Unfortunately, HIU creates streaming and particle fractionation effects due to transient cavitation, and this leads to uncontrolled modification of the oleogelator crystalline network. Recently, high-intensity ultrasound (HIU high-power acoustic waves with a frequency above 20 kHz) have been used to tailor the mechanical and functional properties of saturated fats and oleogels 22, 23, 26. However, applying shear force to oleogels often reduces their ability to retain oil because small crystals with fewer junction zones among them are formed 20, 21.
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This makes these systems more stable 24, 25. In systems containing saturated fat, the application of shear force during crystallization aligns the crystals and decreases the oil migration rate due to a more densely packed crystal network (increased tortuosity of the system). The cooling rate and shear force have been used to try to improve the ability of oleogels to retain oil 15, 19, 20, 21, 22, 23. Much effort has been directed to improving oleogel performance by modifying the formulation and processing 16, 17, 18. Unfortunately, this prevents these materials from becoming the ‘fat of the future’ 2, 11, 13, 14, 15. The direct method is most common because it is simple, needs no specific equipment, requires little energy during oleogel preparation and is industrially scalable 12.Ī disadvantage is that oleogels can release oil during storage due to molecular rearrangements. The network entraps the oil and gels the system 11. The oleogelators rearrange themselves during the cooling step to form a crystalline/polymeric network. Structuring agents are dispersed into the oil, and then a heating and a cooling step are successively applied. monoglycerides, waxes, fatty acids, fatty alcohols, ethyl cellulose, phytosterols, phytosterol esters, etc.) to gel the oil 1. The direct method makes use of self-assembling molecules (e.g. Indirect methods are foam, emulsion and solvent exchange and aerogel templating where proteins or polysaccharides are used to prepare the scaffold in which oil is absorbed/retained 10. Oleogels can be prepared using direct 1 and indirect 10 methods.
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![andonstar microscope 302 new york andonstar microscope 302 new york](https://img.fasttechcdn.com/964/9644073/9644073-3.jpg)
Lowering the intake of saturated fats, for example, by using oleogels rich in polyunsaturated fatty acids can help reduce cardiovascular diseases caused by obesity. The annual healthcare costs related to treating diseases caused by/related to obesity is 60 billion euros in Europe 8 and 210 billion dollars in the USA 9. In 2014, 2.5 billion adults and 41 million children worldwide were overweight or obese these numbers have doubled since 1980 7. However, excessive consumption of saturated fats correlates with obesity that in turn causes cardiovascular diseases, metabolic syndrome and type-2 diabetes 4, 5, 6. These crystalline structures are employed as delivery and protective systems and structuring agents 3. Saturated fats are used in the food, cosmetics, and pharmaceutical industries due to their ability to form solid and crystalline structures at room temperature. Oleogels were developed during the last 15 years as saturated and hydrogenated fat substitutes 2. Oleogels are lipid-based materials that contain 85%–99.5% liquid oil trapped in a network of structuring molecules called oleogelators 1. These results may extend beyond oleogels to potentially be used wherever careful control of the crystallization process and final structure of a system is needed, such as in the cosmetics, pharmaceutical, chemical, and food industries. These new structures act as physical barriers in reducing the migration kinetics of a liposoluble colorant compared to statically crystallized oleogels. The thickness of these bands is proportional to the USSW wavelength. Homogeneous, dense bands of microcrystals form independently of oleogelator type, concentration, and cooling rate.
![andonstar microscope 302 new york andonstar microscope 302 new york](https://i.ytimg.com/vi/TDvTs3QLFTc/maxresdefault.jpg)
During crystallization, the growing crystals move towards the US-SW nodal planes. We employ ultrasonic standing wave (USSW) fields to modify oleogel structure. However, this is unattainable with state-of-the-art technologies. Promising oleogels are unstable during storage, and to improve their stability careful control of the crystalline network is necessary. Oleogels are lipid-based soft materials composed of large fractions of oil (> 85%) developed as saturated and hydrogenated fat substitutes to reduce cardiovascular diseases caused by obesity.