Effect of substrate and harvest on the amino acid profile of Oyster mushroom (Pleurotus ostreatus)

Oyster mushrooms (Pleurotus ostreatus (Jacq.: Fr.) Kumm.) were grown in either maize or pumpkin straw. Samples were taken for each one of the three harvests and analyzed for total nitrogen (N) content and amino acids profile. The substrate had no effect (P>0.05) on N content and amino acid profile of the fruits. However, N (g/100 g dm) increased (P<0.05) from 4.13 g in the first harvest to 5.74 g in the third harvest. In general, the amino acids tended to be higher on the first harvest samples, but no changes were found (P>0.05) in the amino acid profile due to substrate or harvest, except for valine decreasing (P<0.05) from 3.96 to 3.15 g/16 g N. Changes in the N content of the fruit could be explained by changes in the stipe and pileus proportions as they had different N content (3.15 and 5.48±0.031 g N/100 g dm, respectively). The amino acid profile of the mushroom was adequate according to the FAO/WHO/UNU adult human amino acid requirements.