Saturated and trans fats are commonly used in the food industry to both flavor food and extend its shelf life, however, consuming these fats can increase the risk of health issues such as cardiovascular disease, type 2 diabetes and high LDL cholesterol levels. Healthier fats from sources like olives, avocados, sunflowers and soybeans are oils at room temperature, making them difficult to simply substitute into food products as a replacement for less healthy fats. Researchers at the University of Connecticut’s College of Agriculture, Health and Natural Resources are seeking to overcome this challenge and make it easier for the food industry to adopt healthier fat choices by developing nanoparticle technology that transforms healthy oils into edible substances that share the favorable properties of saturated and trans fats without the health risks.
The researchers’ technology centers around high internal phase Pickering emulsions (HIPEs). Pickering emulsions are those that are stabilized by solid particles, while high internal phase refers to a mixture that is at least 75% oil. While previous research in Pickering emulsions has focused on non-edible particles, the team hopes to use the technology to transform healthy liquid food oils into gel-like substances that better mimic the texture of solid fat sources. In order to be used in the food industry, the nanoparticles used in the emulsions must be extractable from a food source without the use of inedible chemical solvents, must be digestible and have a very uniform structure in order to ensure the formation of a gel. The nanoparticles currently being developed are extracted and purified from food sources like egg yolks, soy protein and milk protein.
To develop a viable fat substitute, the team is working to strike the right balance between oil and stabilizing nanoparticles, testing the emulsions for factors such as flowability. Recently, the researchers determined the optimal cooking temperature and pH for the edible HIPEs. The ideal cooking temperature was found to be about 80 degrees Celsius, which is a temperature food products are often exposed to during pasteurization. The ideal pH is slightly acidic, between 4 and 5. These results were recently published in the journal Food Hydrocolloids.
One challenge the team is now working to overcome is the fact that, unlike saturated and trans fats, the oils they are working on are subject to oxidation. So far, adding natural antioxidants like vitamin E and C to the emulsion has helped to counteract this issue. One of the next steps is to ensure that food products incorporating HIPEs will have a long shelf life, including being able to be frozen and thawed. The researchers are also tackling the challenge of high sodium content in many food products, which could destabilize the emulsion.
In addition to the inherent health benefits of replacing trans and saturated fats with healthier options, the researchers say additional essential nutrients could be added to the HIPEs. Because both the water and oil contents of the HIPEs can be easily tuned to fortify water-soluble and fat-soluble nutrients in a single food product, the technology could have applications for precision nutrition. The team is now working with faculty in the UConn School of Engineering to 3D print HIPEs in order to create a stand-alone food product packed with essential nutrients.
“We’re hoping in the near future we can really make this by 3D printing and putting different nutrients together so we can personalize this product for different populations,” said co-author Yangchao Luo, an associate professor and member of UConn’s Department of Nutritional Sciences.
Photo: Yangchao Luo, associate professor in UConn's College of Agriculture, Health and Natural Resources. Credit: Jason Shelton, UConn Photo