Extração e purificação do amido da raiz de Mirabilis jalapa

Abstract

The popular and ornamental plant Mirabilis jalapa (from Nyctaginaceae Family) is originary from Latin America and planted in several countries around the world. It hás been characterised by a number of important properties due its chemical compounds which have been isolated and used in medicine. The main properties described are: from leaves (hypoglicemic, anti-viral, antinociceptive and anti-inflamatory activities), from flowers (antispasmodic activity), from tubers and roots (anti-oxidative, antibacterial, antifungal, anti-histaminic, anti-hyperlipidemic and hypoglicemic activities). The roots contain, in addition to the mentioned compounds, a large amount of starch, which also has small particle size as well as those obtained from the seeds. So, the main objective of this investigation was to purify the starch, with small granule size, obtained in the extraction process of Mirabilis jalapa roots. After, the starch was characterised by the techniques: thermogravimetry, derivative thermogravimetry (TG/DTG), simultaneous thermogravimetry-differential scanning calorimetry (TGDSC), Field-emission-gun Scanning Electron Microscopy with energy-dispersive spectroscopy (FEG-SEM-EDS) and by X-ray Diffractometry by powder method (XRD). The EDS results shown that before purification, this starch has large amount of raphides (calcium oxalate) confirmed by qualitative analysis and quantified by TG/DTG and TG-DSC (45,12%). After purification with 2.0 mol l-1 of HCl the calcium oxalate was not present and the shape and size of starch granules were maintained (average diameter 1-5 mm) as observed by SEM.