Grilling or Microwaving Best Ways to Preserve Nutritional Value of Mushrooms

22 May 2017 --- A study by Spanish researchers has shown that microwaving and grilling are the best ways to prepare mushrooms in terms of maintaining their nutritional profile. Mushrooms are considered valuable health foods, since they have a significant amount of dietary fiber and are poor in calories and fat. Moreover, they have a good protein content (20-30% of dry matter) which includes most of the essential amino acids.

Mushrooms also provide a nutritionally significant content of vitamins (B1, B2, B12, C, D and E) and trace minerals such as zinc and selenium. On top of that, mushrooms are an important source of biologically active compounds with a potential medicinal value, such as betaglucans.

Scientists from Mushroom Technological Research Center of La Rioja (CTICH) aimed to evaluate the influence of different cooking methods (boiling, microwaving, grilling and frying) on proximate composition, betaglucans content and antioxidant activity of four of the most widely consumed cultivated mushrooms species: Agaricus bisporus (white button mushroom), Lentinula edodes (shiitake), Pleurotus ostreatus (oyster mushroom) and Pleurotus eryngii (king oyster mushroom). 

The results of this study, published in the International Journal of Food Sciences and Nutrition, revealed that frying induced more severe losses in protein, ash and carbohydrates content but increased the fat and energy. Boiling improved the total glucans content by enhancing the betaglucans fraction. A significant decrease was detected in the antioxidant activity especially after boiling and frying, while grilled and microwaved mushrooms reached higher values of antioxidant activity.

“Frying and boiling treatments produced more severe losses 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,” says Irene Roncero, one of the authors of the paper.

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

The researcher clarifies that adding a little oil portion while grilling mushrooms is not a problem. “This minimal amount will not cause nutrient losses 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 increasing the calorie content.”

Roncero says that the cooking technique clearly influences the nutritional value and the antioxidant activity of mushrooms so that “the adequate selection of the culinary method is a key factor to preserve the nutritional profile of this highly consumed food.”

In this study, the CTICH collaborated with the Estacion Experimental del Zaidin (CSIC, Granada) to analyze the antioxidant activity of the raw and cooked mushrooms.

In an interview with NutritionInsight’s sister publication, FoodIngredientsFirst, Scelta Mushrooms New Business Developer Jan Klerken Jr. recently spoke about the use of mushrooms to reduce the sodium content in products without losing flavor.

According to Klerken Jr. umami flavor compounds, which are naturally present in mushrooms have the ability to improve the palatability and increase perceived saltiness in food products. It makes Scelta Mushrooms’ line of umami-rich extracts a powerful, natural alternative to MSG/I+G/AYE, but also a sodium reduction tool. Sodium reductions of up to 50% have been achieved, without compromising taste and function and without the use of potassium.

“Our umami extracts are a rich source of glutamate, which is obviously very well known within the industry as the perfect taste enhancer,” Klerken Jr. explains. “Glutamate occurs naturally in mushrooms, so we try to capture all these elements together with the rest of the matrix, and find a solution to add to that umami flavor, which can decrease the sodium impact, but which overall gives a higher taste accessibility to the end consumer and that is exactly what we are targeting.”