Assessment of proximate composition, mineral element profile and antioxidant properties of the edible oyster mushroom grown in Bangladesh

Abstract Mushrooms have been considered as a therapeutic and nutrient-rich foods in numerous countries for years due to their significant levels of nutritional components, vitamins and antioxidants. This study aimed to assess the nutrient content, mineral profile and antioxidant properties of eight different kinds of oyster mushrooms (Pleurotus sp.) cultivated in Bangladesh. The mushrooms were analyzed for their moisture content, carbohydrates, proteins, fats, fibers, ash, vitamin A, and vitamin C. The mineral profile included sodium, potassium, calcium, and iron, as well as heavy metals. Antioxidant activities were evaluated through various methods, including phenolic, flavonoid and tannin content, total antioxidant activity, and DPPH (2,2-diphenyl-1-picryl-hydrazyl) scavenging capacity. The findings revealed that the mushrooms under investigation were high in carbohydrate (ranges between 45.25 and 63.22 g/100 g), protein (23.48–33.16 g/100 g) and dietary fiber (42.87–52.31 g/100 g). The total ash content was ranged from 7.28 to 9.41 g/100 g and vitamin C content was 0.020–0.416 mg/100 g. Interestingly, all of the mushrooms had a lower fat content (0.91–2.6%). The mineral profile indicated the presence of varying concentrations of essential elements. Hazardous heavy metals, such as Cd and Cr were not detected in the mushroom sample, while As and Pb were detected but lower than the tolerance levels. The oyster mushrooms exhibited high levels of phenolic, flavonoid, and tannin contents, as well as significant antioxidant capacity. A methanol extract of the oyster mushrooms exhibited scavenging activity against DPPH in a dose dependent manner with the highest capacity (75.4%) obtained at a concentration of 0.2 mg/ml. Our result suggests that these studied oyster mushrooms could be a good source of nutrition and antioxidants, which could be used as functional foods.