It’s not an old saying that oil and water don’t mix completely accurate. While it is true that the two compounds are not naturally combined, they can be converted into a single final product. All you need is an emulsifier, a component that is commonly used in the food industry.
Yangchao Luo, an associate professor at the University of Agriculture, Health and Natural Resources, is using an innovative emulsification process to develop a more stable fat for food manufacturing.
Luo is working on something known as High Phase Internal Pickering Emulsions (HIPE). The high internal phase means that the mixture is at least 75% oil. Pickering emulsions are those that are stabilized by solid particles.
Previous research on pickering emulsions has focused on non-edible particles, but Luo is interested in bringing HIPEs into the food industry as an alternative to trans and saturated fats.
This new approach could have a significant impact on how food is produced and make it easier for food manufacturers to incorporate healthier fats.
Many processed foods are loaded with saturated fats and trans fats to achieve flavor and extend the shelf life of a product. Consuming these fats can increase your risk of cardiovascular disease, type 2 diabetes and LDL cholesterol.
However, not all fats are bad. We need fat in our diet to promote normal cellular function and there are healthy alternatives such as olive, avocado and sunflower oils.
Saturated fats and trans fats are solids at room temperature, which means that a suitable substitute should be a solid. Healthy oils are liquid at room temperature. Luo is facing this challenge by using edible nanoparticles to turn these oils into gels.
Luo has been combining healthy oils, sunflower, soybean or avocado oil with water and nanoparticles to create edible HIPEs. The nanoparticles that Luo uses to create this emulsion come from food sources such as egg yolks, soy protein and milk protein. When the oil is stabilized, it becomes a gel-like block.
“The nice thing is that we have edible food-grade nanoparticles in this system,” says Luo, a member of the Department of Nutrition Sciences. “We are trying to extract and purify these nanoparticles from food and then reuse them in this type of emulsion structure so that they can maximize the nutritional benefit to consumers and also the quality of the food.”
The nanoparticles that Luo works with can be extracted from the food source without the use of inedible chemical solvents. They must also be digestible and have a very uniform structure. The latter is essential to ensure that the oil molecules are completely covered to create room, otherwise it may be too liquid to mimic the texture of saturated fats and trans fats.
Luo emulsions are being tested for both liquidity and solidity. Luo is working to achieve the right balance between oil and stabilizing nanoparticles.
“If you have too much oil in it, the room can be very stiff and hard to chew,” Luo says. “But if it’s too little, it can be quite fluid, so it doesn’t mimic the texture of solid fat.”
In a recent study published in the journal Food Hydrocolloids, Luo determined the optimum cooking temperature and pH for these emulsions.
The ideal cooking temperature, Luo found, is 80 degrees Celsius, which is the temperature of food that is often exposed to pasteurization. The ideal pH is slightly acidic, between 4 and 5.
One of the challenges Luo is struggling with is that unlike saturated fat and trans fat, the oils he is working on are subject to oxidation. Adding natural antioxidants like vitamin E and C to the emulsion helps to counteract this.
One of the most important considerations for making HIPEs an attractive option for the food industry is to ensure that the products used are long-lasting, including that they can be frozen and thawed. In addition, many foods use a lot of sodium, which can destabilize an emulsion.
Overcoming these challenges is the next step in developing HIPEs as a viable alternative to the food industry.
Replacing trans and saturated fats with healthier options in addition to its inherent health benefits, Luo says, researchers can also add nutrients to HIPEs.
Luo is working with teachers at the School of Engineering to print HIPEs in 3D to create an autonomous food packed with essential nutrients. This can be a great benefit for those who have difficulty swallowing, such as young children or the elderly.
This development may also have precision feeding applications, as both water and oil are easily adapted to consolidate soluble and fat-soluble foods in a single food product.
“We hope to achieve this in the near future by 3D printing and combining different nutrients so that this product can be customized for different populations,” says Luo.
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