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ResumoObjetivou-se com este trabalho, caracterizar as farinhas de arroz (FA) e de batata-doce (FB), assim como suas propriedades reológicas. Primeiramente, determinou-se a composição proximal das farinhas realizando análises de umidade, atividade de água, acidez, pH, proteínas, lipídios, cinzas, fibra alimentar, carboidratos, teor de amilose, granulometria e cor; além das análises microbiológicas (Salmonela sp., Bacillus cereus, coliformes, bolores e leveduras). A propriedade de pasta do amido foi determinada para FA, FBD e suas mesclas. Na caracterização obtiveram-se os seguintes padrões: farinha de batata-doce (umidade 9,18%, proteína 9,92%, lipídios 1,72%, cinzas 1,51%, fibras alimentares 3,77% e carboidratos 77,81%) e farinha de arroz (umidade 13,31%, proteína 10,34%, lipídio 1,41%, cinzas 0,31%, fibras alimentares 0,76%, carboidratos 75,03%). As farinhas diferiram significativamente (p<0,05) em relação às coordenadas L*, a* e b* de cor, onde a farinha de batata-doce apresentou-se mais escura que a de arroz. Na avaliação das propriedades de pasta, observou-se que a temperatura de pasta de FA (88,65°C) foi superior em relação às demais amostras. A viscosidade máxima diminuiu com o aumento de FBD na mescla. Os valores de viscosidade final e de tendência à retrogradação diminuíram à medida que aumentou o teor de FBD na mescla. A mescla das farinhas permite sua utilização em produtos isentos de glúten para o público celíaco, aumentando as opções de consumo para os mesmos. AbstractThe objective of this work was to characterize rice flour (FA) and sweet potato (FB) flour, as well as its rheological properties. First, the proximal composition of the flours was determined by analyzing moisture, water activity, acidity, pH, proteins, lipids, ashes, dietary fiber, carbohydrates, amylose content, granulometry and color; besides the microbiological analyzes (Salmonela sp., Bacillus cereus, coliforms, molds and yeasts). The starch paste property was determined for FA, FBD and their mixtures. In the characterization the following standards were obtained: sweet potato flour (moisture 9.18%, protein 9.92%, lipids 1.72%, ash 1.51%, dietary fiber 3.77% and carbohydrates 77,81 %) and rice flour (13.31% moisture, 10.34% protein, 1.41% lipid, 0.31% ash, 0.76% dietary fiber, 75.03% carbohydrate). Flours differed significantly (p <0.05) in relation to L *, a * and b * color coordinates, where sweet potato flour was darker than rice. In the evaluation of the pulp properties, it was observed that the pulp temperature of FA (88,65 ° C) was higher in relation to the other samples. The maximum viscosity decreased with the increase of FBD in the blend. The final viscosity values and tendency to retrogradation decreased as the FBD content in the blend increased.The blend of flours allows its use in gluten-free products for the celiac public, increasing the consumption options for them.

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In this study functional properties of a galactose-rich heteropolysaccharide (GH) were accessed. The bands of a galactose-rich polysaccharide were found in FTIR spectra, including those from the fingerprint region. GH was characterized as a dark-red material (L* 25.86 ± 0.75, a* 9.46 ± 1.01, b* 0.65 ± 0.14, Chroma 9.48 ± 1.02) with antioxidant activity of 21.5 ± 0.08, 12.1 ± 0.06 and 0.46 ± 0.04 mmol Trolox Eq mg−1 GH in FRAP, DPPH and ABTS, respectively. GH presented 44.9% of esterification degree and 10.73 ± 0. 01 mg of GAE g−1. The production parameters of GH emulsions (GH concentration, time and ultrasound power) were optimized using a 23 Central Composite Rotatable Design (CCRD). Emulsion droplets presented particle size (d µm) varying from 0.823 ± 0.065 to 1.926 ± 0.151, polydispersity index (PDI) from 0.10 ± 0.05 to 0.40 ± 0.01 and zeta potential from −29.25 ± 3.98 to −33.75 ± 1.77. Finally, the high emulsifying activity (EA) (96.67%) and emulsion stability (ES) (97.44%) allow suggesting that GH is a promising polysaccharide for food applications.