Physicochemical Properties and Digestion Resistance of Acetylated Starch Obtained from Annealed Starch

One of the examples of physical starch modifications is the retention of a starch suspension in water having a temperature slightly lower than the pasting temperature (annealing). The aim of this study was to investigate the effect of the annealing process performed at various temperatures as the first stage of starch modification. The annealed starch preparations were then esterified using acetic acid anhydride. Finally, the annealed and acetylated starch preparations were determined for their properties. The annealing of starch before acetylation triggered changes in the properties of the modified preparations. It contributed to a higher degree of starch substitution with acetic acid residues and to the increased swelling power of starch. Both these properties were also affected by the annealing temperature. The highest resistance to amylolysis was found in the case of the starch preparation annealed at 53.5 °C and acetylated. The double modification involving annealing and acetylation processes increased the onset and end pasting temperatures compared to the acetylation alone. Similar observations were made for the consistency coefficient and yield point.

Investigation of the influence of double modification of starch as of natural polymer, on rheological characteristics of compositions and their film-producting properties

Starch is a natural polymer that has unique properties, which consist of the annual renewal of raw materials and the ability to create biodegradable materials based on starch. Modification of starch leads to changes in its chemical structure, which is associated with both the method of modification and the introduction of active chemicals into its structure. Double modification occurs due to the simultaneous use of physical or mechanical method with the addition of the necessary chemicals. Physical methods of starch modification include microwave and ultrasonic irradiation. The aim of the work was to study the physicochemical properties of corn starch after double modification and its use in the creation of film-forming samples. The urgency of this work is due to the need that in order to protect the environment the basis of technological compositions used in industry should be natural polymers, this will minimize the negative impact on the environment and develop environmentally friendly compositions and functional systems for various purposes. The structure of two types of corn starch was studied by pyrolytic mass spectrometry and their characteristic mass spectra were determined. The influence of physical modification by ultrasonic and microwave irradiation of corn starch using plasticizing additives based on modified soybean and rapeseed oils on the rheological properties of the compositions, solubility and swelling was studied. It was found that the modification of starch using ultrasonic irradiation leads to a significant decrease in dynamic viscosity, while after microwave irradiation the viscosity increases. Double-modified corn starch was investigated for the formation of film-forming materials with the addition of NaКMC and polyvinyl alcohol. The strength characteristics of the films of the compositions are determined.

Double Modification of Polyether Ionophores: Synthesis and Biological Activity of Novel Salinomycin Derivatives

Polyether ionophore antibiotics represent a large group of more than 120 lipid-solublecompounds that are widely used in veterinary medicine because of their significant antimicrobialactivity [...]

Double Modification Of AlSi9Mg Alloy With Boron, Titanium And Strontium

The microstructure of an unmodified AlSi9Mg alloy comprises large primary α phase dendrites, eutectic β phase crystals and eutectic α phase. This composition is responsible for the alloy’s low strength parameters, and it limits the extent of practical applications. The mechanical properties of hypoeutectic silumins can be improved through chemical modification as well as traditional or technological processing. Modification improves the mechanical properties of alloys through grain refinement. This study presents the results of double modification of an AlSi9Mg alloy with strontium, boron and titanium. The influence of the analyzed modifiers on the microstructure and mechanical properties of the processed alloy was presented in graphs. The modification of a hypoeutectic AlSi9Mg alloy improved the alloy’s properties. The results of the tests indicate that the mechanical properties of the modified alloy are determined by the sequence in which the components are introduced to the alloy.