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João Renato de Jesus Junqueira Jefferson Luiz Gomes Corrêa Kamilla Soares de Mendonça Ronaldo Elias de Mello Júnior Amanda Umbelina de Souza 《Food and Bioprocess Technology》2018,11(10):1863-1875
Pulsed vacuum osmotic dehydration (PVOD) is a widely used technique for reducing moisture content and water activity in biological products. This study aimed to analyze the effect of vacuum application (VA) on PVOD of beetroot, carrot, and eggplant slices, with respect to chemical (moisture, water activity, specific pigments, polyphenols, and sodium content), optical (color), mechanical (shrinkage, maximum stress, and elasticity), and structural (microstructure) properties. PVOD was conducted at three different vacuum pressures (0, 40, and 80 kPa, for 10 min), during a total process time of 300 min. Osmotic processing was performed at 35 °C by using a ternary osmotic solution [40% sucrose +?10% sodium chloride (w/w)]. Eggplant and carrot samples were more sensitive to VA, compared to beetroot. This was related to their porous and less compact structure. In general, VA reduced the moisture content and water activity and preserved the carotenoid content. VA caused loss of betalain and phenolic acid, favored sodium uptake, and induced significant changes in the optical, mechanical, and structural properties, compared to the osmotic processing conducted at atmospheric pressure. 相似文献
134.
Jesus Alvarez Jose Alvarez-Ramirez Gerardo Espinosa-Perez Alexander Schaum 《Chemical engineering science》2011,(23):6280
Traditionally, stabilization of chemical reacting systems has been achieved with linear P or PD compensation schemes. Practical and numerical results have showed that classical linear compensation can yield acceptable performance. On the other hand, recent years have witnessed the emergence of systematic feedback control strategies based on energy and port-interconnected systems. These approaches exploit the physical structure of the chemical reactor to construct compensation schemes with physical appealing. The aim of this work is to show that traditional PD compensation for CSTRs can be interpreted in terms of mechanical system analogies. In the line of energy shaping plus damping injection for robotic systems, it is shown that proportional feedback is a type of potential energy shaping to accommodate a unique equilibrium point. On the other hand, derivative control acts as a damping injector for the energy balance within the chemical reactor. The stability proof uses a novel approach to convert the temperature dynamics into a second-order systems where the mechanical analogies become more evident. In this way, the stability analysis can be performed with singular perturbation methods with a Lyapunov function for the energy balance derived from a “potential plus kinetics” energy construction. 相似文献
135.
Oliveira TW Leandro CG de Jesus Deiró TC dos Santos Perez G da França Silva D Druzian JI Couto RD Barreto-Medeiros JM 《Lipids》2011,46(11):1071-1074
The main goal of the present study was to evaluate the long-term effects of a perinatal palatable high-fat diet on the food
intake and cholesterol profile of adult rats. Male Wistar rats (aged 22 days) were divided into two groups according to their
mother’s diet during gestation and lactation (C
p, n = 10; pups from control mothers; and HLp
n = 10; pups from mothers fed a palatable high-fat diet). At the 76th day, pups were housed individually for 14 days, and daily
food consumption was determined during a period of 6 days. Blood from 100-day-old rats was sampled by cardiac puncture. Fasting
(12 h) serum glucose, total cholesterol, LDL-C, HDL-C, triglycerides (TG), and VLDL-C levels were determined. The measurement
of food intake was higher in the animals submitted to a hyperlipidic diet during the perinatal period. Serum total cholesterol,
LDL-C, HDL-C, TG, VLDL-C and glycemia were increased in the HLp group compared to the control group. Our findings show that an early life environment with a high-fat diet can contribute
to metabolic disease in later life. 相似文献
136.
Marina O.S. Dias Tassia L. Junqueira Otávio Cavalett Marcelo P. Cunha Charles D.F. Jesus Paulo E. Mantelatto Carlos E.V. Rossell Rubens Maciel Filho Antonio Bonomi 《Chemical Engineering Research and Design》2013
Sugarcane bagasse and trash are used as fuels in cogeneration systems for bioethanol production, supplying steam and electricity, but may also be used as feedstock for second generation ethanol. The amount of surplus lignocellulosic material used as feedstock depends on the energy consumption of the production process; residues of the pretreatment and hydrolysis operations (residual cellulose, lignin and eventually biogas from pentoses biodigestion) may be used as fuels and increase the amount of lignocellulosic material available as feedstock in hydrolysis. The configuration of the cogeneration system (boiler pressure, lignocellulosic material consumption and steam production, turbines efficiencies, among others) has a significant impact on consumption of fuel and electricity output; in the integrated first and second generation, it also affects overall ethanol production. Simulations of the integrated first and second generation ethanol production processes were carried out using Aspen Plus, comparing different configurations of the cogeneration systems and pentoses use (biodigestion and fermentation). Economic analysis shows that electricity sale can benefit second generation ethanol, even in relatively small amounts. Environmental analysis shows that the integrated first and second generation process has higher environmental impacts in most of the categories evaluated than first generation. 相似文献
137.
In this article we explore the application of linear PI cascade control schemes to improve the performance of industrial PI/PID controllers for controlling outlet reactor concentration. By departing from simple I/O first-order dynamical models obtained from step responses, it is shown that the incorporation of a secondary loop for regulating the reactor temperature at a given interior position significantly improves the control performance in the face of feed composition and temperature disturbances. The effects of the temperature sensor location and the usage of multiple temperature measurements are also evaluated. 相似文献
138.
Edgardo D. Castronuovo Julio Usaola Ricardo Bessa Manuel Matos I.C. Costa L. Bremermann Jesus Lugaro George Kariniotakis 《风能》2014,17(6):829-852
The increasing wind power penetration in power systems represents a techno‐economic challenge for power producers and system operators. Because of the variability and uncertainty of wind power, system operators require new solutions to increase the controllability of wind farm output. On the other hand, producers that include wind farms in their portfolio need to find new ways to boost their profits in electricity markets. This can be done by optimizing the combination of wind farms and storage so as to make larger profits when selling power (trading) and reduce penalties from imbalances in the operation. The present work describes a new integrated approach for analysing wind‐storage solutions that make use of probabilistic forecasts and optimization techniques to aid decision making on operating such systems. The approach includes a set of three complementary functions suitable for use in current systems. A real‐life system is studied, comprising two wind farms and a large hydro station with pumping capacity. Economic profits and better operational features can be obtained from the proposed cooperation between the wind farms and storage. The revenues are function of the type of hydro storage used and the market characteristics, and several options are compared in this study. The results show that the use of a storage device can lead to a significant increase in revenue, up to 11% (2010 data, Iberian market). Also, the coordinated action improves the operational features of the integrated system. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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140.
Thatyane Vidal Fonteles Mayra Garcia Maia Costa Ana Laura Tibério de Jesus Cláudia Patrícia Mourão Lima Fontes Fabiano André Narciso Fernandes Sueli Rodrigues 《Food and Bioprocess Technology》2013,6(10):2860-2869
The use of sonicated melon juice as substrate for Lactobacillus casei growth in cantaloupe melon juice and its effect on product quality were investigated. The survival of L. casei in the fermented juice, the product color, the post-acidification and other quality parameters were evaluated in the refrigerated product (4 °C) for a period of 42 days. Storage pH, color, sugar content, lactic acid concentration, biomass and viable cells count were determined. The caloric value of the product was also evaluated. During the refrigerated storage period, acidification and a slight reduction in the number of viable cells were observed. However, a sufficient number of viable cells were observed to guarantee the beneficial properties from probiotic consumption (>8 log CFU?ml?1) throughout the storage period, for both stocked samples (with and without sugar addition). The product color was also preserved during storage. The developed product resulted in a low caloric product. The caloric value was reduced during the storage period due to sugar consumption by the remaining microorganisms. 相似文献