Food grade polymers for the gelation of edible oils envisioning food applications

Abstract

Oleogels are systems traditionally produced by the self-assembly of materials called gelators, which are responsible for inducing viscosity and solid-like capabilities to oil-based systems. The emergent interest concerning oil structuring strategies in food applications is related to oleogels’ capacity to undergo structural and textural tailoring, and the possibility of their use in delivery of bioactive compounds. The selection of the materials and the methodology used to produce oleogels are definitely the key aspects in this kind of systems. The existing, obligatory demand of using food grade ingredients, combined with the increasing requirements for bio-based solutions towards the total replacement of petroleum-based materials narrows the possibilities to a few set of materials. Overall, with the exception of ethylcellulose, a linear polysaccharide derived from cellulose with high hydrophobicity and semi-crystalline nature, polymeric gelators with ability to structure oil are scarce. It is known that the hydrophilic nature of biopolymers does not make them the first choice for oil structuring purposes. Despite of that, some biopolymers are amphiphilic and can interact with apolar phases; this seems to be the case of some polysaccharides and protein combinations (e.g. xanthan gum, gelatin, whey protein and chitin). This chapter will emphasize food grade polymeric gelators with the capacity of oil structuring, using different methodologies. Mainly polysaccharides and proteins able to produce oleogels will be presented, and their distinct chemical structures will be related to their gelation capacity and final oleogel properties. Besides, different structuring methodologies and gelator combinations able to produce oleogels will also be addressed, together with the main advantages and drawbacks of the different methodologies. Finally, the main food applications will be showed, discussing their possible exploitation by the food industry.