The transport of water in four EVOH copolymers commonly used in high barrier food packages was characterized through permeation (continuous flow) and gravimetric experiments at different rela tive humidities and 23 ± 2°C. Water sorption isotherms were fitted with the D'Arcy and Watts' equa tion. From these data, the value of the solubility coefficient (S, as defined by Henry's law) was deter mined and was found constant within a 0.2-0.75 water activity (a w) range. Water uptake at the same a w increased as the EVOH ethylene content decreased. The permeability coefficient (P) for water through EVOH was determined as a function of water activity. The permeability was constant within the range of 0.3-0.75 a w and decreased with EVOH ethylene content. At high relative humidities (a w > 0.75) the value of permeability increased by up to two orders of magnitude. In this range, the higher the ethylene content the lesser the value of P.

El conocimiento de las interacciones del agua en el cafe en sus diferentes formas, verde, tosdado y soluble, y de las relaciones humedad-actividad del agua (aw) de estos productos, es necesario por diferentes razones, en las que se encuentran: 1) determinar la aw y la estabilidad durante el almacenamiento de productos, 2) monitorizar y establecer las condiciones del proceso de secado del extracto de cafe, 3) controlar el contenido en humedad de estos productos que estan sometidos a controles legislativos nacionales e internacionales.

This work studies the influence of the roasting process on sorption isotherms of almond, hazelnut and peanut over the normal range of storage temperatures (5, 25 and 45 °C) The results obtained showed that water sorption properties of unroasted nuts are affected by fat content. The mono layer moisture content and water affinity (sorption heat, Qₛ) increased when the nut fat content decreased. After roasting, a more homogeneous water affinity was observed for the different products, although fat content still affected the monolayer capacity. Also, roasting reduced mono layer moisture content and Qₛ values in each sample and made the moisturizing process less spontaneous (decreasing the thermodynamic driving force). These results are consistent with an increase of the hydrophobicity of the cellular components of nuts due to the enhancement of lipid interactions. The water binding properties of active points in the roasted products were reduced and, hence, some water sorption active points disappeared.

PORTUGUES: Procurou-se estudar a absorcao de agua em funcao da capacidade da semente (efeito dependente da cultivar) utilizando variedades semeadas nas mesmas condicoes. Antes da fase de embebicao das sementes em agua, estas possuiam igual grau de humidade. Nao se encontraram correlacoes entre as cultivares e os cultigrupos utilizados. No entanto sao notorias as diferencas da absorcao da agua entre as varias cultivares, sendo independente do tamanho da semente. Sabido que este factor tem um coeficiente de hereditabilidade elevado, pode facilmente vir a ser utilizado como um dos padroes de seleccao.

The effects of swine wastewater on atrazine dissipation and formation of bound residues in subtropical clay soil were investigated in this study. The experiment was carried out in laboratory, under room conditions, where samples of Rhodic Hapludox soil received 168.61 mg kg-1 of atrazine and were incubated for 60 days in the following treatments: T1 (sterilized soil + swine wastewater), T2 (sterilized soil + distilled water), T3 (Non sterilized soil + swine wastewater) and T4 (Non sterilized soil + distilled water). The extractable residues and bound residues of atrazine were extracted and analyzed by high performance liquid chromatography. The results showed no effect of swine wastewater on atrazine dissipation. However, the addition of swine wastewater favored the increase of bound residues, which can increase the persistence of atrazine in the environment and reduce its bioavailability.<br>Os efeitos da aplicação de água residuária da suinocultura (ARS) na dissipação de atrazina e formação de resíduos ligados em solo subtropical argiloso foram investigados neste trabalho. O experimento foi conduzido em laboratório, sob condições controladas, onde amostras de Latossolo Vermelho distroférrico receberam a aplicação de 168,61 mg kg-1 de atrazina e foram incubadas durante 60 dias, de acordo com os seguintes tratamentos: T1 (Solo esterilizado + ARS); T2 (Solo esterilizado + água destilada); T3 (Solo não esterilizado + ARS), e T4 (Solo não esterilizado + água destilada). Os resíduos extraíveis de atrazina e resíduos ligados foram extraídos e analisados por cromatografía líquida de alta eficiência. Os resultados mostraram que não houve efeito da aplicação de ARS na dissipação de atrazina. Entretanto, a adição de ARS ao solo favoreceu o aumento da formação de resíduos ligados, o que pode aumentar a persistência da atrazina no ambiente e diminuir sua biodisponibilidade.

Managed aquifer recharge (MAR) refers to intentional infiltration of surface water to an aquifer for facilitating natural water treatment and storage. MAR is often used as a treatment to remove natural organic matter from water in drinking water production. The sustainability of MAR depends on how the aquifer capacity to remove organic matter will evolve over the long term. This report explores the behavior of MAR systems by using a natural lake–aquifer system as a surrogate. Natural infiltration of lake water to groundwater has been going on for millennia at the research site in Finland chosen for this study. According to the measurements, the mean concentration of total organic carbon (TOC) in lake water was 3.0 mg/L. Within the distance of 3 m from the lake bank (retention time 7–15 days), already 46% of TOC was removed. At greater distances along the flow paths within the aquifer, 80–90% of TOC was removed. The observed TOC removal in the aquifer was slightly higher than the reported values at MAR sites, indicating that MAR can be an effective solution to the problem of removing natural organic matter in the long term. Signs of accumulation of organic matter were not observed in the aquifer, which suggests that biodegradation was the main removal method, and the role of sorption was minor. Several processes had an impact on oxygen levels in the aquifer, which led to spatial and seasonal changes in the redox conditions and in the iron and manganese concentrations in groundwater.