phases of different nature (polar and apolar), bigels possess some interesting features like ability to deliver hydrophilic and hydrophobic drugs, better spreadability and water washability, improved permeability of drugs, enhanced hydration of stratum corneum and ability to manipulate the drug release rate. The main objective of this review article is to provide a thorough insight into the important characteristics of bigels together with the discussion on modelling of bigel systems to relate their properties with individual constituents and different parameters. Moreover, some important applications of bigels are also discussed by considering some examples from the literature.@en