Boosting Soy Protein Power for Healthier Homemade Salad Dressing Emulsions

David Palenski
20th January, 2024

Boosting Soy Protein Power for Healthier Homemade Salad Dressing Emulsions

Soybean (Glycine max), the plant where Soy Protein Isolate (SPI) is derived from.

Photo adapted from: Wen-Ling Shen / CC BY (Source)
Consumers are increasingly seeking healthier food options, particularly when it comes to meat products[2]. Traditional meat processing often results in high levels of saturated fats, which are linked to health concerns. One approach to address this is to reduce the fat content or replace animal fats with plant-based oils. However, directly adding plant oils to meat can create issues with texture and stability. Emulsions – mixtures of oil and water that don’t naturally combine – offer a solution, allowing plant oils to be incorporated more effectively[2]. Researchers at Northeast Agricultural University and the University of Veterinary and Animal Sciences, Lahore, have been investigating a specific type of emulsion called a Pickering emulsion to improve the health profile and stability of food products[1]. Pickering emulsions are unique because they use solid particles, rather than typical additives, to stabilize the mixture of oil and water. This study focused on using soy protein isolate (SPI) nanoparticles – extremely small particles derived from soybeans – to stabilize emulsions containing flaxseed-derived diglyceride (DAG), a type of fat. Soy protein is a byproduct of soybean oil production and is already known for its nutritional benefits and ability to stabilize mixtures[3]. The goal was to create a stable emulsion with a desirable texture and improved resistance to separation over time. The process began with modifying the SPI using heat and ultrasound. Ultrasound, which uses sound waves, was applied at different power levels to create nanoparticles of varying sizes. The researchers found that applying 600 Watts of ultrasound power resulted in the smallest SPI nanoparticles (133.36 nanometers) and a specific electrical charge (-34.77 mV, known as zeta potential). While the ultrasound didn’t change the fundamental building blocks of the protein, it did alter its structure. These modified SPI nanoparticles were then used to create the Pickering emulsions with the flaxseed oil. The resulting emulsions were then tested for several key properties. Emulsions created with SPI nanoparticles treated with 450 Watts of ultrasound power showed the best results. They had smaller droplet sizes, a lower zeta potential, and improved emulsifying ability – meaning they were better at keeping the oil and water mixed. Crucially, these emulsions also exhibited a higher “solid-liquid balance,” indicating greater stability, and lower values in tests measuring particle movement and overall stability (mean square displacement, backscattering fluctuations, and turbiscan stability index). Microscopic examination revealed a more compact structure with smaller oil droplets. This research builds upon previous work exploring the use of SPI to stabilize emulsions[3][4]. Earlier studies demonstrated that heating and techniques like sonication or high-pressure homogenization can alter SPI, creating particles capable of stabilizing oil-in-water emulsions. The current study refines this process by specifically utilizing ultrasound at optimized power levels to create even smaller and more effective SPI nanoparticles. Furthermore, the use of flaxseed-derived DAG as the oil phase is significant, as DAG is known to have potential health benefits related to fat metabolism[2]. The findings suggest that combining heat and 450 Watts of ultrasound treatment to SPI creates nanoparticles that are particularly effective at stabilizing DAG-based Pickering emulsions. This results in a product with enhanced microstructure and improved stability, potentially offering a healthier and more appealing alternative to traditional meat products or other foods requiring stable oil-water mixtures.

NutritionBiotechPlant Science

References

Main Study

1) Ultrasonic enhancement of structural and emulsifying properties of heat-treated soy protein isolate nanoparticles to fabricate flaxseed-derived diglyceride-based pickering emulsions.

Published 20th January, 2024

https://doi.org/10.1016/j.foodchem.2024.138469

Related Studies

2) Future trends of processed meat products concerning perceived healthiness: A review.

https://doi.org/10.1111/1541-4337.12813

3) SPI microgels applied to Pickering stabilization of O/W emulsions by ultrasound and high-pressure homogenization: rheology and spray drying.

https://doi.org/10.1016/j.foodres.2019.04.020

4) Influence of varying oil phase volume fractions on the characteristics of flaxseed-derived diglyceride-based Pickering emulsions stabilized by modified soy protein isolate.

https://doi.org/10.1016/j.foodres.2023.113812


Related Articles

An unhandled error has occurred. Reload 🗙