Influence of Iron Addition (Alone or with Calcium) to Elements Biofortification and Antioxidants in Pholiota nameko

Biofortification of Mushrooms: A Promising Approach

Mushrooms exhibit a broad spectrum of pharmacological activities and are widely used for medical purposes and in nutrition. Numerous bioactive metabolites are responsible for these activities. Their distribution and biological effects differ depending on the fungal species and their chemical composition. Biofortification is a sustainable process that aims to improve the nutritional profile of food crops, as most of them are low in key nutrients. This review aims to delve into the process of fungal biofortification and review the most commonly used elements and species. Through biofortification, it is possible to combat hidden hunger, which affects as many as 2 billion people worldwide. "Hidden hunger" is a phenomenon in which the organism lacks the minerals and vitamins needed for development, growth, and good overall health. Mushrooms are increasingly being considered for biofortification due to their ability to accumulate various elements (both micro- and macroelements).

Assessment of nutrient contents and bio-functional activities of edible fungus bio-fortified with copper, lithium and zinc

Bio-enrichment of edible mushrooms is an outstanding strategy to deliver essential nutrients to human. In this study, an edible fungus; Pleurotus pulmonarius was cultivated on spent mushroom substrate (SMS) supplemented with copper, lithium, and zinc. Proximate and mineral analysis of cultivated mushroom was determined using methods of AOAC. Antimicrobial activity of cultivated mushroom was assessed against microorganisms using agar well diffusion. Antioxidant property of mushroom was assessed against free radicals. Similar (p ≤ 0.05) protein contents of 18.93%, 18.80% and 17.90% were respectively obtained in P. pulmonarius biofortified with Cu + Li + Zn, Cu + Zn and Zn. Crude fibre in element fortified-mushroom ranged from 9.02 to 10.11%, while non-fortified mushroom was 8.66%. Copper content of P. pulmonarius fortified with Cu alone and Cu + Zn were 96.12 mg/100 g and 98.09 mg/100 g, respectively. Mushroom fortified with Zn has the highest zinc content of 520.15 mg/100 g. Mushroom fortified with Li and Li + Zn have a similar (p ≤ 0.05) Li content of 106.02 mg/100 g and 104.30 mg/100 g, respectively. Extract from mushroom-fortified with copper has the highest zone of inhibition (15.1 mm) against Klebsiella pneumoniae at 1.0 mg/ml. Mushroom fortified with Cu + Li + Zn and Li + Zn, respectively have similar (p ≤ 0.05) scavenging activities of 79.10 and 81.0% against DPPH. Mushroom fortified with Zn or Zn + Cu enhanced the growth of Lactobacillus acidophilus and Lactobacillus plantarum. Antimicrobial, antioxidant and prebiotic activities of fortified-mushroom could be attributed to arrays of phytochemicals and bio-accumulated elements. Hence, bio-fortified mushrooms can be used as functional foods and as biopharmaceuticals to treat ailments associated with nutrient deficient.

Biofortification of Three Cultivated Mushroom Species with Three Iron Salts—Potential for a New Iron-Rich Superfood

Mushrooms fortified with iron (Fe) can offer a promising alternative to counter the worldwide deficiency problem. However, the factors that may influence the efficiency of fortification have not yet been fully investigated. The aim of this study was to compare the effects of three Fe forms (FeCl₃ 6H₂O, FeSO₄ 7H₂O, or FeHBED) in three concentrations (5, 10, or 50 mM) for three mushroom species (Pleurotus eryngii, P. ostreatus, or Pholiota nameko) on their chemical composition, phenolic compounds, and organic acid production. The most effective metal accumulation of all the investigated species was for the 50 mM addition. FeCl₃ 6H₂O was the most favorable additive for P. eryngii and P. nameko (up to 145 and 185% Fe more than in the control, respectively) and FeHBED for P. ostreatus (up to 108% Fe more than in control). Additionally, P. nameko showed the highest Fe accumulation among studied species (89.2 ± 7.51 mg kg⁻¹ DW). The creation of phenolic acids was generally inhibited by Fe salt supplementation. However, an increasing effect on phenolic acid concentration was observed for P. ostreatus cultivated at 5 mM FeCl₃ 6H₂O and for P. eryngii cultivated at 5 mM FeCl₃ 6H₂O and 5 mM FeSO₄ 7H₂O. In the case of organic acids, a similar situation was observed. For P. ostreatus, FeSO₄ 7H₂O and FeHBED salts increased the formation of the determined organic acids in fruiting bodies. P. eryngii and P. nameko were characterized by a much lower content of organic acids in the systems supplemented with Fe. Based on the obtained results, we recommend starting fortification by preliminarily indicating which form of the element is preferred for the species of interest for supplementation. It also seems that using an additive concentration of 50 mM or higher is most effective.

Accumulation of Selected Metal Elements in Fruiting Bodies of Oyster Mushroom

The species Pleurotus ostreatus is a commercially, gastronomically, and biotechnologically important fungus. Its strain variability has been little researched. The study provides an evaluation of 59 oyster mushroom production strains in terms of the ability to accumulate selected metals in the cap and stipe. The fruiting bodies were grown under identical model conditions on straw substrate. Metal concentrations (ET-AAS) in dry fruiting bodies ranged in values 1.7-22.4 mg kg-1 for Al, 2.6-9.7 mg kg-1 Ba, 199-4560 mg kg-1 Ca, 1.7-12.0 mg kg-1 Cu, 12-120 mg kg-1 Fe, 16,000-49,500 mg kg-1 K, 876-2400 mg kg-1 Mg, 0.39-11.0 mg kg-1 Mn, 46-920 mg kg-1 Na and 11-920 mg kg-1 for Zn. More Cu, Fe, K, Mg, Mn, Zn accumulated in the cap, while in the stipe Ba was amassed. No significant difference was found between Al, Ca and Na between the accumulation in the cap and the stipe. Furthermore, the dependence of metal uptake from the substrate depending on the fortification of the substrate was confirmed. Statistically significant (p < 0.05) synergistic relationships were shown in pairs Al and Ba, Al and Fe, Ba and Na, Ba and Ca, Ca and Na, Cu and Fe, Fe and Mn, Fe and Zn, K and Mg, K and Mn, K and Zn, Mg and Mn, Mg and Na, Mg and Zn and Mn and Zn in the substrate without the addition of sodium selenate to the substrate. Altered relationships were observed after the application of sodium selenate to the substrate, synergism of Se and Ni, Se and Co and Se and Hg, Cu and Mn, Cu and Fe, Zn and Co, Zn and Ni, Zn and Hg, Mn and Fe, Mn and Cr, Co and Ni, Co and Hg, Ni and Hg, Pb and Cd. The findings of the study may help in the selection of production strains with hypercumulative properties for a particular metal and subsequent use in the addition of fortified fruiting bodies (e.g., with Zn). Based on the study the strains less sensitive to the accumulation of hazardous metals is possible to select for large-scale production, which is important from the perspective of food safety.