HPP has been used in food production since the late 1990s in the US to inactivate pathogens, yeasts and molds; boost shelf-life; and maintain colors, textures, flavors and nutrients that can be damaged by heat treatment, Dr Errol Raghubeer, senior food scientist at HPP expert Avure, told FoodNavigator-USA.
It has also enabled firms to create innovative new products such as fresh purees for yogurts with extended shelf-life or high-quality prepared seafood products (HPP frees meat from shells without damaging it), he said.
Reduce or eliminate sodium-containing preservatives
However, many manufacturers are only just beginning to understand the role HPP can play in sodium reduction, he said.
“By using HPP you can significantly reduce or even eliminate the use of sodium-containing preservatives such as sodium lactate, sodium diacetate and sodium nitrite in deli meats, or sodium benzoate in wet potato salads, hummus and macaroni salads.
“In the case of hummus, you can actually significantly improve the flavor, clean up the label and reduce sodium by using HPP instead of sodium benzoate.”
Textural and nutritional benefits - as well as cleaner labels…
There are also textural benefits to using HPP, he said.
“Again, hummus is a great example. If you apply pressure to hummus it makes it taste and feel better in the mouth.”
In other applications, firms had found they could avoid using certain gums and starches owing to textural benefits from using HPP, he said.
“There are also fat reduction opportunities. For example, by using HPP you can create a dressing with half the calories that uses yogurt as a base rather than regular mayo and you don’t get syneresis problems [where the fat separates from the water].
"We've seen several companies in ready-to-eat deli foods optimize the organoleptical properties of their products because of the positive effects of HPP on hydrocolloids and proteins. The results are improved viscosity, mouthfeel and the reduction of syneresis."
How HPP works
HPP - or ‘cold pasteurization’ - allows products to be treated in their final packaging, with flexible containers carrying the product into a high-pressure chamber, which is flooded with cold water and pressurized for a few minutes.
The pressure acts uniformly and instantly, regardless of the products’ size or shape, causing lethal damage to the cellular structure of bacteria, molds and yeasts.
The high hydrostatic pressure does not damage the structural components of the food itself (proteins, fibers, fats, etc.), nor does it affect the structural integrity of the package used, he said.
“One thing companies need to think about is that if you are going to have a product that has 120 days’ shelf life instead of 60 days, you may need to make sure that your packaging film is still suitable. Is oxygen going to get into your product?”
While the capex costs can be high for smaller manufacturers to buy their own HPP equipment, there was a growing trend to a toll manufacturing system whereby several companies will feed product into a central HPP facility, he said.