Caracterização do amido nativo e modificação química do amido da fruta-de-lobo (Solanum lycocarpum) com tripolifosfato de sódio

Abstract

The aim of this study was to evaluate the effects of reaction time and concentration of sodium tripolyphosphate on phosphating, chemical and physical properties and functional properties by chemical modification (phosphorylation) of starch from the fruit-of-wolf. The starch in the fruit-of-native wolf was modified by varying the concentration of sodium tripolyphosphate and reaction times in order to establish limits on phosphorus suitable for use in foods, according to the Codex Alimentarius in the phosphate-modified starches are present residual phosphorus content of up to 0.4%.The results showed an increase of phosphorus content on getting the maximum under the law in time of 40 min with 7% sodium tripolyphosphate, the second-order mathematical model indicated that both studied factors influencing the phosphorylation of starch due the interaction of these independent variables. The starch was extracted from the wolf's fruit (Solanum lycocarpum) had a purity of 99.31% starch. Of physical and chemical properties of native starch and modified with concentrations of sodium tripolyphosphate and reaction time in the proportions of 5 / 20, 11/30 and 7 / 40, respectively, were determined the chemical composition, phosphorus content, starch content , amylose and the shape and size of starch granules. The experimental design was randomized and applied a multiple linear regression. Chemical modification of starch resulted in increased levels of phosphorus and ash, and decreased amounts of starch and amylose, achieving greater phosphorylation experimentally according to the law in time of 40 min to 7% of sodium tripolyphosphate. The functional properties were analyzed in samples with concentrations of sodium tripolyphosphate and reaction time in the proportions of 11/30 and 7/40, respectively. Native and modified starch were determined density, swelling power, solubility index, characterization of the gel, turbidity, syneresis, paste viscosity, calorimetric analysis. The starch fruit native wolf's had a density 1.86 g.mL-1 and the modification reduced the density of native starch. The swelling power and solubility index of native starch and modified significantly different from the temperature of 60 °C. The modification decreased the absorbance because it facilitates the passage of light. The syneresis was influenced by the change, an increase in the number of cycle storage, and a decrease in the chemical modification. The modified starches had higher paste viscosity than native starch because they have higher swelling power and solubility index in water. The calorimetric analysis of native starch and modified showed lower values in relation to dough temperatures obtained by RVA.