Snackfood development: protein puffs that are easy to swallow

Cornell University food scientists have developed a nutritious snack made from milk proteins that could be suitable for people who have trouble with swallowing and lactose intolerance. These so-called protein puffs are designed to dissolve in the 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 fibre,” said Jessica Uhrin, a doctoral student in food science, and co-author of the research paper that was published in Food Chemistry.

A low-temperature processing technique — called supercritical fluid extrusion (SCFX) — was used to develop the milk protein-based puffs, enriched with fruit and dairy by-products, designed specifically for seniors having swallowing issues and lactose intolerance.

“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 centres.

“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, and a senior author on the paper.

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

For these puffs, the Cornell scientists used lactose hydrolysed 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.

Co-author Aamir Iqbal, a postdoctoral researcher, added apple pomace to give the puffs additional nutrition and a fruity taste. This increased dietary fibre 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 by-product of the dairy industry, which contains valuable micronutrients.

Using this lower temperature SCFX extrusion method not only helps to maintain the nutritive quality but also produces soluble dietary fibre from the sugars during the process.

The milk protein puffs designed to self-disintegrate in the mouth are not yet commercially available. However, the research paper said the ‘SCFX puffs’ contained higher levels of protein, fibre, phenolics and other nutrients in comparison to other starch-based alternatives.

Image credit: Cornell food scientist