Application of Films Based on Chitosan and Xanthan Gum in Refrigerated Fish Conservation

Abstract This research aims to determine the efficiency of chitosan and xanthan gum films in conservation of croaker fillets kept in refrigeration for 9 days. Proximal composition, loss of mass, color, pH, TVB-N (Total Volatile Bases) and microbiological profile were assessed. The films were prepared with chitosan and xanthan gum in varying mass proportions 100:0, m:m (C100XG0); 60:40, m:m (C60XG40); 50:50, m:m (C50XG50). They presented the respective values for moisture content, water solubility, thickness and water vapor permeability: 24.59%, 19.50%, 0.086 mm and 11.45gm-1.s-1.Pa-1for C100XG0; 24.58%; 20.27%, 0.091 mm and 10.41 gm-1.s-1.Pa-1for C60XG40; 22.11%, 22.06%, 0.089 mm and 10.68 gm-1.s-1.Pa-1 forC50XG50.The films were made in small bags format capable to hold about 20 g of fish fillets. A control sample was prepared in parallel, using polyethylene bags under the same storage conditions. The results showed that the chitosan films combined with xanthan gum had excellent antimicrobial properties, capable of preserving the quality of chilled fish fillets during the studied period, since it inhibited the growth of Staphylococcus coagulase-positive, Salmonella spp and coliforms at 45 ° C. Mass loss of the croaker fillets was not significantly affected by xanthan gum addition to the films. On the other hand, xanthan gum addition affected pH and color parameters of the corvina fillets. It was also verified that the combination of these two polymers promoted the reduction of N-BVT, being the C50XG50 film that presented the best response.

Lipid profiles of rats fed with diets supplemented with vitamins niacin and pyridoxine

Hypercholesterolemia is a major risk factor for cardiovascular disease. Supplements containing the vitamins niacin (B3) and pyridoxine (B6) can promote the reduction of total cholesterol and an increase in HDL cholesterol. In this study, the effects of diets supplemented with niacin (B3) and pyridoxine (B6) on the hepatic and serum lipid profiles of Wistar rats were assessed. The diets were prepared with combinations of three concentrations of niacin (3, 4 and 5 g/kg) and pyridoxine (6, 12 and 18 mg/kg) and one with neither vitamin. The animals were divided into eleven experimental groups of six animals per group, and nine groups were fed on a standard diet with 7.5% fat and vitamin supplementation. Another group was fed with 7.5% fat without vitamin supplements. A control group received the standard diet (AIN-93M) without modifications (4% fat). The weight gain, food intake, serum and hepatic total cholesterol, serum cholesterol fractions (HDL, LDL, and VLDL), serum and hepatic triacylglycerols and hepatic and fecal lipid contents were measured after 30 days. The diet with the highest concentration of niacin and lowest concentration of pyridoxine had the lowest level of total hepatic cholesterol. Hepatic triacylglycerols were reduced by the highest concentration of niacin (5 g/kg), and this reduction was enhanced by increasing the pyridoxine concentration. The diets supplemented with niacin and pyridoxine reduced the levels of serum total cholesterol, LDL, VLDL, triacylglycerols and hepatic lipids. These effects on the lipid profile varied with the concentrations of the two vitamins and the interactions between them.

Efeitos de processo de secagem e tempo de armazenamento na qualidade tecnológica de trigo / Effects of drying process and storage time on technological quality of wheat

Neste trabalho, objetivou-se estudar a influência dos processos de secagem estacionário e intermitente e do tempo de armazenamento na qualidade tecnológica de grãos de trigo, cultivar Embrapa 16 colhidos com teor de água de 15 por cento e 19 por cento. Grãos de trigo (Triticum aestivum L) foram produzidos em lavoura comercial da Granja Bretanhas, Cooperativa Arrozeira Extremo Sul, no município de Jaguarão, RS. O experimento foi conduzido em delineamento inteiramente casualizado, utilizando dois teores de água de colheita (15 por cento e 19 por cento), dois processos de secagem (estacionário e intermitente) e quatro tempos de armazenamento. A secagem foi realizada até o teor de água de 13 por cento e os grãos acondicionados em embalagens de algodão, em sistema de armazenamento convencional pelo período de 12 meses. Nos tempos zero, 4, 8 e 12 meses foram realizadas as análises de teor de água, peso hectolitro, cinzas, lipídios, acidez graxa, número de queda e alveografia. Os parâmetros mais efetivos para avaliar o efeito dos processos de secagem de trigo intermitente e estacionário em função do tempo de armazenamento foram peso do hectolitro, lipídios e acidez graxa indicando melhor qualidade tecnológica na secagem realizada em secador intermitente. O trigo, cultivar Embrapa 16, colhido seco na planta apresentou qualidade tecnológica inferior e menor conservabilidade ao armazenamento do que o colhido de forma antecipada e seco em secador intermitente.

The objective of this work was to investigate the influence of stationary and intermittent drying process was well as storage time on the technological quality of wheat, cultivar Embrapa 16 harvested at 15 percent and 19 percent moisture content. Wheat grains (Triticum aestivum L) were produced in a commercial plantation at Granja Bretanhas, Cooperativa Arrozeira Extremo Sul, in Jaguarão, RS. The experiment was carried out in a completely randomized design, using two harvest moisture contents (15 percent and 19 percent), two drying processes (stationary and intermittent) and 4 storage times. Drying was performed up to 13 percent moisture content and the grains were kept in cotton packets, at conventional storage system for 12 months. Moisture content, hectoliter weight, ash, fat, fatty acid, falling number and alveography were evaluated at zero, 4, 8 and 12 months. The results of hectoliter weight, fat, fatty acid, ash and falling number showed effective when evaluated the technological quality of wheat, cultivar Embrapa 16 harvested at 15 percent and 19 percent moisture content. Wheat harvest dry at the plant shows inferior technological quality and less conservability in storage as compared to pre-harvested wheat dried at intermittent dryer.

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 por cento de umidade), com 16 e 18 por cento de umidade. As amostras colhidas com umidade de 16 e 18 por cento 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 por cento 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 percent of moisture), with 16 and 18 percent of moisture. The samples harvested with moisture of 16 and 18 percent 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 percent and dry at artificial dryer.