Protein-based strategies for fat replacement: Approaching different protein colloidal types, structured systems and food applications.

In the last decade, food structuring has received considerable attention due to the concern of replacing trans and saturated fats with healthier alternatives without compromising neither technological nor sensorial aspects of food products. Moreover, sustainability topics, consumers' preference for natural ingredients and the molecular architecture displaying a myriad of techno-functionalities embolden the use of proteins. Therefore, a promising approach is to explore this biopolymer as a texture promoter in lipid-based systems, conveying an extra edge in nutritional, sustainable and technological values. A more in-depth comprehension should be cemented to fully harness the potential of proteins in developing soft matter intended for use as fat mimetic. High Internal Phase Emulsion (HIPE), High Internal Phase Pickering Emulsion (HIPPEs), emulgels, oleogels or even bigels can be used in such strategies. Essentially, the formation of such systems relies on the amphiphilic character of proteins. In this sense, the question that arises is how to optimize their solubility in oils to form oil-structured systems? Thus, for oleogel formation the challenge is to overcome the limited dispersibility of proteins in a hydrophobic environment. Therefore, face the growing interest and untapped potential in applying proteins in lipid media, a more wide-ranging picture of their colloidal form (e.g. native, microgels and protein-polysaccharide complexes or conjugates) affecting the structure-function relationship of proteins must be investigated. This review covers different strategies using proteins as building blocks to manufacture different structured systems. Finally, an outlook over the use of protein-based soft matter on an industrial basis is discussed, considering the challenges and perspectives.

Role of the oil on glyceryl monostearate based oleogels.

The high consumption of saturated and trans fats, used in the formulation of lipid-based foods, is associated with incidence of health problems. Organogels or oleogels are a novel class of structured lipids formed from liquid oil as continuous phase entrapped within network of structuring molecules. The aim of this study was to understand the role of oils with different composition on the formation of glyceryl monostearate (GM) gel network. Glyceryl monostearate-based oleogels were produced with the minimal concentration of 5 wt% in sunflower (SF), high oleic sunflower oil (HOS) and coconut oil (CO). The influence of the oil type on the physicochemical properties of the gel was analyzed. The GM gels showed a solid-like behavior using either high oleic sunflower or sunflower oils but did not form a true gel with coconut oil. Although different oils could affect the crystal formation, all gels exhibited needle-like crystal morphology regardless solvent quality. The GM crystals arranged in a lamellar configuration are responsible for entrapping both SF and HOS oils. Degree of saturation of oils might affect GM oleogel properties. Long chain monounsaturated fatty acids favored the packing of GM crystals in a cohesive gel. Furthermore polymorphism with preferential crystalline ß' form of GM was formed using a medium containing one and two unsaturation. In conclusion, it was observed that the type of oil influenced the formation of the GM gel network. These findings allow the better understanding of GM-based oleogels, providing opportunity to design for food products with improved technological and nutritional properties.