CARACTERÍSTICAS QUÍMICAS DAS FERMENTAÇÕES SUBMERSAS E DO ESTADO SÓLIDO PRODUZIDAS PELO Agaricus brasiliensis EM DIFERENTES SUBSTRATOS

Abstract

Several pharmacological activities are attributed to Agaricus brasiliensis, mainly antitumor activity and immunostimulating, besides being a source of antioxidants. In this study A. brasiliensis was grown on six substrates by submerged and solid-state fermentation. The goal was to determine which is the best host and/or fermentation technique for the growth of microorganisms and getting fermented substrates rich in natural antioxidants. The fermented substrates were separately extracted with hexane and methanol. In the nonpolar extract, ergosterol content was quantified by HPLC and the total steroids content by UV-Vis. The results suggested that there is a significant positive linear correlation between the levels of total sterols determined by UV-Vis and ergosterol values obtained by HPLC for fermentation of A. brasiliensis by cultivation of SF and SSF. The quantitative relationship between these variables showed that the UV-Vis methodology could be used to predict the levels of ergosterol fermented. The nonpolar extraction was optimized by 23 factorial design. The results indicate significant effect of heat source, addition of acid/base, use of drying agent and the interaction of these latter variables, giving smaller amounts of ergosterol. The methodology applied at the ergosterol determination by HPLC and UV-Vis using external standard was validated through the parameters of selectivity, precision, accuracy, linearity, sensitivity and robustness. There was no effect of the matrix on quantification by HPLC. All substrates were shown as good hosts for A. brasiliensis. The sterols present in nonpolar extract were identified by GC-MS. To obtain the polar extract a 23 factorial design was also employed and it was analyzed the effects of solvent, temperature and extraction time on the extraction yield and antirradicalar activity of extracts were also analyzed. Solvent and extraction time were the main significant effects observed in the optimization procedure. The results showed good antirradicalar activity. The total phenolics and flavonoids contents were shown to be superior to the samples fermented compared to levels of vegetable substrates, indicating that A. brasiliensis produces fermented substrates rich in nutraceutical substances. The polar extracts were analyzed by UPLCMS/MS and some ions have been suggested as markers of A. brasiliensis.