CHEMICAL COMPOSITION, BIOACTIVE COMPOUNDS AND ANTIOXIDANT ACTIVITY OF THE ORGANIC MINT-PEPPER LEAF.

Introduction A growing activity in the world is the production of vegetables of the organic genus. Among these vegetables is Mentha piperita L. or peppermint belonging to the Lamiaceae family which is widely used as food ingredients and herbal teas. Peppermint, commonly used in several preparations, is an excellent source of phenolic compounds, known as antioxidants. Objective The objective of the present study was to analyze the centesimal composition, vitamin C content, total phenolics, total flavonoids and antioxidant activity (in vitro) in leaves of organic peppermint. Methods The samples of peppermint organic were purchased in a specialized establishment selling organic food in Teresina-PI. For the acquisition of food was used as a selection criterion to the presence of the seal of identification of SISORG. To obtain the centesimal composition, moisture was determined by oven drying at 105 ° C until constant weight. The ash content was determined after calcination of the samples in a muffle oven at 550 ° C. The concentration of proteins was determined by the Macro-Kjeldahl method, with conversion factor of 5.75 and the lipid content by hot flashing, using the solvent hexane in Soxhlet apparatus. The carbohydrate content was calculated by difference. For the vitamin C content, the Tillmans method was used, which is based on reducing the dye sodium salt of 2,6-dichlorophenolindofenol by an acidic solution of vitamin C. For the determination of the bioactive compounds, the extract was elaborated with 80% acetone, resulting in the best extraction yields. The total phenolics, total flavonoids and antioxidant activity in vitro, using the DPPH radical, were determined by spectrophotometric method. Results and Discussion From these analyzes a percentage of 78% moisture, 1.7% ash, 1.5% lipids, 0.32% protein and 17.68% carbohydrates it was obtained. The vitamin C content determined was 58.8 mg/g. In the bioactive compounds analysis, 123.29 mg/g of total phenolics, 266.15 mg/L of total flavonoids, 1,23 mg/ml of antioxidant activity were observed. In view of the above, it can be verified that the two main components of peppermint are water and carbohydrates, which is directly related to its low caloric value. In the study by Fernandes (2010), the vitamin C content of different plants of the family Lamiaceae, such as Mentha pulegium, Thymus pulegioides and Thymus mastichina, was found values of 7.90 mg/g, 5.95 mg/g and 12.87 mg/g, respectively, values lower than the vitamin C content present in mint. In relation to the contents of phenolic compounds, it was observed significant contents of total phenolics and flavonoids. These compounds contribute in the fight against free radicals and, consequently, in the prevention of non-transmissible chronic diseases. In the study done by Morais et al. (2009), in which the antioxidant action of mint tea was evaluated, the value determined was 17.40 mg/mL, which is higher than the present study. This result can be justified due to the cellular matrix of the food that is altered with the thermal processing. Conclusions That mint possesses desirable attributes such as high content of bioactive compounds, promoting mainly increased antioxidant activity of preparations.