EVALUATION OF POTATO PEEL EXTRACT AS A SOURCE OF ANTIOXIDANT AND ANTIMICROBIAL SUBSTANCES

Antioxidant and antimicrobial substances were extracted from potato peels by using different solvents (water and both methanol and ethanol at a concentration of 80 and 100 %). The potato peel extracts were evaluated for yield extract, antioxidants activity, total phenols and total flavonoids. The best extracts were selected for their efficacy as an antioxidant and antimicrobial. The proximate composition of dried potato peels indicated that total carbohydrates (65.47 %) were the major compound, while total lipids (2.60 %) were the minor compound. Potato peel methanol extract at concentration 80 % (PPME) had higher yield extract (10.42 %), total phenols (3.78 mg GAE g-1 DW), total flavonoids (0.13 mg Rutine g-1 DW) and antioxidants activity (80.86 %) than other solvent extracts. The vanillic (176.64 µg/ l) and hesperdin (6058.52 µg/ l) were the most abundant phenolic and flavonoid compounds, respectively in PPME. Induction period (using Rancimat instrument) was increased from 5.95 hr for sunflower oil free from PPME to 10. 9 and 11 hr for sunflower oil containing 200 and 400 ppm of PPME, respectively, comparing with 14 hr for sunflower oil containing 200 ppm of butyl hydroxyl toluene (BHT). PPME at 400 ppm was more effective in inhibiting of both gram-positive and gram-negative bacteria and C. albicans than ampicillin.