Hanna Staroszczyk

Interactions of fish gelatin and chitosan in uncrosslinked and crosslinked with EDC films: FT-IR study

Films based on fish gelatin, chitosan and blend of fish gelatin and chitosan before and after cross-linking with EDC have been characterized by FT-IR spectroscopy. The FT-IR spectrum of fish gelatin film showed the characteristic amide I, amide II and amide III bands, and the FT-IR spectrum of chitosan film confirmed that the polymer was only a partially deacetylated product, and included CH3-C=O and NH2 groups, the latter both in their free -NH2 and protonated -NH3(+) form. Analysis of FT-IR spectra of two-component, fish gelatin-chitosan film revealed the formation not only of hydrogen bonds within and between chains of polymers, but also of electrostatic interactions between -COO(-) of gelatin and -NH3(+) of chitosan. Modification with EDC provided cross-linking of composites of the film. New iso-peptide bonds formed between activated carboxylic acid groups of glutamic or aspartic acid residue of gelatin and amine groups of gelatin or/and chitosan.

Microwave-assisted solid-state sulphation of starch

Abstract Starch was sulphated with pyridine.SO3 complex in the microwaveassisted solid state processes in multimodal microwave oven and, for comparison, also on convectional heating blends of solid reagents. Starch was less hydrolysed in microwave-assisted reactions. The degree of the esterification of the sulphuric acid anhydride depended to a lesser extent on the reaction time and the power applied, and more essentially on the reagent ratio, that is, dose of the sulphating agent. Its higher doses favoured depolymerization and esterification leading to diesters, that is, crosslinking.

Facile synthesis of potato starch sulfate magnesium salts

Abstract Potato starch blended with MgSO4 and conc. H2SO4 - Mg(HSO4)2 generated in situ - forms directly starch sulfate magnesium salts. Properties of the products depend, first of all, on whether convectional heating (60 - 70°C for 1 h) or microwave heating for either 30 min at 180 W or 5 min at 300 W is applied. Starch monoester and crosslinking diester are formed. The products are up to 95% watersoluble. They were characterized by means of thermal gravimetry and differential thermogravimetry, FTIR spectroscopy, and elemental analysis for Mg. Resulting products are potential plasticisers for cement, mortar, concrete, or other products containing hydraulic binders.

Synthesis and characterisation of starch cuprate

The cupration of granular potato starch with ammonium tetrachlorocuprate(II) was performed by a 20min lasting microwave-assisted process and by 40min convectional heating. In both cases the degree of esterification (DE) did not exceed 6.4×10(-3). A higher dose of cuprate had a positive effect on DE, regardless of whether the microwave irradiation or the convectional heating was applied, and on the thermal stability of the starch cuprate produced in the microwave-assisted way. As a result of cupration, the hydroxyl ligand of the starch d-glucose units was replaced by the chloride ligand of the tetrachlorocuprate(II) anion. In the starch cuprate formed in the microwave-assisted process, the cuprate anion additionally coordinated water molecules. The cupration reduced starch crystallinity, as indicated by X-ray diffractometry and differential scanning calorimetry.

Starch-metal complexes and metal compounds: Starch-metal compounds

Recently, metal derivatives of starch evoked considerable interest. Such metal derivatives can take a form of starch compounds bearing metal atoms and metal carrying moieties either covalently bound or complexed. Starch metal complexes may have a character of either Werner, inclusion, sorption or capillary complexes. In this publication, preparation, structure, properties and numerous current and potential applications of those compounds as well as benefits resulting from the application and formation of the complexes are presented.

Investigation of an elutable N-propylphosphonic acid chitosan derivative composition with a chitosan matrix prepared from carbonic acid solution

Porous chitosan composites using CO2 dissolution procedure and including water soluble N-propylphosphonic chitosan derivative (p-CHI) were obtained and characterized. In contrast to the control material, composites containing modified chitosan distinguished by a rapid moisture absorption and good adhesion to the skin. The FTIR analysis confirmed the presence of propylphosphonic group in the structure of the polymer. The porosity of the materials was in the range 55-77% and decreased with increasong amount of modified chitosan in materials. Solubility of composites was dependent on the content of p-CHI in scaffolds (40%, 25% and 15%) and reached values 11%, 9% and 6,5%, respectively. The values of other parameters like swelling degree (30g/g) good antioxidant and antimicrobial properties (almost 100% reduction of S.aureus, E.coli and C. albicans growth) and low in vitro cytotoxicity against fibroblasts were highly advantageous for possible biomedical applications of the composites.

A DSC and NMR-relaxation study of the molecular mobility of water protons interacting with chemically modified starches

Changes in the mobility of water protons in the chemically modified starches (CMS)–water system are studied by differential scanning calorimetry and NMR relaxation. The amounts of unfrozen water at negative temperatures and additional (after gelation) unfrozen for CMS are lower than those for native starch. The proton spin–spin relaxation time T2 for CMS samples, conventionally attributed to the water fraction in starch granules, decreases monotonically with increasing temperature, whereas for native starch, this dependence exhibits an extreme behavior. Studying the dispersion dependences for 7 wt % gels, which characterize the rate of chemical exchange of water protons with protons of hydroxyl groups of polysaccharides, showed the absence of this kind of dependence for the CMS studied when the instrument operated at a frequency of 20 MHz. This data indicate the significant destructive changes in the structure of the CMS.