CAFEÍNA EM COGUMELO Pleurotus ostreatus CULTIVADO COM RESÍDUOS DE CAFÉ

Abstract

Mushrooms are fungi which are used for various purposes, such as in cuisine, medicine, as hallucinogens, ornamental purposes, although there are also those which are poisonous. There has been an increasing interest in producing and consuming edible mushrooms, particularly those belonging to the genus Pleurotus, due to its easy availability. Fermentation of Pleurotus can be done on diverse substrates such as waste pulp of coffee, sugarcane and wheat brans, among others. The chemical composition of mushrooms is affected by the substrate because compounds originally found in substrates may be absorbed or modified by the mushrooms enzymes. The study focused on the Pleurotus ostreatus, whose popular name in Japan is hiratake, and it is the fourth most consumed edible mushroom in the world, commonly called vegetarian meat because its high protein content. This study aimed to determine the caffeine content in edible Pleurotus mushrooms that were inoculated with seeds developed on caffeic substrates and inoculated into hay and in mushrooms produced directly on the coffee seed, without using hay. Additionally, we pursued to identify organic compounds in methanolic extracts of mushrooms using GC-MS. Caffeine extraction from mushrooms was optimized by factorial design 2² followed by validation of and HPLC-UV method for caffeine determination. It was found that the fungus inoculated directly into the coffee seed, without the use of hay, absorbed caffeine through its mycelium and caffeine concentrations in lyophilized mushrooms ranged between 589.6 to 975.0 g/g. For mushrooms grown on coffee residues and inoculated into hay, caffeine was below the limit of quantification. Regarding the amounts of flavonoids, all samples showed relatively low levels. However, mushrooms grown in coffee seeds contained significant amounts of phenolic compounds and, in particular, the mushroom grown directly on the coffee seeds showed greater antiradical activity than the others. Finally, fatty acids, terpenes and sterols were identified by GC-MS in the mushroom samples. The presence of caffeine was confirmed only in mushrooms that had been grown in caffeic substrates, demonstrating that mushrooms can absorb caffeine from subtrates.