Nutraceutical potential, antioxidant and antibacterial activities of Terfezia boudieri Chatin, a wild edible desert truffle from Tunisia arid zone

Nutritional composition, antioxidant and antibacterial properties of Terfezia boudieri Chatin, a desert truffle largely distributed in Southern Tunisia were evaluated. Carbohydrates were the most abundant macronutrients (62.03 g/100 g) followed by proteins (26.12 g/100 g) in T. boudieri truffle (dry mass). The ash content was 4.49 g/100 g dry mass and potassium, phosphorus, iron, and calcium were found to be particularly abundant in T. boudieri. The fat content of the truffle was 8 g/100 g dry mass, characterized by its higher content of the essential linoleic acid (n-6) (54.18%). Eight volatile compounds were identified by GC and GC/MS and they were dominated by fatty acids. The results of ascorbic acid, total carotenoids and total anthocyanins expressed on a truffle dry mass were 12.20 mg/100 g, 1.43 mg/100 g and 35.40 mg/100 g, respectively. The methanolic extract, containing the highest amounts of phenolics and flavonoids, displayed the highest DPPH radical-scavenging activity (IC50 = 0.20 mg/ml) and the lipid peroxidation inhibitory activity (IC50 = 0.36 mg/ml). Furthermore, the truffle extracts were tested for their antibacterial activity against seven species of bacteria. The methanolic extract also exhibited remarkable inhibitory activity on the tested strains, which minimum inhibitory concentration values ranged from 0.25 to 1.3 mg/ml.