Cultivo submerso de cogumelo amazônico visando a produção de biomassa micelial para aplicação como alimento funcional

Abstract

Mushrooms are considered a promising source of biomolecules capable of inhibiting the digestive enzymes of carbohydrates and lipids, which can be used for the development of functional foods with a view to the prevention and/or treatment of pathologies such as type 2 Diabetes Mellitus (DM2) and obesity. In this sense, this work aimed to investigate the production of mycelial biomass of a Pleurotus ostreatus isolated from the Amazon, outlining the optimization of the parameters of submerged fermentation, with a view to being used in the elaboration of a functional yogurt, applied to the prevention of DM2 and obesity. The submerged fermentation experiments were carried out in a 2x2 factorial design, varying carbon and nitrogen sources. The mycelial biomass produced was subjected to extraction in hexane, methanol and water and to proximate composition analysis. In the extracts, antioxidant activity

(DPPH, ABTS, chelating ability and reducing power), inhibition of digestive enzymes (α- glucosidase, α-amylase and lipase), total phenolic compounds, flavonoids, soluble proteins and

reducing sugars were quantified. Lyophilized mycelial biomass was subjected to FTIR analysis and in vivo carbohydrate tolerance tests. In the preparation of cupuaçu yogurt, 4 formulations were prepared, corresponding to 0, 3, 5 and 7% of incorporated mycelial biomass. Yogurts were evaluated for physicochemical properties (pH, titratable acidity and °Brix), proximate composition, antioxidant activity (DPPH, ABTS, chelating ability and reducing power), as well as quantification of total phenolic compounds. At 9 days of submerged fermentation, in a medium containing sucrose and soy peptone, there was greater inhibition of digestive enzymes,

where the aqueous extract showed 91.39% and 98.39% inhibition of α-amylase and α- glucosidase, respectively, while the hexane extract exhibited 70.39% inhibition of lipase,

justifying this fermentation time for the production of mycelial biomass rich in bioactive compounds. The methanolic and aqueous extracts exhibited high levels of phenolic compounds, while the hexane extract had a higher content of flavonoids. On the other hand, all extracts showed a low concentration of reducing sugars, as well as differences in protein content, in relation to the methods used, with the highest values obtained by the Lowry method. Additionally, methanolic and aqueous extracts showed high antioxidant capacity, with emphasis on DPPH, ABTS and chelating ability. Regarding the FTIR, spectral vibration of phenolic compounds were observed in the mycelial biomass, corroborating the quantification assays. In in vivo assays, mycelial biomass interfered with starch and sucrose digestion in male Wistar rats, slowing glucose absorption. As for the elaboration of yogurts, the formulations obtained corroborate the Brazilian legislation regarding dairy beverages in relation to pH and titratable acidity. In the proximate composition, yogurts showed high levels of proteins, carbohydrates, fibers and minerals, when compared to studies reported in the scientific literature. In addition, the presence of phenolic compounds was observed, which may be associated with the antioxidant capacity found in these extracts. In view of this, it can be inferred that the mycelial biomass of P. ostreatus isolated from the Amazon presented in vivo and in vitro potential for inhibiting digestive enzymes, suggesting its use in the prevention of diseases such as DM2 and obesity, in addition to the activity associated antioxidant and nutritional potential. Additionally, yogurt made with 5 and 7% of the mushroom shows promise for human consumption, since it has nutritional and therapeutic potential.