Chemical characterization of four widely appreciated edible mycorrhizal mushrooms: nutrients and bioactive compounds

Mushrooms have been consumed not only as a part of the normal diet, but also as a delicacy due to their highly desirable taste and aroma. Besides, the nutritional, tonic and medicinal properties of mushrooms have been recognized for a longtime. In addition to their nutritional value, some mushrooms may also have a medicinal value; antitumor, antiviral and hypolipidemic effects have been reported . This work reports the chemical characterization of four wild edible mycorrhizal mushrooms: Amanita mairei, Boletus regius, Russula aurea and Russula virescens, appreciated all over the world. The nutritional value was assessed through the composition in macronutrients determined following official procedures; individual procedures; individual profiles in sugars and fatty acids were obtained by HPLC-RI and GC-FID, respectively. Bioactive compounds such as tocopherols were analysed by HPLC- fluorescence. Carotenoids were determined spectrophotometrically. Organic acids and phenolic compounds were determined by UFLC-PDA and HPLC-DAD, respectively. The antioxidant potential was evaluated through the free radical scavenging activity, reducing power and lipid peroxidation inhibition. Carbohydrates were the most abundant macronutrients present in the studied species, and the highest levels were found in B. regius. Mannitol and trehalose were the main sugars quantified in the analyzed samples. Unsaturated fatty acids predominated over saturated fatty acids, being A. mairei and B. regius the species with the highest content in unsaturated fatty acids. The studied species revealed to possess power - ful ant ioxidants such as tocopherols, lycopene, and phenolic compounds (mainly phenolic acids). B. regius was the species with the highest levels of tocopherols, citric acid and phenolic compounds, presenting also the highest antioxidant activity. Overall, the bioactive compounds identified in the studied wi ld mycor r hizal mushrooms could be extracted for the purpose of being used as nutraceuticals. Since these are edible species, they can also be incorporated directly in diet acting as functional foods.