6 research outputs found

    Modelling of dried apple rehydration indices using ANN

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    The purpose of the research was to study the effect of different drying and rehydration conditions on the rehydration indices of apple and to model the rehydration indices of apple using artificial neural networks. The research involved the examination of the rehydration process of 10 mm apple cubes, which were dried in natural convection (drying air velocity), forced convection and fluidization at the following drying temperatures 50, 60 and 70°C. The process of rehydration was conducted in distilled water at the following temperatures 20, 45, 70 and 95°C. Five rehydration indices were used to express rehydration. Artificial neural networks (MLP 3-5-1 and MLP 3-4-1) were used to make the rehydration indices dependent on both drying and rehydration parameters: drying temperatures, v and following temperatures. Five statistical tools, i.e. correlation coefficient, mean bias error, root mean square error, reduced chi-square, and t-statistic method (t-stat), were applied to determine the fit. To identify critical parameters and their impact on the ANN outputs, a sensitivity analysis (backward stepwise method) was performed

    Association between incidence of Lyme disease and spring-early summer season temperature changes in Hungary - 1998-2010

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    The increase of Lyme borreliosis (LB) can be expected due to climate change, while the distribution of the disease and annual activity of the vector and host animals depend on several factors of the environment. The presented study aimed to assess expressly the spring season temperature dependence on the incidence of LB in Hungary. The weekly LB data were obtained from the National Epidemiologic and Surveillance System for a period of 13 years – 1998–2010. Daily temperature data were derived from the European Climate Assessment and Dataset. The association was studied at national level, descriptive statistics and linear regression models were applied. A significant increasing trend was observed in the mean temperature of the analysed years (0.052 °C per year). The annual LB incidence doubled during the 13 year period. The incidence rates of the periods 1998–2001 and 2007–2010 were 11.1 resp. 17.0 per 100,000. The start of a steep increase in weekly LB incidence (0.1 per 100,000) shifted significantly by 3 weeks earlier, the start date of spring showed similar trend (p=0.0041). LB incidence increased more steadily in spring than in summer, with 79% of the increase being reported during weeks 15–28, with maximum rates of increase occurring in weeks 23–25. The trend was significant between the weeks 15–28. In the warmer years with 19.02 °C mean temperature in May and June, the LB incidence curve reached the annual peak 2–3 weeks earlier, and the descending phase of the curve started earlier than in the colder years with 17.06 °C of the same period

    The effect of drying and long-term storage on colour and carotenoids content of giant pumpkin (Cucurbita maxima)

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    The objective of this study was to characterise the quality of giant pumpkin dried in different conditions as well as to determine the best combination(s) of drying conditions, based on colour and chemical composition of dried material. Samples of three pumpkin cultivars (Amazonka, Justynka- 957 and Ambar) were dried at five different temperatures (40°C, 50°C, 60°C, 70°C, 80°C) using three different drying methods (forced convection in tunnel dryer, natural convection in chamber dryer and hybrid drying which combined a tunnel drying and fluidized-bed drying). It has been shown that variability of samples resulted primarily from the redness, yellowness, lutein and β-carotene. Samples were scored based on the range of responses identified by factor analysis in order to find an optimal combination of cultivar, temperature and drying method. The three subsequent highest scores were obtained for samples of Ambar cultivar, dried using hybrid drying at 40, 60 and 80°C respectively
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