Propriedades nutricional e antioxidante de cogumelos comestíveis Pleurotus ostreatus cultivados em substratos obtidos de resíduos agrícolas.

Abstract

Mushrooms of the Pleurotus ostreatus species are one of the most consumed mushrooms worldwide, as they have low lipid and energy content, but are rich in proteins, carbohydrates, vitamins, dietary fiber and minerals. In addition, they are endowed with secondary metabolites that offer health-promoting action, such as antioxidants, and can degrade lignocellulosic substrates present in agricultural waste. However, the substrate can interfere with the functional attributes of the mushrooms. In this perspective, the objective was to evaluate the influence of agricultural waste banana leaves and sugarcane bagasse on the nutritional and antioxidant potential of P. ostreatus. The study used banana leaves and sugarcane bagasse combined in 5 different formulations as substrate for the mushroom. The mushrooms were cultivated for 120 days and after drying, their physical-chemical composition (moisture, water activity and ash) and nutritional composition (proteins, carbohydrates, lipids and energy) were analyzed. After producing extracts with hydroalcoholic solution, the chemical composition (phenolic compounds and flavonoids) and antioxidant activity were estimated. The experiments were analyzed by one-way ANOVA with Tukey's post-test to determine significant differences (p < 0.05) between treatments. The analysis showed that the samples presented, in their physical-chemical composition, a moisture content ranging from 12.12% ± 0.05 to 13.80% ± 0.14, water activity between 0.54% ± 0 and 0.64% ± 0, and ash content between 3.72% ± 0.05 and 5.00% ± 0.18. In the nutritional composition, the protein content ranged from 14.87% ± 0.02 to 26.25% ± 4.57, carbohydrates between 55.34% ± 4.92 and 66.75% ± 0.08, lipids from 1% ± 0.05 to 1.29% ± 0.12, and the energy value between 325.45 kcal/100g ± 16.89 and 337.94 kcal/100g ± 0.33 kcal/100g. In the chemical characterization, the total phenolic compounds ranged from 805.61 ± 3.95 to 872.33 ± 101.36 µg EAG/mL, while the total flavonoids ranged from 64.94 ± 0.61 to 88.89 ± 1.76 µg EQ/mL. The antioxidant activity, determined by the ABTS method, showed values ​​between 87.5% ± 0.23 and 95.13% ± 0.4, while, by the DPPH method, the values ​​ranged from 59.15% ± 1.63 to 65.94% ± 0.08. In general terms, the substrates produced mushrooms with a satisfactory quantity of physicochemical and nutritional components. However, there was a direct relationship between the addition of banana leaves and the subtle reduction in the nutritional profile. Furthermore, in the chemical characterization, the banana leaves interfered only with the flavonoids, which did not impact the high antioxidant activity demonstrated. Therefore, the small difference makes it possible to use the substrates in isolation or in combination.