Commercial mushrooms: nutritional quality and effect of cooking

With the aim of extending knowledge on chemical composition of mushrooms, commercial samples, widely consumed in Italy (Boletus group, Agrocybe aegerita and Pleurotus eryngii) have been examined to determine proximate composition and some components of nutritional interest such as dietary fibre, chitin, beta glucan and total phenols in raw and cooked samples. The moisture values ranged from 67.2 to 91.5 g/100 g edible weight in the raw samples, and from 71.9 to 90.4 g/100 g edible weight in the cooked samples. The lipid fraction was not relevant. Proteins, higher in Boletus group dried samples than in the other mushroom species (Agrocybe aegerita and Pleurotus eryngii), ranged from 1.5 to 7.9 g/100 g edible weight, while the ash content varied between 0.5 and 2.0 g/100 g of edible weight. Dried and re-hydrated Boletus samples showed higher levels of soluble and insoluble dietary fibre than the other samples. The amount of beta glucans varied within the same species (Boletus group samples) and represented from 2 to 13% of total dietary fibre. The chitin content ranged from 0.5 to 3.3 g/100 g edible weight. Finally, total phenols varied widely among different mushroom species, from 51.4 to 403.8 mg/100 g edible weight and from 70.4 to 301.6 mg/100 g edible weight, respectively, for raw and cooked samples. (C) 2003 Elsevier Ltd. All rights reserved.