Superheated steam lets you fry without fat

Superheated steam (SHS) could become the frying and drying technology of choice as manufacturers learn more about its unique benefits, according to Dutch contract research organisation TNO.

TNO - which has a division specialising in novel processing techniques, including pulsed light and high pressure processing - said SHS was generating a lot of interest in the food industry.

Dr Ronald Visschers, programme manager, food and biotechnology applications, said: “Although it’s steam, it doesn’t make things wet, so you can use it for everything from drying ingredients, fruits and vegetables to blanching, sterilisation, pasteurisation and toasting. However, the most exciting applications are frying - without oil.

“We have done several studies on frying in SHS. Confidentialityplays a role in the examples we can share; however, beyond fries, we have conducted studies on expanded pellet snacks, meat, fish, meat and fish snacks, and bakery.

"It works by circulating superheated steam at 200°C within a closed environment, effectively enabling companies to fry without fat. SHS replaces the second frying step for fries and other snacks, reducing fat and calories without losing crispiness, colour, aroma or flavour.”

Typically, chips were fried with 5% fat and then fried again at catering outlets, adding another 6-7% fat, he said. “By using SHS, you could remove the second step and halve the fat content. It’s also a very mild procedure, so helps products retain more nutrients by reducing the risk of oxidation. If you’re using it to dry vegetables or fruits for putting in packets of cereal for example, it reduces the decomposition of easily oxidised nutrients such as Vitamin C.”

In terms of drying applications, SHS was also far quicker than hot air drying, and far cheaper than freeze drying, he added.