Mushrooms should be microwaved to seal in goodness, scientists say!

By Matthew Healy

Mushrooms should be grilled or microwaved to maintain their nutritional value, according to new research.

The study suggests that cooking mushrooms that way enables them to maintain high levels of essential amino acids and vitamins to keep blood cells healthy, produce energy and help metabolise fats and proteins.

Microwaving increases the content of anti-inflammatory and antioxidants like polyphenol while other techniques like boiling or deep frying sees antioxidant levels plummet due to "leeching" from the liquid they are cooked in.

Scientists at the Mushroom Technological Research Centre at La Rioja, Spain, tested four types of raw and cooked fungi to measure their antioxidant activity.

Lead scientist on the project; Irene Roncero said: "Frying and boiling produced a more severe loss in proteins and antioxidants compounds, probably due to the leaching of soluble substances in the water or in the oil, which may significantly influence the nutritional value of the final product.

"This minimal amount will not cause nutrient loses by leaching; in fact, the antioxidant capacity can be even improved. Moreover, if olive oil is used, the fatty acid profile of the final preparation is enhanced with barely increase in the calorie content."

Mushrooms contain a high protein content and provide vitamins B1, B2, B12, C, D and E as well as minerals such as zinc and selenium.

They are also an important source of biologically active compounds with potential medicinal value such as betaglucans, which reduces the risk of heart disease.

Ms Roncero and her team tested white button mushroom, shiitake, oyster and king oyster mushrooms harvested from onsite facilities in La Rioja, Spain.

After the cooking process, raw and cooked mushrooms were freeze dried before the antioxidants inside were analysed. Frying mushrooms sees severe losses in protein, ash, and carbohydrates content but increased the fat and energy.

Boiling improves the total glucans content by enhancing the betaglucans fraction but antioxidant levels are decreased significantly in both methods.

Ms Roncero said: "When mushrooms were cooked by microwave or grill, the content of polyphenol and antioxidant activity increased significantly, and there are no significant losses in nutritional value of the cooked mushrooms."

"The adequate selection of the culinary method is a key factor to preserve the nutritional profile of this highly consumed food."

The findings were published in the International Journal of Food Sciences.