In this work, cassava starch was modified by treatment with sodium hypochlorite (NaClO) at different concentrations (0.8, 2.0 and 5.0 % of active chlorine) and selected physicochemical properties of the oxidized starches were investigated. The native and modified samples were evaluated considering moisture, carboxyl content, apparent viscosity, susceptibility to syneresis, mid-infrared spectroscopy and crystallinity index. The treatment with NaClO resulted in alterations in carboxyl content of the oxidized starches that increased with increasing concentration of the oxidant. Oxidized starches also showed higher susceptibility to syneresis, as assessed by the release of liquid during freezing and thawing. Apparent viscosity analysis showed decrease in peak viscosity of the oxidized starches. X-ray diffractograms showed that the oxidation influenced the extent of cassava starch relative crystallinity found to lie between 34.4 % (native) and 39.9 % (2.0 % active chlorine). The infrared spectra are sensitive to structural changes on starch macromolecules and presented characteristic peaks as C-O-C of the six carbon glucose ring absorbs at 1,150-1,085 cm −1 and due to axial deformation these bands changed with the crystal structure of the starch samples.
Cynara cardunculus L. is the most widespread species of Cynara genus (f. Asteraceae). This herbaceous perennial plant is native to the Mediterranean region and invasive in other parts of the world, growing naturally in harsh habitat conditions. There are three subspecies: globe artichoke; cultivated cardoon and the progenitor of the two, the wild cardoon. The culture of Cynara cardunculus L. follows an annual growth cycle, emerging in autumn and harvesting in summer. Cynara cardunculus has been considered as a multipurpose crop due to its relevant biochemical profiles. Inflorescences have been used as food, whereas leaves are a rich source of bioactive compounds. Consequently, larger plants without spines have been selected for technological purposes. Due to its high cellulose and hemicellulose content, the lignocellulosic fraction has been used as solid biofuel, biogas and bioethanol. Both pulp fibers production and seeds oil are suitable for biodiesel production. Over the centuries, the inflorescence pistils of Cynara cardunculus L. have been widely used for cheesemaking. The present chapter gives an overview of the Cynara cardunculus L. emphasizing recent knowledge regarding the use, conservation, preparation and application of Cynara cardunculus in ovine milk cheesemaking, as well as other biotechnological applications.
RESUMO.Este trabalho descreve a montagem de um sistema de titulação fotométrica simples e de baixo custo para a determinação de ferro (III) em produtos farmacêuticos. O sistema de titulação fotométrica foi construído utilizando-se a bomba peristáltica de um espectrofotômetro convencional. O procedimento é baseado na titulação de ferro (III) com EDTA e ácido salicílico como indicador. A absorção do complexo ferro (III)-ácido salicílico foi monitorada espectrofotometricamente em 525 nm. O limite de quantificação foi de 5 g de ferro (III). O procedimento de titulação fotométrica foi aplicado para a determinação de ferro (III) em amostras contendo sulfato ferroso e hidróxido férrico polimaltosado. O procedimento mostrou sensibilidade, reprodutibilidade e precisão para a utilização em análise rotineira de ferro (III) em produtos farmacêuticos.Palavras-chave: titulação fotométrica, ferro (III), produtos farmacêuticos. ABSTRACT. Determination of iron (III) in pharmaceutical products by photometric titration.This paper describes a simple, precise and low-cost photometric titration method for iron (III) determination in pharmaceutical preparations. The photometric titration system was constructed using the peristaltic pump of a conventional spectrophotometer. The method is based on titration of iron (III) with EDTA using salicylic acid as indicator. The absorption of the iron (III)-salicylic acid complex was monitored spectrophotometrically at 525 nm. The limit of quantification was 5 g of iron (III). The photometric titration procedure was applied for the determination of iron (III) in samples of ferrous sulfate and ferric hydroxide polymaltose complex. The procedure showed sensibility, reproducibility and accuracy for use as a method for the routine analysis of iron (III) in pharmaceutical formulations.
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