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ABSTRACT Eggs are one of nearly perfect protein foods, offering nutrients of great biological value. However, during storage, egg albumen and yolk components may alter and deteriorate egg quality. Therefore, the aim of this work was to assess egg quality during 9-week storage. Parameters such as Haugh unit, weight loss, egg width and length, specific gravity, yolk and albumen dimensions and their pH were evaluated weekly. A total of 270 eggs (n=5) collected from two different hen strains were evaluated under room (20 to 35 °C in summer; 11.2 to 29.7 °C in autumn) and refrigerated (0 to 5 °C in summer; -3.1 to 6.5 °C in autumn) temperatures. For storage time, an unfolding analysis was accomplished by regression analysis using orthogonal polynomials. As a second approach, principal component analysis (PCA) was performed in order to assess correlations among quality parameters on storage conditions and laying hen strains. By the end of the 9-week storage period, eggs kept under refrigeration presented similar quality parameters to eggs stored at room temperature for only 3 weeks. In contrast, eggs kept at room temperature presented faster degradation from week 1 to 5. No differences on egg quality parameters were noticed between white and brown shells eggs. PCA suggests that better egg quality (first week) was associated mainly with higher egg weight and its specific gravity, Haugh unit and albumen height. Eggs stored at room temperature should be consumed in 2 weeks or refrigerated until 8 weeks, preserving internal quality from farm to retail.

RESUMO Os ovos são um dos alimentos que oferecem nutrientes de grande valor biológico. Entretanto, no armazenamento, alguns componentes da clara e gema podem se alterar, deteriorando a qualidade dos ovos. Assim, este trabalho objetivou avaliar semanalmente parâmetros de qualidade como unidade Haugh, perda de peso, largura/comprimento do ovo, densidade específica, dimensões da clara/gema e pH durante 9 semanas de armazenamento. Foram coletados 270 ovos de duas linhagens de poedeiras e avaliados a temperatura ambiente (20 a 35 °C no verão; 11,2 a 29,7 °C no outono) e refrigerada (0 a 5 °C no verão; -3,1 a 6,5 ºC no outono). Para as condições de armazenamento, foi realizada uma análise de desdobramento por regressão por polinômios ortogonais. Ainda, análise de componentes principais (PCA), objetivou avaliar correlações entre parâmetros de qualidade em diferentes condições de armazenamento e linhagens de poedeira. Após 9 semanas de armazenamento, os ovos refrigerados apresentaram qualidade similar àqueles armazenados a temperatura ambiente por 3 semanas. Porém, sem refrigeração, os ovos apresentaram uma degradação mais rápida da semana 1 a 5. Não foram observadas diferenças nos parâmetros de qualidade dos ovos entre as diferentes colorações de casca (linhagens de poedeiras). PCA sugere que a melhor qualidade dos ovos (primeira semana) foi associada principalmente com valores elevados de peso e densidade específica do ovo, unidade Haugh e altura do albúmen. Ovos armazenados a temperatura ambiente devem ser consumidos até duas semanas ou mantidos sob refrigeração até 8 semanas, preservando a qualidade interna desde a granja até o armazenamento no varejo.

RESUMO

Dairy industry wastewater contains high levels of organic matter, consisting mainly of fat, protein and products of their partial microbial decomposition. In the present study, the use of continuous electrocoagulation is proposed for the primary treatment of dairy wastewater. The electrochemical treatment was carried out in a continuous flow cell with aluminum electrodes. The influence of the voltage, the distance between the electrodes and the hydraulic residence time (HRT) on the process performance was assessed, by measuring the removal of color, turbidity, total organic carbon (TOC) and chemical oxygen demand (COD). The optimum voltage, distance between the electrodes and HRT were 10 V, 1 cm and 90 min, respectively, yielding a current density of 13.3 A.m(-2). Under these conditions, removal of color, turbidity, TOC and COD were 94%, 93%, 65% and 69%, respectively, after a steady state was reached in the continuous flow reactor.

Assuntos

RESUMO

Anaerobic biodigestion is an appropriate alternative for the treatment of swine wastewater due to its biogas generation properties and the possibility of its application as a source of energy for heating or electricity. However, digestate can still contain high levels of turbidity, organic carbon and nutrients and must be correctly managed as a biofertilizer, or treated to avoid any impact on the environment. Considering this, electrocoagulation (EC) shows promise as a technology because of its ease of handling and high efficiency in effluent remediation. This study aimed to evaluate the performance of EC in a batch system in the treatment of swine wastewater digestate. The wastewater used in the treatment was sampled from a 10 m3 biodigestor effluent (digestate) located at Concórdia, Santa Catarina, Brazil. A batch-scale experiment was carried out to evaluate the following two variables: electrode distance (ED) and voltage applied (V). The removal efficiency levels (%) for the best operational condition (2 cm, 5 V) after 30 min were: 97 %, 98 %, 77 % and 10 % for color, turbidity, total organic carbon (TOC) and total nitrogen (TN), respectively. The EC batch system produced efficient results, underlining its promise as an alternative to be applied in the treatment of digestate.(AU)

Assuntos

RESUMO

Anaerobic biodigestion is an appropriate alternative for the treatment of swine wastewater due to its biogas generation properties and the possibility of its application as a source of energy for heating or electricity. However, digestate can still contain high levels of turbidity, organic carbon and nutrients and must be correctly managed as a biofertilizer, or treated to avoid any impact on the environment. Considering this, electrocoagulation (EC) shows promise as a technology because of its ease of handling and high efficiency in effluent remediation. This study aimed to evaluate the performance of EC in a batch system in the treatment of swine wastewater digestate. The wastewater used in the treatment was sampled from a 10 m3 biodigestor effluent (digestate) located at Concórdia, Santa Catarina, Brazil. A batch-scale experiment was carried out to evaluate the following two variables: electrode distance (ED) and voltage applied (V). The removal efficiency levels (%) for the best operational condition (2 cm, 5 V) after 30 min were: 97 %, 98 %, 77 % and 10 % for color, turbidity, total organic carbon (TOC) and total nitrogen (TN), respectively. The EC batch system produced efficient results, underlining its promise as an alternative to be applied in the treatment of digestate.

Assuntos