Oil organogels: the fat of the future? (original) (raw)
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Food Research International, 2009
Numerous foods acquire their elastic properties (i.e., snap, mouth-feel, and hardness) from the colloidal fat crystal network comprised primarily of trans-and saturated fats. These hardstock fats contribute, along with numerous other factors, to the global epidemics related to metabolic syndrome and cardiovascular disease. A dire need for new technologies capable of structuring unsaturated edible oils, reducing the necessity for trans-and saturated fats, are required. At present, organogels are under-utilized in the food industry but numerous potential organogelators exist including: phytosterols and oryzanols, ceramides, monoglycerides and waxes. When examining these compounds as suitable ingredients for the food industry, they should be food grade, cost effective, have no negative health implications and one should be able to modify their physical properties. This review considers alternatives to colloidal fat crystal networks when structuring unsaturated oils as well as methods to modify their physical properties.
Biomimicry – An approach to engineering oils into solid fats
Lipid Technology
The ability to eliminate trans fats, without incorporating additional saturated fats, is limited by the physico‐chemical properties of the processed food and what role the lipids play in the food structure. To maintain the levels of cardio‐protective unsaturated fats alternative methods to structure them are desperately needed. One such strategy is to utilize oleogels or molecular gels comprised of small molecules. Herein, we illustrate the potential of biomimicking the assemblies formed by the intercellular lipids in stratum corneum using stearic acid, ceramide III and replacing cholesterol with β‐sitosterol.
Structure and functionality of edible fats
Soft Matter, 2012
Fat-structured food materials are an important component of our diet. The role that fat plays in material functionality, flavor perception, texture and health characteristics is due in large part to its physical properties. An understanding of these physical properties is relevant from scientific, technological and medical perspectives. The physical properties of fat materials, are, in turn, governed by a complex confluence of the various structural levels in a fat material beginning with triglyceride molecules. The formation of nanoscale structural elements by these molecules is the first step in the formation of a fat material as we know it. This review shows how these microstructural elements can be imaged and characterized. It is also shown that the formation of these nanocrystals is affected by the attendant crystallization parameters. Through simulation and a discussion of van der Waals forces, it is shown that these nanoscale elements assemble into colloidal aggregates with fractal character. The influence of microstructure on the mechanical properties of a fat material is explained using a variety of mechanical models. Lastly, this review examines methods by which the properties and characteristics of the various structural levels can be engineered. Shear has been shown to affect the polymorphism and phase transition kinetics of triglyceride crystals. As well, shear has been shown to modify the aggregation of nanocrystals, with consequences for the porosity and diffusivity of oil through the fat crystal network.
Potential food applications of edible oil organogels
Trends in Food Science & Technology, 2009
The unique physical, functional, and nutritional properties of edible oil organogels has caught the eye of the food and pharmaceutical industries. These organogels are formed upon selfassembly of surfactant-like small molecules into crystalline fibers, sometimes hundreds of micrometers in length, which eventually lead to gelation of oil. Of particular interest is the ability of organogelator systems to structure and immobilize liquid triacylglycerols at very low concentrations (w2%), which could be exploited for a variety of purposes in food products, from the manufacture of spreads to the solubilization, stabilization and delivery of lipid-soluble nutraceuticals. The purpose of this review is to outline the potential applications of edible oil organogels and to summarize the work that has been carried out to evaluate the functionality of organogelators in food systems.
Food Research International, 2007
The textural and structural properties of organogels made by structuring liquid oil with mixtures of stearic acid (octadecanoic acid) and stearyl alcohol (octadecanol) have been studied. Optical, rheological and X-ray diffraction measurements have been used to investigate the influence of temperature, time and composition on the pseudo-binary system. The aim of these experiments is to relate the observed macroscopic behaviour of the organogels to the microscopic molecular ordering within the crystals that form a network. Oscillating strain measurements have been performed on mixtures with various acid to alcohol ratios. A synergetic effect in structuring was obtained by applying a 3:7 (acid:alcohol) ratio. Hardness and elastic modulus were significantly higher compared to samples with other ratios, at the same overall structurant concentration. Microscopy showed that the crystal habit of the structurant strongly depends on the composition of the mixture. X-ray diffraction experiments, which show that mixed crystals are formed when structurant mixtures are used, confirmed this result. The observed behaviour of the elastic modulus is likely the result of the difference in the microstructure of the interlinked crystals.
Wetting of fat crystals by triglyceride oil and water. 1. The effect of additives
Journal of The American Oil Chemists Society, 1995
Wetting of fat crystals has been extensively examined in this work by contact angle (θ) measurements of fat crystal, oil, and water in three-phase contact. Contact angle was measured in oil. The crystals were nonpolar and wetted by oil for a contact angle equal to 0°, and polar and wetted by water for an angle equal to 180°. Fat crystals are expected to contribute to the stability of margarine emulsions if they are preferentially wetted by the oil phase (0°<θ<90°), but result in instability if they are preferentially wetted by the water phase (90°<θ<180°). In the absence of oil and water additives, fat crystals in α and β' polymorphs were introduced to the oil/water interface from the oil side (contact angle θ ∼ 30°). β Polymorphs were completely wetted by oil (θ ≈ 0°). The contact angle for β' crystals decreased with increasing temperature and was slightly lower in butter oil than in soybean oil. Emulsifiers in the oil phase (lecithins, monoglycerides and their esters, ethoxylated emulsifiers) and surface-active proteins in the water phase (milk proteins) made the crystals more polar (higher θ). Nonsurface-active proteins, sugar, and citric acid had no significant effect, although concentrations of salt lowered θ. Contact angle increased with temperature for emulsifiers of limited solubility in the oil, e.g., saturated monoglyceride.
Quantification of the physical structure of fats in 20 minutes: Implications for formulation
Lipid Technology, 2014
One challenge facing the fat industry involves finding healthy fat-replacers that do not compromise the functionality of the product made with them. For the past three years crystalline nanoplatelets (CNPs) have been reported as the smallest crystal unit in different edible fat systems. This paper summarizes the latest understanding in the area of CNP aggregation and the structures that emerge from their aggregation when using the techniques of ultra small angle X-ray scattering and modelling with computer simulation. An understanding of how these CNPs aggregate should allow the engineering of new healthy fat-replacers.
Fat crystallisation at oil–water interfaces
This review focuses on recent advances in the understanding of lipid crystallisation at or in the vicinity of an interface in emulsified systems and the consequences regarding stability, structure and thermal behaviour. Amphiphilic molecules such as emulsifiers are preferably adsorbed at the interface. Such molecules are known for their ability to interact with triglycerides under certain conditions. In the same manner that inorganic crystals grown on an organic matrix see their nucleation, morphology and structure controlled by the underlying matrix, recent studies report a templating effect linked to the presence of emulsifiers at the oil/water interface. Emulsifiers affect fat crystallisation and fat crystal behaviour in numerous ways, acting as impurities seeding nucleation and, in some cases, retarding or enhancing polymorphic transitions towards more stable forms. This understanding is of crucial importance for the design of stable structures within emulsions, regardless of whether the system is oil or water continuous. In this paper, crystallisation mechanisms are briefly described, as well as recent technical advances that allow the study of crystallisation and crystal forms. Indeed, the study of the interface and of its effect on lipid crystallisation in emulsions has been limited for a long time by the lack of in-situ investigative techniques. This review also highlights reported interfacial effects in food and pharmaceutical emulsion systems. These effects are strongly linked to the presence of emulsifiers at the interface and their effects on crystallisation kinetics, and crystal morphology and stability.
Structure and Stability of Fish Oil Organogels Prepared with Sunflower Wax and Monoglyceride
Journal of Oleo Science, 2015
INTRODUCTION Fish oil FO is a natural source of polyunsaturated fatty acids PUFA and contains significant levels of omega-3 fatty acids, eicosapentaenoic acid EPA and docosahexaenoic acid DHA. Some of the beneficial effects of omega-3 PUFA are prevention of a number of diseases, such as coronary heart diseases, inflammation, hypotriglyceridemia, allergies, hypertension, arthritis, autoimmune disorders, and cancer 1. Monoglycerides MG and their derivatives are mainly used as food emulsifiers. Generally, MG is used for the prevention of starch retrogradation due to interaction between MG-amylose and retardation of staleness in bakery and confectionary industries. Also, monoglycerides are used for control of emulsion and foam stability of dairy and oil based products 2. Sunflower wax SW is a vegetable wax derived during winterization of sunflower oil and consists of long chain saturated C-42 to C-60 esters derived from fatty alcohols and fatty acids 3. SW can be used in emulsions for creating new textures in many industries such as cosmetics, pharmaceutical, and paint. Oils and fats are one of the important components of human diet and ingredients of food industry. Oils and fats are preferred as carriers of fat soluble vitamins A, D, E and K and source of essential fatty acids and energy. On the other hand, hydrogenation, partial hydrogenation, fractionation and interesterfication are common technologies to