Compostos bioativos e caracterização de sementes de frutas tropicais

Abstract

The disposal of waste generated by the food processing industry brings negative impacts to the environment. Therefore, the knowledge of the potential of this waste has been increasingly observed. This study aimed to characterize and evaluate the viability of extracting bioactive substances in tamarind (Tamarindus indica Linn.), mango (Mangifera indica Linn.) and pitanga (Eugenia uniflora Linn.) seeds. The seeds were analyzed for percent composition, mineral content, starch, pectin, total phenolics, anthocyanins, carotenoids and antioxidant activity by DPPH (2,2-diphenyl-1-picrylhydrazyl). Carbohydrates are the majority fraction in the seeds, with 72.06%, 80.32% and 86.02% for tamarind, mango and pitanga, respectively. The energy values observed were 423.42 kcal/100g for tamarind seeds, 430,93 kcal/100g for mango and 378,86 kcal/100g for pitanga. Seeds are rich in phenolic compounds (122.29 mg EAG/g for tamarind, 167.51 mg EAG/g for mango and 268.29 mg EAG/g for pitanga), magnesium and copper. Due to the high anthocyanin content, the tamarind seed was chosen for the extraction process, using simplexcentroid design, with solvents considered to be less aggressive to the environment and to human health (water, ethanol and isopropanol) at three temperatures (25 °C, 35 °C and 55 °C); time (4 hours) and seed:solvent (1:5) ratio were previously fixed. Through this design, an increase in the total phenolic extraction of 20 m g/100 g was observed when isopropanol was used as a pure solvent at 35 °C to 1100 mg/100 g using the water:isopropanol mixture at 55 °C. The anthocyanin content of 1.11 mg/100 g in the extract obtained from water as a pure solvent at 35 °C, reached 6.89 mg/100 g when water and ethanol were used at 25 °C. The percentage of DPPH radical sequestration of the extracts ranged from 0.4% with isopropanol at 25 °C, to 91.3% in the extract obtained at 55 °C from the water/isopropanol mixture. The simplex-centroid design proved to be an efficient way to optimize the extraction process of total phenolics, anthocyanins and antioxidant activity.