New research shows UV-C light treatment increases Vitamin D2 in mushroom caps and stems in both white and brown mushrooms.
Why it matters: These new findings provide farmers with the opportunity to better manage their post-harvest handling and storage and can add value and nutritional benefits to consumers.
Mushrooms are the only produce containing Vitamin D, and much like humans, can create more Vitamin D when exposed to UV light whether from the sun or a sunlamp.
Normally mushrooms contain the pre-vitamin D compound. The mushroom is consumed and then when the body is exposed to UV light, the body creates Vitamin D from that compound.
When exposed to UV light the mushroom can create Vitamin D due to ergosterol, allowing the conversion to happen before the mushrooms are consumed.
"The mushrooms have a significant amount of ergosterol, a compound that is a precursor to Vitamin D. With UV light the ergosterol will go through photolysis and become vitamin D. It is a chemical reaction," says Dr. Suqin Shao, research scientist with Agriculture and Agri-Food Canada (AAFC).
"If we don't shine a lot of light to the mushroom, they would still be pre-vitamin D. The benefit of the UV shining on the mushroom is that they produce it in the mushroom, that Vitamin D, so that saves the converting part in our body," says Dr. Rong Cao, research scientist with AAFC.
The mushrooms did not require long exposure to the UV light for the conversion to happen.
"The maximum time we used is 200 seconds. It's less than four minutes. With such a short treatment we found that the vitamin D in the mushrooms increased about 60 micrograms of Vitamin D in 100 grams of fresh mushrooms," says Shao.
By comparison, the recommended intake of Vitamin D is only 10 to 30 micrograms per day.
Cao says there are two benefits to these findings. The first is the value-added use of byproducts.
"Stems are cut and not used as food. But then we found the stems have significant amounts of antioxidant activities and Vitamin D," says Cao.
Second, the increased vitamin D mushrooms can be sold at a higher premium.
Unfortunately, there is not enough research to show how farmers could incorporate this practice into their operations, but Cao says it would be a niche market product.
"If the government supports that kind of research in the industry and invests in this, there is potential. If a lot of people consume and see these benefits, they will buy more. They don't have that kind of product in the market so they can't buy more," says Cao.
Vitamin D provides many benefits for the human body as it recently has been shown to boost the immune system and also help the body absorb calcium.
"If farmers can produce a mushroom product significantly higher in vitamin D, then that's the value itself, because it's a value-added product. You can sell it as a functional food," says Cao.
"My work is basically focused on providing knowledge of nutrition, and health benefits of mushrooms. We want to try a method to improve the health benefits. I hope that my data from my research will contribute to people's choice when they choose their food," says Shao.