Produção caracterização e propriedades de pasta de amido fosfatado obtido por extensão

AUTOR(ES)
DATA DE PUBLICAÇÃO

1985

RESUMO

Corn starch phosphate was produced from corn starch in the extrusor Brabender type 20 D-N at different temperatures of extrusion, sodium tripolyphosphate concentration (STP) and pH. These products were characterized by determination of: degree of substitution (DS), water absorption index (WAI), water solubility index (WSI), paste clarity and retrogradation tests. The paste properties and the effects of the ingredients and starch concentrations on these properties were verified for the starch phosphate with a DS of 0.0022 produced at 130°C with 1.4 g of TPS/100 mL of water and pH 5.5. Some of the above determinations were also carried out on the original corn starch, a corn starch phosphate obtained by the conventional process and on extruded corn starch without TPS. The DS values did not present marked differences in the products extruded at 130, 145, 160 and 175°C (DS between 0.0030 and 0.0022), but rose in that extruded at 200°C (DS of 0.0053). The WAI values did not show significant variation with the different extrusion temperatures, while the WSI reached a maximum at 175°C. Marked differences were not observed in the paste clarity of the products extruded at 130, 145, 160 e 175°C. The clearest paste was obtained at an extrusion temperature of 200°C. The starch phosphate pastes obtained in this assay showed little or no tendency to retrograde during seventeen days of storage. It was observed that the main influence of the DS was on the paste clarity and the retrogradation tendency. On the other hand, the WAI and WSI values were affected by the extrusion process, independently of the presence of STP. In the study of the effect of STP concentration on starch phosphate characteristics, it was verified that increases in the STP concentration up to 1.4 g/100 mL of water were followed by increases in the DS. Above this concentration changes were not observed in the DS (0.0035} of the extruded starch at l30°C. The WAI and WSI values were constant, while the paste clarity and the tendency to retrograde were influenced by the DS of the product. Phosphate starch produced at pH 8.5 presented a greater DS (0.0035) than that produced at pH 5.5 (DS of 0.0022). Giving similar results to those obtained by varying the STP concentration, the phosphate starches produced at different pH values showed no significant variations in their WSI and WAI values, although the paste clarity and retrogradation tendencies were influenced by the DS of the products. When comparing the properties of others starches, with those of the phosphate starch pastes obtained by extrusion (DS of 0.0022) and used at different sample concentrations, pH values and sodium chloride and sucrose concentrations, it was showm that the introduction of phosphate groups did not significantly change these properties, which were, however, influenced by the extrusion process. The maximum paste viscosity of this starch was mainly altered by the starch concentration in the suspension and the presence of sucrose. Different pH values and sodium chloride concentrations did not significantly change the viscoamylographic properties of this product

ASSUNTO(S)

massas alimenticias amido fosfatos

ACESSO AO ARTIGO

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