Molecular Dispersion of Starch as a Crucial Parameter during Size-Exclusion Chromatography

3D printed arrowroot starch-gellan scaffolds for wound healing applications

Skin, the largest organ in the body, blocks the entry of environmental pollutants into the system. Any injury to this organ allows infections and other harmful substances into the body. 3D bioprinting, a state-of-the-art technique, is suitable for fabricating cell culture scaffolds to heal chronic wounds rapidly. This study uses starch extracted from Maranta arundinacea (Arrowroot plant) (AS) and gellan gum (GG) to develop a bioink for 3D printing a scaffold capable of hosting animal cells. Field emission scanning electron microscopy (FE-SEM) and X-ray diffraction analysis (XRD) prove that the isolated AS is analogous to commercial starch. The cell culture scaffolds developed are superior to the existing monolayer culture. Infrared microscopy shows the AS-GG interaction and elucidates the mechanism of hydrogel formation. The physicochemical properties of the 3D-printed scaffold are analyzed to check the cell adhesion and growth; SEM images have confirmed that the AS-GG printed scaffold can support cell growth and proliferation, and the MTT assay shows good cell viability. Cell behavioral and migration studies reveal that cells are healthy. Since the scaffold is biocompatible, it can be 3D printed to any shape and structure and will biodegrade in the requisite time.

Polymer-Solvent Interactions in Modified Starches Pastes-Electrokinetic, Dynamic Light Scattering, Rheological and Low Field Nuclear Magnetic Resonance Approach

Starch paste is a very complex dispersion that cannot be clearly classified as a solution, colloid or suspension and many factors affects its properties. As these ambiguities constitute a barrier to technological development, the aim of this study was to investigate the interaction of starch macromolecules with water by analysing the results of rheological properties, low field nuclear magnetic resonance (LF NMR), dynamic light scattering (DLS) and ζ potential analyses. Starch pastes with a concentration of 1%, prepared with distilled water and buffered to pH values of 2.5, 7.0 and 9.5 were analysed. It was proved that the pH buffering substantially decreased the values of consistency index but the pH value itself was not significant. LF NMR studies indicated that the dissolution of starch in water resulted in a reduction in spin-lattice as well as spin-spin relaxation times. Moreover, changes in relaxation times followed the patterns observed in rheological studies. Electrokinetic and DLS analyses showed that potential values are primarily influenced by the properties of the starches themselves and, to a lesser extent, by the environmental conditions. The conducted research also showed complementarity and, to some extent, substitutability of the applied research methods as well as exclusion chromatography (a method not used in this work).

The Effect of Chemical Modification on the Rheological Properties and Structure of Food Grade Modified Starches

Starch in its pure form can be used as a functional component of numerous food products; however, much better results both in terms of technological and economical aspects are obtained with the use of modified starches. The aim of the work was to establish how chemical modification affects the molecular structure of potato starch and, as a consequence, its rheological properties as well as texture forming ability. Commercial food-grade potato starch preparations oxidized starch, acetylated starch, distarch phosphate, acetylated distarch phosphate and acetylated distarch adipate were the investigated material. The experimental methods included: viscographic analysis of pasting properties, flow rheometry, texture profile analysis, size exclusion chromatography with triple detection. The obtained data were further analyzed employing principal component and hierarchical cluster analysis. It was found that chemical modification leads to substantial changes in the molecular and functional properties of starch products. Oxidation process leads to depolymerization, which causes a substantial decrease in viscosity. Acetylation results mostly in stabilization of rheological properties during thermal processing. Crosslinking of starch leads to an improvement in thickening capabilities, while the type of crosslinking agent used for modification has a secondary effect. Sterilization of all types of modified potato starch pastes leads only to minor changes in their texture and rheological properties.