Frying food bad for your diet and lungs
Having a fry up really is not only bad for your diet but also bad for your lungs because you breathe in tiny droplets of hot fat, a study found.
As food is fried, water droplets “explode” not only spitting hot fat onto your skin but into the air forming dangerous indoor pollution.
And chicken, other meat pumped with water or Chinese stir frys are the worst offenders.
Scientists at Texas Tech University and Utah State University heated up oil in a frying pan and then recorded what happened when droplets of water were added.
Assistant professor Jeremy Marston at Texas Tech University, said: “Regardless of culinary skills, most people who have used a stove top have encountered the result of water interacting with hot oil.
“The phenomenon is particularly memorable if the result is impingement of hot fluid on one’s skin.
“Whilst ubiquitous, a deeper probing of this phenomenon reveals a vastly rich dynamical process.
“We’ve discovered that a very large number of small oil droplets are released when even a single, small droplet of water comes into contact with hot oil.
“The resulting phenomena is dramatic – you can see the explosive release when the water, trapped under the oil, vaporises all of a sudden.
“This causes the oil film to rupture and sends oil droplets flying.”
Explosive oil droplets
A surprising find was the released oil droplets can be submicron sized, making them potentially hazardous because they can be inhaled.
The scientists are currently assessing the true size distribution of oil droplets released and how far into the ambient environment they can reach with or without proper ventilation.
Prof Marston said: “It’s known that millions of deaths worldwide occur due to indoor air pollution, but we don’t know yet how much cooking in poorly ventilated kitchens contributes to it.
“And since some of the droplets are inhalable and potentially hazardous, we’re also planning to use an ‘aerosol particle sizer’ that can measure down to the nanometer sizes to see just how small these particles can be.”
He noted chicken breasts contain a high volume of water and the higher the water content, the more explosive droplets are created.
Prof Marston added: “Our research may be particularly relevant to Chinese cooking methods in which water is added to hot woks.”
The scientists will next focus on more detailed imaging with high-speed video .
He said: “To explore the fundamental science, we’ll perform three-dimensional volumetric imaging and thermal imaging to assess the dispersion of the aerosols released in cooking,
“We’ll also perform some preliminary trials using a new air curtain that could be integrated into current ventilation systems.
“We’re planning to conduct a detailed study to quantify how much impact kitchen-based aerosols have on indoor air pollution.
“Ultimately, we hope that our research can guide designs for improved ventilation systems to remove these ultrafine aerosols.”
The findings were presented during the 70th annual meeting of the American Physical Society’s Division of Fluid Dynamics in Denver, Colorado.