LYOPHILIZED JAMBU (SPILANTHES OLERACEA L.) LEAF POWDER: SOURCE OF BIOACTIVE COMPOUNDS TO POTENTIAL FOOD APPLICATION

Spilanthes oleracea is a plant popularly consumed in North of Brazil as ingredient (cooked leaves) in regional foods. S. oleracea leaves presents good amounts of fibers, carbohydrates, minerals and spilanthol, a bioactive compound that possess anesthetic and anti-inflammatory characteristics. Few studies are dedicated to determining their chemical, antioxidant properties and thermo behavior. In this context, the aim of this study was to obtain and characterize a lyophilized leaf powder from Spilanthes oleracea (LPSO), as a source of bioactive substances and potential food application. The fresh leaves were sanitized, milled and lyophilized to further analyses. The microstructure of LPSO was visualized by scanning electronic microscopy (SEM). Flavonoids, ascorbic acid and total polyphenols from LPSO were quantified. Total antioxidant activity (TAA) was determined by ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)) and DPPH (2,2-diphenyl-1-picrylhydrazyl) assays. The chemical composition and thermo behavior from LPSO were investigated by infrared spectroscopy (FTIR) and thermogravimetric analysis. The SEM micrographs from LPSO showed irregular structures from the milled leaves covered with few starch granules. Bioactive contents of flavonoids, ascorbic acid and polyphenols were 235.5 mg/mL, 18.0 mg/100g and 2480.5 mg Eq. of gallic acid/100g, respectively. A great TAA was found in LPSO. ABTS and DPPH assays determined 13.65 μmol Trolox.g-1 and 1.35x10-1 g/g (EC50) of TAA, respectively. The FTIR spectrum reveled high intensity bands at 3400 cm-1, 1640 cm-1, 1385 cm-1, 1107 cm-1 and 1063 cm-1, related to O−H, C−O−H, C−H and C−O−C vibrations, which are associated to typical bands of cellulose and organic acids. The thermo behavior from LPSO shows an initial degradation temperature at 222 °C and peak temperature of 278 °C. These results indicate a great potential of LPSO utilization into food formulations as a natural source of bioactive compounds, fibers and carbohydrates which can contribute to stabilize and to insert functional properties in processed foods.