Effects of whey permeate medium on mushroom mycelia composition and antioxidant properties

The effects of whey permeate (WP)-based medium and harvesting time on the growth of Lentinus edodes and Pleurotus ostreatus mycelia were studied. Mycelia were grown on WP-based medium with lactose content of 4.5% or defined synthetic medium at 25 +/- 1 °C, and harvested after 5, 10, 15, or 20 days of fermentation for L. edodes and 4, 8, 12, or 16 days for P. ostreatus.;Biomass production, crude water-soluble polysaccharide (WSP), and ash content of mycelia were determined. Harvesting time and the type of media interact to alter the chemical content of mycelia. Mycelia grown in whey permeate had greater (P < 0.05) crude WSP and ash contents than mycelia grown in the synthetic media. A maximum production of crude WSP from mycelia grown on the WP-based media was obtained on day 10 (4.1 x 102 +/- 71 mg WSP/g dried mycelia) for L. edodes and on day 12 (5.9 x 102 +/- 38 mg WSP/g dried mycelia) for P. ostreatus. The highest values in ash content were obtained from L. edodes mycelia harvested on day 20 (18 +/- 3%) and from P. ostreatus on day 8 (14 +/- 1%).;Total antioxidant capacity and phenolic content were determined for L. edodes. Both methanol and water extracts were found to exhibit high free radical scavenging capacity. The harvesting time was found to contribute to most of the variability in the free radical scavenging capacity. High levels of antioxidant capacities (0.28 +/- 0.03 and 0.29 +/- 0.06 mmol Trolox antioxidant equivalent/g dry wt for methanol and water extracts, respectively) were observed in mycelia grown on whey permeate and harvested on day 10. The overall means of total phenolic contents of mycelia grown in whey permeate were 5.9 +/- 0.5 and 6.2 +/- 0.6 mg gallic acid equivalents/g dried mycelia for methanol and water extracts, respectively.;In conclusion, this research suggests that whey permeate (4.5% lactose) was more favorable than control media in the production of crude WSP. High levels of antioxidant capacity could be obtained in mycelia grown on whey permeate.