Effects of different agro-industrial waste as substrates on proximate composition,metals, and mineral contents of oyster mushroom (Pleurotus ostreatus)

The use of agro-industrial waste as substrates for mushroom cultivation is considered a promising management strategy for reducing and valorising these wastes, simultaneously reducing the cost of mushroom cultivation. In this study, oyster mushroom Pleurotus ostreatus were cultivated on twelve substrates composed of either tea waste, lime sawdust, alder sawdust, hornbeam sawdust/shaving, wheat stalk-straw, wheat bran or their composite to determine the proximate composition and accumulation of thirteen elements in their fruiting bodies. The proximate composition of P. ostreatus did not show a significant difference, regardless of the employed substrate. (one-way manova ; F_{(66, 107)} = 1.329, Wilk’s λ = 0.041, P > 0.05). However, their chemical element contents show a statistically significant difference (one-way manova ; F_{(132, 418)} = 32.163, Wilk’s λ = 0.000, P < 0.05). These results were supported by discriminant function and principal component analyses. The highest mean concentrations of six of twelve elements (i.e., Ca, Mg, Na, Zn, Cd and Cr) were recorded in P. ostreatus cultivated on the lime-sawdust substrate. Three health indices viz., estimated daily intake, target hazard quotient (THQ) and total THQ were applied to determine the risk to human health via the consumption of P. ostreatus, suggesting that they are safe for human consumption.     

Variation in content of tyramine,histamine, 2-phenylethylamine,tryptamine and their precursor amino acids in a Chardonnay wine by using different commercial active dry yeasts and nitrogen sources

Wine is a fermented beverage that could be affected by high concentrations of biogenic amines, thus altering organoleptic and health properties. In this work, the capacity of different selected yeast strains regarding to affect the content of tyramine, histamine, 2-phenylethylamine, tryptamine and their precursor amino acids (pAA) during fermentation has been described. Overall, biogenic amines (BAs) and pAA contents appeared significantly related both to the strain and to the nutrient supplementation applied. Among BAs, without and (with) nitrogen source addition, the concentrations covered a range between 0.1 and 9.5 (0.1–10.3) mg L⁻¹ for tyramine; 0.1 and 4.4 (0.1–4.6) mg L⁻¹ for histamine; 0.4 and 1.1 (0.4–1.4) mg L⁻¹ for 2-phenylethylamine; and 0.02 and 0.14 (0.01–0.12) mg L⁻¹ for tryptamine, respectively. Considering that also wine yeast species are responsible for BAs formation, the evidence from fermentation trials underlined the relevance of a careful choice of ADY strains and nitrogen sources in the management of alcoholic fermentation in wine.