Tirmania pinoyi: Chemical composition, in vitro antioxidant and antibacterial activities and in situ control of Staphylococcus aureus in chicken soup.

Abstract: Desert truffle, Tirmania pinoyi (Maire) Malençon from Libya was chemically characterized in nutritional value, primary and secondary metabolites. Antioxidant (scavenging activity, reducing power and inhibition of lipid peroxidation) and antibacterial activity of its methanolic extract alone and in combination with potassium metabisulfite (E224) were evaluated under in vitro conditions. Furthermore, the effect of the extract on the control of Staphylococcus aureus was examined in a contaminated soup under in situ conditions. T. pinoyi was shown to be rich in carbohydrates (82.60g/100g dw) and proteins (8.06g/100g dw), being identified four free sugars (rhamnose, fructose, trehalose and mannitol) and three tocopherol isoforms (β-, δ- and γ-tocopherols). Oleic (32.29%), linoleic (29.72%) and palmitic (27.97%) acids were the main fatty acids. p-Hydroxybenzoic (300.65μg/100g dw) and cinnamic (8.30μg/100g dw) acids were quantified, as also four organic acids: quinic (0.83g/100g dw), malic (0.35g/100g dw), fumaric (0.05g/100g dw) and citric (1.26g/100g dw) acids. The methanolic extract of the mushroom showed in vitro antioxidant and antimicrobial activities. Sterilized distillated water containing 0.02% Tween 80 proved to be the most convenient solvent for in situ antimicrobial activity; the extract successfully inhibited the growth of S. aureus in chicken soup in a dose dependent manner. [Copyright &y& Elsevier]