Oleogelation: From Scientific Feasibility to Applicability in Food Products

Abstract

Oleogels offer the possibility to replace conventional saturated fatty acid (SAFA)-based lipids with a healthier alternative by immobilizing liquid edible oils in a 3D-network which is provided by an oleogelator. Numerous molecules which can structure oils rich in (poly)unsaturated fatty acids have been identified. These differ greatly in their chemical composition, network formation, and interactions and thus macroscopic properties of the respective oleogels. Oleogels have been a focal point of food research for over 20 years, yet product applications are lacking. Hence, the question arises whether the application of oleogels is unfeasible or if science lost sight of its objective. This review aims to assess different structuring systems concerning their availability, their potential for the utilization in food products and, if possible, their prices. Moreover, recent studies comprising the application of oleogels in food products are reviewed with special emphasis on the state and the function of the lipid phase during processing and in the final product. Therefore, the physical properties and preparation methods of different oleogels need to be considered in connection with the respective food application. Finally, it is discussed whether the application of oleogels is justified in these products and advantageous in comparison to liquid oil. Practical Applications: A diet rich in mono-and polyunsaturated fatty acids which make up the majority of liquid edible oils lowers the risk to suffer from cardiovascular diseases. Unfortunately, these oils cannot provide texture to food products in their native state. Oleogelation has the potential to deliver the solid structure necessary for numerous food products by transferring an oil rich in essential fatty acids into a solid-like structure. Besides, the nutritional value of these oils remains practically unchanged. Although oleogelation has been the objective of various research groups for more than 20 years, product applications are scarce. This review aims to stimulate the mindfulness of research concerning the successful application of oleogels in food products. This hopefully enables a better connection between science and industry.

Oleogels—Their Applicability and Methods of Characterization

“…The different routes to structure the lipid phases have been discussed in depth elsewhere [ 8 , 14 , 15 , 16 , 17 , 20 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 ]. There are several attempts to categorize the different structuring systems.…”

“…The split between solid and liquid phases can vary greatly depending on the application at hand. It should be pointed out that the nature of primary crystals, their mutual interaction, and the structure build-up from crystal agglomerates can considerably be influenced by the selection of the molecular TAG composition and processing conditions and the presence of other materials [ 3 , 5 , 6 , 7 , 8 , 9 ]. Obviously, the variation of these parameters allows altering the potential of the three-dimensional network to immobilize oil.…”

“…The increased consumption of these fatty acids (SaFA) has been discouraged for reasons of cardiovascular health. How far the health benefit assigned to the substitution of saturated fatty acids by polyunsaturated fatty acids (PuFA) is based on the reduction of the one or increase of the other shall be irrelevant here [ 8 , 10 , 11 , 12 ]. Beyond these nutritional concerns, there is further motivation to disembark from triglyceride crystal structured lipid phases.…”

“…Numerous organizations, to name a few, the Round Table for Sustainable Palm Oil (RSPO), the Malaysian Palm Oil Board (MPOB), Forum Nachhaltiges Palmöl (FONAP), and Non-governmental organisations such as the World Wildlife Fund (WWF), made efforts to improve the sustainability of palm oil. For example, the position of consumers in Europe toward palm oil remains at least controversial [ 8 , 13 ]. The consumer’s position has resulted in an increasing demand for healthy, organic, sustainable, and regional food products.…”

“…Even though this contribution discusses the applicability of oleogels in foods, the aim is not to generate another general review of the area. Next to the reviews of the past years [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ], just the year 2020 has seen more than nine reviews discussing oleogels related to foods [ 8 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 ]. During this period, also more than 700 original publications relating to oleogels and food have been published.…”