| Abstract [eng] |
The most common natural polymer in the world - starch is used not only in food and cosmetics, but also in paper, adhesives, textiles, chemicals, bioplastics and biofuels production. However, the production of starch containing products, often encounter difficulties due to natural starch: in low shear resistance, temperature extremes, resistance to acidity. Also wheat starch contains non-starch materials such as lipids, proteins who initiates starch retrogradation process, which could affect product quality. Therefore, to improve and optimize properties of the starch, it is being modified. Aim of the study was to find the best way to modify natural wheat starch and determine its rheological properties. Different reagent ratios of starch modification, and changing the temperature of the reaction mixture has been produced in obtaining phosphorylated starch with good properties. It was determined how much elemental phosphorus has reacted with starch, calculated reaction efficiency, determined how much of di-starch monophosphate and mono starch monophosphate anion moles are in 1 g of starch by potentiometric titration. The phosphorylation kinetics showed that the optimum reaction time is 4 hours, rheological studies have showed that the best features of the starch which has been produced in a molar ratio of reagent was: [St]: [NaOH]: [STMP]: [H2O] = [1]: [8]: [0,5]: [10] T = 45 °C. Made starch glue from the finest phosphorylated starch which contained best properties and then measured maximum gelatinization viscosity which was 2,5 times higher than native starch glue and cooled gel (at 25 oC) viscosity was 2,4 times higher. Also measured difference from industrial starch (MYLD BOND) – maximum gelatinization viscosity was 1,5 times smaller, and gel viscosity was 1,4 times smaller compared to phosphorylated starch with best rheological properties. Also found that removed non-starch materials effect gel viscosity – G’ modulus is slightly smaller. |
