Pro Tip: High hydrostatic pressure has been used for decades to improve food safety and quality, but it can also improve protein functionality.
Beginning in 1980s, the food industry began to experiment with high-pressure processing to improve food safety and quality. These methods are now broadly applied in batch and semi-continuous process where foods and ingredients are subjected to equal pressures in all directions.
At room temperature, pressures between 400 and 700 MPa are commonly used because they can deactivate enzymes associated with food spoilage, destroy cellular membranes and deactivate some foodborne pathogens with less impact on the food than traditional preservation methods.
If pressure alone is insufficient, combining pressure and temperature leads to comparable food spoilage and pathogenic inactivation at lower temperatures, thus preserving food quality. Fairly recently, high-pressure processing has been used to functionalize protein- and starch-based ingredients in ways that may improve their performance in the baking industry.
At pressures above 500 MPa, many enzymes denature, causing a loss of functionality, but the changes in water structure that lead to this protein unfolding are also being applied to enhance the functionality of proteins from diverse sources.
Milk proteins, pulse-based proteins and even gluten have been subjected to high-pressure processing, and these proteins undergo changes in structure that change the types of gels and emulsions they form.
In emulsification, high-pressure processing denatures protein, exposing hydrophobic regions on the protein interior, facilitating stronger interactions between the protein and oil droplets. Protein-based emulsions made at pressures greater than 300 MPa produce smaller than average oil droplet sizes, as well as have more protein stabilizing them.
Pressure also changes the ways in which proteins and starch form gels. In wheat dough supplemented with oat flour, oat flour that underwent pressure treatment led to increases in loaf volume and better crumb structure than untreated flour.
Gluten treated with pressure leads to stiffer doughs, while pressure-treated wheat starch is shown to gel at lower temperatures, forming similarly rigid structures as untreated flour.
There are many applications of high-pressure processing, and it is a clean label method that can lead to novel gel textures and better emulsions, especially from protein-based ingredients.
Harrison Helmick is a PhD candidate at Purdue University. Connect on LinkedIn and see his other baking tips at BakeSci.com.
His research is conducted with the support of Jozef Kokini, Andrea Liceaga, and Arun Bhunia.