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Starch modification studies have been carried out to overcome the shortcomings of native starches and to increase the usefulness of starch for industrial applications. The thermal, structural and pasting properties of starch from chestnut fruits ( Castanea sativa, Mill), which were modified by mixtures of water-HCl, methanol-HCl and ethanol-HCl at different concentrations, were assessed. The thermogravimetry (TG) results showed that the chestnut starches had lower thermal stability when compared to starch from other botanic sources; however, after treatment, this stability increased. The differential scanning calorimetry results confirmed the gradual degradation of the amorphous areas of the starch granules by the acid-water mixture, which was enhanced by acid-ethanol treatment, leading to more crystalline residues that needed higher enthalpy to gelatinise. Using X-ray powder diffractometry, it was possible to observe a C-type starch and a reduction in relative crystallinity values when compared to native starch. In addition, the pasting viscosities decreased in all the modified starches, as was expected. However, obvious defects or signs of damage on the surface of the granules were not observed after treatment. This study is helpful to better understand the relationships between structure and functional properties in relation to the eventual industrial application of chestnut starches. [ABSTRACT FROM AUTHOR]

Introduction. Unconventional starch sources are interesting industrial alternatives, each presenting different properties. Thermal, morphological, structural and pasting characteristics from ginger starch were investigated in this study. Materials and methods. Ginger starch was extracted by aqueous process and its characteristics were analysed by thermogravimetry/derivative thermogravimetry, differential scanning calorimetry, rapid viscoamylographic analysis, scanning electron microscopy and X-ray powder diffractometry. Results and discussion. Similar thermal stability and three mass losses were found for the starch samples. Higher transition temperatures and enthalpy of gelatinisation were found for commercial sample, which was related to the longer amylopectin chains due to B-type crystallinity. Starch obtained from "doce" ginger showed the highest peak and final viscosities associated with the lowest pasting temperature, which is a interesant result for food applications, in addition to the low energy required for gelatinisation. An ellipsoidal shape and no fissures on the surface of the granules were visuallised by microscopy, and the diameter and the commercial sample had the smallest granules. A-type diffraction was obtained for doce and "forte" ginger starches, while commercial starch presented B-type pattern. The highest relative crystallinity was exhibited by the "forte" ginger starch. Conclusions. Commercial samples presented differences compared to known varieties. Interesting properties were found, highlighting the "doce" ginger variety. [ABSTRACT FROM AUTHOR]

Production of tablets in pharmaceutical industry often is required to mixture the active ingredient (drug) with an inert material. Starch is shown as a good alternative material to be used as excipient. Thus, in this investigation the techniques: thermogravimetry and derivative thermogravimetry (TG/DTG), differential scanning calorimetry (DSC as well as thermomicroscopy were performed with aim to verify existence of interactions between aceclofenac (2-[2-[2-[(2,6-dichlorophenyl)amino]phenyl]acetyl]oxalacetic) with regular maize starch and waxy maize starch. Binary and physical mixtures of aceclofenac and starch in ratios 2:1, 1:1 and 1:2 (drug:starch) studied by the instrumental techniques showed that no interactions occurs between the drug and starches in any ratio, being maintained the properties of aceclofenac. [ABSTRACT FROM AUTHOR]