Knowledge of the chemical composition of both wild and cultivated edible mushrooms in Ghana is limited. This study reports their nutritional value, composition in lipophilic and hydrophilic molecules, minerals and antioxidant properties. The samples were found to be nutritionally rich in carbohydrates, ranging from 64.14 ± 0.93 g in Pleurotus ostreatus strain EM-1 to 80.17 ± 0.34 g in Lentinus squarrosulus strain LSF. The highest level of proteins (28.40 ± 0.86 g) was recorded in the mentioned P. ostreatus strain. Low fat contents were registered in the samples, with Auricularia auricula recording the lowest value. High levels of potassium were also observed with the following decreasing order of elements: K > P ~ Na > Mg > Ca. High levels of antioxidants were also observed, thus making mushrooms suitable to be used as functional foods or nutraceutical sources. Furthermore, this study provides new information regarding chemical properties of mushrooms from Ghana, which is very important for the biodiversity characterization of this country.

The chemical characterization and antioxidant potential of twelve wild strains of Ganoderma sp. from Ghana, nine (LS1–LS9) of which were found growing wild simultaneously on the same dying Delonix regia tree, were evaluated. Parameters evaluated included the nutritional value, composition in sugars, fatty acids, phenolic and other organic compounds and some vitamins and vitamin precursors. Antioxidant potential was evaluated by investigating reducing power, radical scavenging activity and lipid peroxidation inhibition using five in vitro assays. Protein, carbohydrate, fat, ash and energy contents ranged between 15.7–24.5 g/100 g·dw, 73.31–81.90 g/100 g, 0.48–1.40 g/100 g, 0.68–2.12 g/100 g ash and 396.1–402.02 kcal/100 g, respectively. Fatty acids such as linoleic, oleic and palmitic acids were relatively abundant. Free sugars included rhamnose, fructose, mannitol, sucrose and trehalose. Total tocopherols, organic acids and phenolic compounds’ content ranged between 741–3191 µg/100 g, 77–1003 mg/100 g and 7.6–489 µg/100 g, respectively. There were variations in the β-glucans, ergosterol and vitamin D₂ contents. The three major minerals in decreasing order were K > P > S. Ganoderma sp. strain AM1 showed the highest antioxidant activity. This study reveals, for the first time, chemical characteristics of Ganoderma spp. which grew simultaneously on the same tree.

Pineapple rind is a by‐product of the pineapple processing industry and contains nutrients and other compounds which must be utilized as a bioresource for socio‐economic benefits while preventing the potential problems of improper agroindustrial biomass disposal methods. Pleurotus ostreatus is an edible oyster mushroom with medicinal properties and can be cultivated on various agroindustrial biomass, including sawdust containing supplements. Pineapple rind was powdered and used as a supplement of composted sawdust at 2%, 5%, 10%, 12%, 15%, and 20% (w/w) on dry weight basis. A control treatment consisted of composted sawdust supplemented with rice bran at 12% (the most utilized composition in Ghana). P. ostreatus strain EM‐1 was cultivated on these treatments. Factors investigated included the spawn run period, yield, fruiting body weight and size, biological efficiency, and nutritional composition (proximate composition and Copper, Zinc and Lead content) of fruiting bodies harvested from selected high‐yielding treatments and the control treatment. Full colonization of all treatments occurred by the 34th day of incubation. Enhanced yield, fruiting body weight and size, and biological efficiency were generally recorded with supplementation at lower concentrations (2% and 5%) compared to treatments supplemented at higher concentrations. There was also a supplement concentration‐dependent alteration of the nutritional composition of the mushroom. Powdered pineapple rind can be utilized as an organic supplement at relatively low concentrations in composted sawdust for P. ostreatus strain EM‐1 cultivation. The use of lower concentrations of powdered pineapple rind in composted sawdust is advantageous as relatively less input will be required to produce higher P. ostreatus strain EM‐1 yields. Utilization of pineapple rind for mushroom cultivation will extend the pineapple plant value chain, intensify mushroom production in a sustainable way, and minimize agricultural losses.

Changes in the heavy metal content and proximate composition during the 28 day composting of cassava peels used in the cultivation of the oyster mushrooms Pleurotus ostreatus strain EM-1 was studied. Significant dry weight variations of cellulose, hemicellulose and fat contents were observed from day 0 to 12. Decreases from day 12 to 28 had the values of 15.4, 57.6 and 56.12%, respectively, while lignin, protein and crude fibre values showed a gradual increase from day 0 to 28, with maximum values of 23.73, 49 and 73%, respectively. Cyanide content however showed a reduction from the initial 3.89 to 2.01 mg/L by day 12 and a marginal increase of 16 by day 28. This was however not detected in the mushroom harvested. The levels of heavy metal content in composted cassava peels in decreasing order was iron (Fe), manganese (Mn), zinc (Zn), lead (Pb) and copper (Cu) while that for uncomposted cassava was Fe, Zn, Pb, Mn and Cu. Levels of Cu, Mn, Pd and Zn in mushroom samples analysed were in agreement with reported values in literature. Of all the heavy metals examined, iron accumulated excessively, indicating that P. ostreatus strain EM-1 is a good bio-accumulator of Fe. Key words: Cassava, composting, heavy metals, production

Consumption patterns of mushrooms have increased in Ghana recently owing to its acknowledgement as a functional food. Different mushroom cultivation methods and substrate types have been linked to the quality of mushrooms produced, thereby affecting its pricing. A comparative regression analysis was carried out to assess the correlation of stipe lengths, cap diameters and biological efficiencies of mushroom fruit bodies of Pleurotus ostreatus cultivated on steam-sterilized and gamma-irradiated sawdust after exposure to ionizing radiations of doses 0, 5, 10, 15, 20, 24 and 32 kGy from a ⁶⁰CO source (SL 515, Hungary) at a dose rate of 1.7 kGy/h. Steam sterilization of composted substrates was also done at a temperature of 100–105 °C for 2 h. Cap diameters of the mushrooms ranged 41–71.5 and 0–73 mm for gamma-irradiated samples depending on dose and steam-sterilized composted sawdust, respectively. Stipe lengths ranged between 4.4–61 and 0–58.1 for gamma-irradiated samples depending on dose and steam-treated substrates, respectively. Total yields of P. ostreatus grown on the gamma irradiation-treated composted sawdust ranged between 8.8 and 1517 g/kg, while mushrooms from steam sterilized recorded 0–1642 g/kg. Biological efficiencies of mushrooms grown on irradiated sawdust ranged 3–93.3%, while steamed sawdust ranged 0–97%. Good linear correlations were established between the cap diameter and biological efficiency (r² = 0.70), stipe length and biological efficiency (r² = 0.91) for mushrooms cultivated on gamma-irradiated sawdust. Similarly, good correlations were established between cap diameter and biological efficiency (r² = 0.89) stipe length and biological efficiency (r² = 0.95) for mushrooms cultivated on steam-sterilized sawdust. These correlations provide the possibility to use only the cap diameter and stipe lengths to predict their biological efficiency and also use this parameter for grading and pricing of mushrooms earmarked for the consumer market.