The old adage that oil and water do not mix is not completely accurate. Although it is true that the two compounds do not combine naturally, their transformation into one end product can be done. All you need is an emulsifier, an ingredient often used in the food industry.
Yangchao Luo, an associate professor at the College of Agriculture, Health and Natural Resources, is using an innovative emulsification process to develop healthier, storage-resistant fats for food production.
Luo works with something known as High Internal Phase Pickering Emulsions (HIPE). High internal phase means that the mixture is at least 75% oil. Pickering emulsions are those that are stabilized by solid particles.
Previous research into Pickering emulsions has focused on inedible particles, but Luo is interested in introducing HIPEs to the food industry as an alternative to trance and saturated fats.
This new approach could have a major impact on the way food is produced and could make it easier for food producers to include healthier fats.
Many processed foods are loaded with saturated and trans fats to taste and to extend the shelf life of the product. Consumption of these fats may increase the risk of cardiovascular disease, type 2 diabetes and LDL cholesterol.
However, not all fats are bad. We need fat in our diet to maintain normal cellular function, and there are healthy alternatives such as olive oil, avocado and sunflower oil.
Saturated fats and trans fats are solid at room temperature, which means that the appropriate substitute must also be solid. Healthy oils are liquid at room temperature. Luo tackles this challenge by using edible nanoparticles to transform these oils into gels.
Luo is working on combining healthy oils, such as sunflower, soy or avocado oil with water and nanoparticles, to create edible HIPE. The nanoparticles that Luo uses to create this emulsion come from food sources such as egg yolks, soy protein and milk protein. Once the oil stabilizes, it turns into a gel-like block.
“The cool thing is that we have edible nanoparticles in this system,” said Luo, who is a member of the Department of Food Science. “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 provide maximum nutritional benefits as well as food quality for consumers.
The nanoparticles that Luo works with must 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 crucial to ensure that they will completely cover the oil molecules so that the gel can form, otherwise it may be too liquid to mimic the texture of saturated and trans fats.
Luo tests the emulsions for fluidity or how liquid versus solid they are. Luo is currently working on striking the right balance between oil and stabilizing nanoparticles.
“If you have too much oil there, the gel can be very hard and difficult to chew,” says Luo. “But if there’s too little, it can be quite runny so it doesn’t mimic a hard, greasy texture.”
In a recent study published in Food Hydrocolloids, Luo determined the optimal cooking temperature and pH for these emulsions.
Luo found that the ideal cooking temperature is 80 degrees Celsius, which is the temperature at which foods are often exposed during pasteurization. The ideal pH is slightly acidic, between 4 and 5.
One of the challenges Luo struggles with is that, unlike saturated and trans fats, the oils he works with are subject to oxidation. Adding natural antioxidants such as vitamins E and C to the emulsion helps counteract this.
One of the most important considerations for making HIPE an attractive option for the food industry is to ensure that the products in which they are used have a long shelf life, including the possibility of freezing and thawing. In addition, many foods use a lot of sodium, which can destabilize the emulsion.
Overcoming these challenges is the next step in the development of HIPE as a viable alternative for the food industry.
In addition to the inherent health benefits of replacing trance and saturated fats with healthier options, Luo says researchers may also add nutrients to HIPE.
Luo is working with professors at the HIPE School of 3D Printing Engineering to create a stand-alone food product full of essential nutrients. This can be a great benefit for those who have difficulty swallowing, such as young children or the elderly.
This development can also have applications for precision nutrition, as the water and oil content are easily adjustable to enrich water-soluble and fat-soluble nutrients in a food product.
“We hope that in the near future we can really do this by 3D printing and combining different nutrients so that we can customize this product for different populations,” says Luo.
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