Níveis de deoxinivalenol, compostos fenólicos e atividade antioxidante de farinha de trigo após processo de polimento

The objective of this work was to evaluate the effect of the debranning process on the deoxynivalenol (DON) content, phenolic compounds, and antioxidant activity of wheat flours, in order to determine which milling technology provides the safest and most nutritional wheat products. Grain samples from the BRS Marcante, BRS Reponte, and BRS 374 wheat (Triticum aestivum) cultivars were used to obtain both whole-wheat and white flours. For whole-wheat, grains were debranned at different times (20 and 40 s). The debranning process significantly reduced the DON content in the whole-wheat flours from all cultivars. The DON concentration decreased 22 and 28% in the 20 and 40 s debranning treatments, respectively, when compared with the treatment without debranning. In addition, phenolic compound content and antioxidant capacity are significantly higher in the whole-wheat flours. The debranning process contributes to the production of safer and healthier foods, by reducing DON content and retaining phenolic compounds and antioxidant activity in whole-wheat flours.O objetivo deste trabalho foi avaliar o efeito do processo de polimento nos níveis de deoxinivalenol (DON), nos compostos fenólicos e na atividade antioxidante de farinhas de trigo, para determinar a tecnologia de moagem que fornece os produtos de trigo mais seguros e nutritivos. Amostras de grãos das cultivares de trigo (Triticum aestivum) BRS Marcante, BRS Reponte e BRS 374 foram utilizadas para obter farinhas de trigo integral e branca. Para a farinha integral, os grãos foram submetidos a diferentes períodos (20 e 40 s) de polimento. O processo de polimento reduziu significativamente o teor de DON nas farinhas de trigo integral de todas as cultivares. A concentração de DON diminuiu 22 e 28% nos tratamentos polimento por 20 e 40 s, respectivamente, quando comparada à do tratamento sem polimento. Além disso, os níveis de compostos fenólicos e a capacidade antioxidante são significativamente maiores nas farinhas de trigo integral. O processo de polimento contribui para a produção de alimentos mais seguros e saudáveis, ao reduzir o teor de DON e conservar os compostos fenólicos e a atividade antioxidante na farinha de trigo integral

Oxidation of potato starch with different sodium hypochlorite concentrations and its effect on biodegradable films

AbstractThe objective of this study was to evaluate the effects of oxidation with sodium hypochlorite at different concentrations of active chlorine (0.5, 1.0 and 1.5 g/100 g) on the physicochemical, morphological, pasting, thermal and gel texture properties of potato starch. The native and oxidized starches were used in different concentrations (3.0, 4.0 and 5.0 g starch/100 mL) for the preparation of biodegradable films using glycerol as plasticizer. The films were evaluated for their mechanical properties, color, water solubility and permeability of water vapor. The degree of oxidation potato starches was more intense as there was an increased concentration of active chlorine in the reaction. Films made with oxidized starch with the highest level of active chlorine had lower tensile strength when compared to native starch films. Also, these films had a lower water solubility and water vapor permeability as compared to the native starch films

Structural, morphological, and physicochemical properties of acetylated high-, medium-, and low-amylose rice starches

AbstractThe high-, medium-, and low-amylose rice starches were isolated by the alkaline method and acetylated by using acetic anhydride for 10, 30, and 90min of reaction. The degree of substitution (DS), the Fourier-transformed infrared spectroscopy (FTIR), the X-ray diffractograms, the thermal, morphological, and pasting properties, and the swelling power and solubility of native and acetylated starches were evaluated. The DS of the low-amylose rice starch was higher than the DS of the medium- and the high-amylose rice starches. The introduction of acetyl groups was confirmed by FTIR spectroscopy. The acetylation treatment reduced the crystallinity, the viscosity, the swelling power, and the solubility of rice starch; however, there was an increase in the thermal stability of rice starch modified by acetylation

Efeito de oxidantes, de acidos organicos e da fração soluvel em agua na propriedade de expansão do amido de mandioca fermentado

Orientador: Cesar Francisco CiaccoTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de AlimentosResumo: Pesquisas recentes sobre o desenvolvimento da propriedade de expansão do amido de mandioca fermentado e seco ao sol durante o fomeamento indicaram ser a oxidação do amido, promovida pela radiação UV proveniente da luz solar, na presença de ácidos orgânicos, um dos fatores responsáveis por este fenômeno. O presente trabalho estudou o efeito de oxidantes na propriedade de expansão do amido de mandioca fermentado seco artificialmente, assim como, o papel de sua fração solúvel em água e dos ácidos orgânicos ¿Observação: O resumo, na íntegra poderá ser visualizado no texto completo da tese digital.Abstract: Oxidation promoted by UV radiation during the sun drying of sour cassava starch in the presence of organic acids, has been indicated as being responsible for its expansion during baking ...Note: The complete abstract is available with the full electronic digital thesis or dissertations.DoutoradoDoutor em Tecnologia de Alimento

Umidade de colheita, métodos de secagem e tempo de armazenamento na qualidade tecnológica de grãos de trigo (cv. 'Embrapa 16') Harvest moisture, drying methods and storage period on the technological quality of wheat grains (cv. 'Embrapa 16')

O objetivo deste trabalho foi estudar os sistemas umidades de colheita e métodos de secagem em função do período de armazenamento sobre a conservabilidade e qualidade tecnológica de trigo. Grãos de trigo (Triticum aestivum L), cultivar 'Embrapa 16', produzidos na Granja Bretanhas, município de Jaguarão, Rio Grande do Sul (RS), safra agrícola de 1997/1998, foram colhidos secos naturalmente nas próprias plantas (14% de umidade), com 16 e 18% de umidade. As amostras colhidas com umidade de 16 e 18% foram submetidas à secagem artificial pelo método intermitente, com ar a 70°C; estacionário, com ar a 45°C; e estacionário, com ar sem aquecimento. Os grãos secos foram armazenados em sistema convencional, pelo período de 12 meses, com a realização de avaliações a cada quadrimestre. O trigo colhido seco na planta apresentou qualidade tecnológica inferior e menor conservabilidade ao armazenamento em comparação com o trigo colhido com umidade superior a 14% e seco em secador artificial.The objective of this research was to study the harvest moisture and drying method systems as a function to storage period on the conservability and technological quality of wheat. Grains of wheat (Triticum aestivum L), cultivar 'Embrapa 16', produced in the Granja Bretanhas, in Jaguarão, RS, agricultural harvest of 1997/1998 were harvested dry in the plant (14% of moisture), with 16 and 18% of moisture. The samples harvested with moisture of 16 and 18% were submitted to artificial drying by intermittent method, with air at 70°C, stationary, with air at 45°C; and stationary, at room temperature. The grains were stored in a conventional system, during 12 months, with the realization of evaluations at 4 month intervals. Wheat grains harvested dry shown inferior technological quality and conservability in storage as compared to harvested with moisture above 14% and dry at artificial dryer

Morphological evaluation and antioxidant activity of ultrafine zein fibers and grape pomace extract produced by electrospinning

Neste estudo avaliou fibras ultrafinas de zeína produzidas por electrospinning para a encapsulação de extrato de bagaço de uva. O bagaço de uva é uma fonte rica em compostos bioativos, incluindo antioxidantes. O processo de electrospinning resultou em fibras ultrafinas com morfologia contínua e diâmetros médios levemente reduzidos após a incorporação do extrato de bagaço de uva. As fibras com 10% de extrato mantiveram a capacidade de eliminar o radical livre ABTS, indicando seu potencial como agente antioxidante na conservação de alimentos. Essas fibras podem ser uma alternativa para proteger e estabilizar os compostos bioativos do bagaço de uva

Acetylation of barnyardgrass starch with acetic anhydride under iodine catalysis

AbstractBarnyardgrass (Echinochloa crus-galli) is an invasive plant that is difficult to control and is found in abundance as part of the waste of the paddy industry. In this study, barnyardgrass starch was extracted and studied to obtain a novel starch with potential food and non-food applications. We report some of the physicochemical, functional and morphological properties as well as the effect of modifying this starch with acetic anhydride by catalysis with 1, 5 or 10mM of iodine. The extent of the introduction of acetyl groups increased with increasing iodine levels as catalyst. The shape of the granules remained unaltered, but there were low levels of surface corrosion and the overall relative crystallinity decreased. The pasting temperature, enthalpy and other gelatinisation temperatures were reduced by the modification. There was an increase in the viscosity of the pastes, except for the peak viscosity, which was strongly reduced in 10mM iodine