EVALUATION OF THE MICROBIOLOGICAL SAFETY AND ANTIOXIDANT ACTIVITY OF BEETROOT LEAVES (BETA VULGARIS) STORED FOR A TWO YEARS PERIOD IN GELATIN CAPSULES

In Brazil, parts of fruits and vegetables are normally uneaten. Leaves and stems are usually discarded, even presenting high content of nutrients and bioactive compounds. For example, beetroot leaves show high amount of phenolic compounds wich have effects on biological activities, that were validated in tests with in vivo and in vitro models. The present study aims to evaluate the microbiological safety, the concentration of phenolic compounds and the antioxidant potential of freeze-dried beetroot leaves capsules stored for two years at room temperature. In order to perform the microbiological safety analysis, experiments were conducted for coliform determination (multiple tube technique), coagulase-positive staphylococci (Baird Parker and coagulase test with rabbit plasma) and Salmonella (BAM/FDA procedure, 2007). A hydroalcoholic extract of freeze-dried beetroot leaves was prepared to determine the concentration of total phenolics through Folin-Ciocalteu method and the antioxidant potential was determinated through ABTS and FRAP methods. The material in the capsule showed results according to the RDC resolution parameters nº 12, which all the analyzed microorganisms were below the detection limits of the methods used. Regarding the total phenolic compounds, the extracts showed a value of 13.62 ± 0.76 mg GAE/g. The antioxidant potential ABTS and FRAP were, respectively, 26.29 ± 0.4 mg Eq Trolox/g, 120.47 ± 7.31 µM eq SF/g (mean/standard deviation). The results suggest that freeze-dried beetroot leaves capsules can be stored at room temperature for at least two years keeping an adequate microbiological safety and preserving the bioactive compounds, what can bring health benefits if consumed with healthy eating habits and lifestyle.