Short flashes of ultraviolet light can boost the levels of vitamin D in mushrooms in just seconds, say researchers.
The US research promises to super charge levels of the sunshine vitamin in the fungi using rapid pulses of ultraviolet (UV) light.
Led by Professor Robert Beelman from Penn state University in the USA, the team find that UV light increased the level of vitamin D2 in a single serving of mushrooms from practically zero to more than 100% of the recommended dietary allowance (600 international units) in under a second.
"The scientific community is discovering that vitamin D has many more health benefits than just bone health, which it's primarily known for," said Beelman. "We know, for example, that it helps to regulate hundreds of genes."
"We are hoping that mushrooms that are treated with this technique could be a real benefit for human health by serving as an excellent source of vitamin D and especially as a source for persons who may be at risk of vitamin D deficiency," said Michael Kalaras of Penn State, who worked with Beelman.
The UV treatment did not negatively affect the appearance or taste of the mushrooms, added Beelman.
The sunshine vitamin
The researcher explained that the human body naturally uses the ultraviolet light from the sun to convert cholesterol in the skin to create most of the vitamin D it needs for functions - such as maintaining bone health and regulating the immune system.
However, vitamin D deficiency is a common problem and many consumers also receive vitamin D from food products like enriched milk and orange juice.
The researchers, who were awarded a patent for the method, focused ultraviolet light that can flash high energy light waves several times a second onto the surface of the mushrooms.
Pulsed light was able to rapidly convert ergosterol in the mushrooms to vitamin D2 in less than a minute.
This process of converting ergosterol to vitamin D2 is similar to how humans and animals can synthesize Vitamin D3 from cholesterol in the skin, explained the researchers.
Beelman said the pulsed ultraviolet light method is more efficient than other methods to boost vitamin D in mushrooms because it only takes a few seconds of the treatment to significantly increase the levels.
In a previous method, another group of researchers used a constant stream of ultraviolet light over several hours to increase the vitamin D levels of mushrooms. However, this constant exposure to ultraviolet lighting darkened the appearance of the mushrooms, Beelman said.
However the new method using pulsed light did not turn white mushrooms brown or cause other discolorations, which some consumers find undesirable, explained Kalaras - who noted that both sliced and whole mushrooms were tested, with vitamin D levels in sliced mushrooms reaching higher levels than whole mushrooms.
Vtamin D remained in the mushrooms even after a week in storage, the team said.