Avaliação do impacto do tipo de substrato e métodos de extração nas propriedade biológicas de extratos de cogumelos

: Pleurotus Citrinopileatus Var. Cornucopiae e Pleurotus Salmoneo Stramineus

Abstract

The use and consumption of mushrooms have been increasing due to the fact that they contain bioactive compounds with biological properties (antioxidant activity, antimicrobial, antidiabetic, antihypertensive, prebiotic, among others). In this context, the aim of this study was to evaluate the impact of substrate type and extraction methods in antioxidant properties, anti-diabetic, anti-hypertensive and prebiotic extracts of two species of mushrooms, Pleurotus citrinopileatus var. cornucopiae and Pleurotus salmoneo stramineus. Both species were produced using two different production methods: growing in standard substrate (I) and the alternative cultivation substrate (II) composed of standard substrate mixture with coffee grounds, 1: 1. The resulting mushrooms were collected, dried and subjected to three different extraction methods , particularly aqueous, enzymaticassisted and ethanolic, to evaluate the impact of the extraction method on the biological properties of mushroom extracts. In the production of P. salmoneo stramineus mushrooms there was a decrease of 86 % in the production yield from substrate II and a morphologically atypical production. Its composition (protein, fat, sugars and organic matter contents) did not vary according to the type of production. Moreover the production yield, morphology and composition did not change for the Pleurotus citrinopileatus var. cornucopiae. When preparing the extracts, the yield was higher in aqueous (60 - 67 %) and enzyme-assisted (58 - 63 %) extractions. In the ethanol extraction a lower yield (25 - 32 %) was reported, however it was this extract that had the highest total sugars content (191 - 299 mg / mg extract). The extracts of the two species of mushrooms did not show antidiabetic activity (30 %) compared to the positive control (89 %), however an aqueous extract of P. citrinopileatus var. cornucopiae I had a good anti-hypertensive activity (IC50 = 123,3 mg/mL). This activity was not detected in ethanol extracts of P. salmoneo stramineus. The water and ethanol extracts of the two mushroom species under study showed prebiotic activity similar to that of commercial positive control fructooligosaccharides (FOS), and there was no difference between production methods (I and II). Antioxidant activity was detected in all extracts, and it was higher in P. citrinopileatus var. cornucopiae I extracts (2.37 to 11.86 mg equivalent acid per gram of lyophilized extract).

Date of Award	19 Feb 2016
Original language	Portuguese
Awarding Institution	Universidade Católica Portuguesa
Supervisor	Sandra Margarida Azevedo Pinto Ferrador (Supervisor)