Supplementation with Magnesium Salts—A Strategy to Increase Nutraceutical Value of <i>Pleurotus djamor</i> Fruiting Bodies

• Main Authors: Piotr Zięba, Agnieszka Sękara, Emilia Bernaś, Agata Krakowska, Katarzyna Sułkowska-Ziaja, Edward Kunicki, Małgorzata Suchanek, Bożena Muszyńska
• Format: Article
• Language: English
• Published: MDPI AG 2021-05-01
• Series: Molecules
• Subjects: pink oyster; <i>Pleurotus djamor</i>; functional food; biofortification; magnesium
• Online Access: https://www.mdpi.com/1420-3049/26/11/3273

The use of substrates supplemented with minerals is a promising strategy for increasing the nutraceutical value of <i>Pleurotus</i> spp. The current research was performed to analyze the effect of substrate supplementation with magnesium (Mg) salts on the Mg content, biomass, and chemical composition of pink oyster mushroom (<i>Pleurotus djamor</i>) fruiting bodies. Before inoculation, substrate was supplemented with MgCl₂ × 6 H₂O and MgSO₄, both salts were applied at three concentrations: 210, 420, and 4200 mg of Mg per 2 kg of substrate. The harvest period included three flushes. Substrate supplementation with 4200 mg of Mg caused the most significant decrease in mushroom productivity, of about 28% for both Mg salts. The dry matter content in fruiting bodies was significantly lower in the treatment in which 210 mg of Mg was applied as MgSO₄ in comparison to the control. Supplementation effectively increased the Mg content in fruiting bodies of <i>P. djamor</i> by 19–85% depending on the treatment, and significantly affected the level of remaining bioelements and anions. One hundred grams of pink oyster fruiting bodies, supplemented with Mg salts, provides more than 20% of the Mg dietary value recommended by the Food and Drug Administration (FDA); thus, supplementation can be an effective technique for producing mushrooms that are rich in dietary Mg. Although <i>P. djamor</i> grown in supplemented substrate showed lower productivity, this was evident only in the fresh weight because the differences in dry weight were negligible. Mg supplementation increased the antioxidant activity of the fruiting bodies, phenolic compounds, and some amino acids, including L-tryptophan, and vitamins (thiamine and <span style="font-variant: small-caps;">l</span>-ascorbic acid).