Catering to an aging population in the U.S., Cornell food scientists have devised a nutritious snack made from milk proteins envisioned for people who have trouble swallowing and lactose intolerance. These protein puffs dissolve in your mouth nearly instantly. 

“It’s a snack, it’s a supplemental food, it’s a protein-rich source and it can be a great source of fiber,” said Jessica Uhrin, a doctoral student in food science, and co-author of “Orally Self-Disintegrating Milk Protein Puffs Enriched with Food By-Products for The Elderly,” forthcoming December 2024 in Food Chemistry.

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A low-temperature procedure called supercritical fluid extrusion transforms the skim milk powder into billowy morsels seniors can easily enjoy. 

“There’s a huge population that can benefit from milk protein puffs,” Uhrin said.

 While dysphagia – difficulty swallowing – can happen at any age, according to the paper it correlates mostly with advancing age, occurring in up to 33% of seniors who live independently and up to 51% of seniors living in institutional surroundings, such as assisted living centers.

“If you look at nutritional dysphagia products on the market, they are liquid that you must carry around and keep in the refrigerator,” said Uhrin, who works in the laboratory of Syed Rizvi, professor in the Department of Food Science in the College of Agriculture and Life Sciences, a senior author on the paper. Milk protein puffs designed to self-disintegrate in the mouth are not yet commercially available, she said, but “our product creates a nice new space for elderly supplemental foods.”

To understand how milk puffs are made, consider cheese curls. These are formed through a standard extrusion process where a corn-based slurry is forced through a machine, heated, expanded with steam and then dusted with cheese flavoring. 

In standard extrusion, the lactose (sugar) in milk puffs would caramelize – turning the product dark brown, indicating the degradation of heat-sensitive proteins and bioactive compounds, thus limiting formulations to mostly starch-based ingredients. 

For the milk puffs, the Cornell scientists use lactose hydrolyzed skim milk powder – where the lactose is converted into simpler sugars. A slurry containing the powder is then processed using a low-temperature, low-shear supercritical fluid extrusion process developed in Rizvi’s lab that puffs the protein with high-pressure carbon dioxide. 

By using hydrolyzed skim milk powder, lactose-intolerant seniors can consume the puffs without worrying about digestion issues, the researchers said.

Co-author Aamir Iqbal, a postdoctoral researcher, successfully added apple pomace to give the puffs additional nutrition and a light, fruity taste. This increased dietary fiber and the functional ingredients of flavonoids (antioxidants), anthocyanin (an anti-inflammatory component), polyphenol (a disease inhibitor) and vitamin C. 

The researchers also added acid whey, a byproduct of the dairy industry, which contains valuable micronutrients. With the addition of fruit and dairy by-products, these puffs become nutritionally more desirable, Iqbal said.

“Look at your grocer’s cereal aisle,” Rizvi said. “It’s cereal after cereal after cereal. They are mostly starch based. You won’t see many with milk protein as the primary ingredient. 

“Our puffs are nutritionally attractive,” he said. “There is a lot of criticism of ultra-processed food, and rightfully so, but we have modified and developed a novel technology that allows us to perform the same process – extrusion – but at a lower temperature and shear. This helps us not only maintain the nutritive quality but also produce soluble dietary fiber from the sugars during the process. 

“Food technology serves a purpose,” Rizvi said.

This work was supported by the New York State Dairy Promotion Order, the Foundation for Food and Agriculture Research and the New York Apple Association.