Acta Scientiarum Polonorum Technologia Alimentaria

Background. The present work compares the content of basic chemical constituents as well as amino acids in frozen Pleurotus ostreatus (Jacq.: Fr.) Kumm. and Agaricus bisporus (Lange) Sing. mushrooms.

Material and methods. The material investigated comprised of frozen P. ostreatus and A. bisporus mushrooms after 8 months’ storage, having been soaked and blanched in a solution 0.5% citric acid, 0.5% lactic acid and 0.1% L-ascorbic acid prior to freezing.

Results. Compared with frozen A. bisporus, frozen P. ostreatus contained significantly higher levels of total carbohydrates (32% higher), raw fat (38%) and most endogenous
(6-163%) and exogenous (10-200%) amino acids, but lower levels of ash (45% lower), total nitrogen (50%) and protein nitrogen (40%). In both species, asparagine and glutamine were the most abundant endogenous amino acids (respectively 10-12% and 12-19% of total amino acids), and leucine and lysine the most abundant exogenous amino acids (7-9% and 6-7%). The least abundant were glycine and proline (both 5%), and cysteine and methionine (1% and 2%).

Conclusions. Frozen mushrooms of both species are potentially good sources of protein in the diet as no limiting amino acids were found when compared with the FAO/WHO reference protein pattern. However, it is important to determine the digestibility of protein in the mushrooms model studies using animals and people. The conversion coefficient from total nitrogen to protein was 5.23 in P. ostreatus and 2.46 in A. bisporus.