RESUMO:Esse trabalho teve como objetivo avaliar diferentes modelos matemáticos para determinar a curva de secagem de guaco. Para a condução do experimento, foi utilizado um secador com ventilação forçada, com 4 bandejas, empregando gás liquefeito de petróleo como fonte de aquecimento. Foram realizados 6 tratamentos de secagem: com ar aquecido a 40, 50, 60, 70 e 80ºC, e com ar a temperatura ambiente. Para todos os tratamentos a velocidade do ar de secagem passando através da massa de plantas foi mantida em, aproximadamente, 0,5 m s -1 . Para ajuste dos modelos matemáticos aos dados experimentais realizou-se análise de regressão não-linear pelo método Quasi-Newton empregando-se o programa computacional STATISTICA 6.0 ® , sendo os valores dos parâmetros dos modelos estimados em função da temperatura do ar de secagem. Apenas o modelo proposto por Midilli et al. apresentou ajuste satisfatório para descrever o processo de secagem de guaco, independentemente da temperatura do ar de secagem, enquanto o modelo da aproximação da difusão se adequou para a temperatura ambiente e com ar aquecido a 60ºC. Palavras-chave: Plantas medicinais, modelos matemáticos, cinética de secagemABSTRACT: Evaluation of drying curves of Mikania glomerata Spreng. in a tray dryer. This work aimed to evaluate different mathematical models to determine the curve of the drying of Mikania glomerata Spreng. . For the conduction of the experiment, a drier with forced ventilation was used, with 4 trays, using liquefied petroleum gas as heating source. Six drying treatments were carried out, that is, with hot air at 40, 50, 60, 70 and 80ºC, as well as drying with air at room temperature. For all the treatments, the drying air speed, through the mass of plants, were kept at, approximately, 0.5 m s -1 . For the adjustment of the mathematical models to the experimental data, nonlinear regression analysis was performed through the Quasi-Newton method, using the computational program STATISTICA 6.0 ® , and the values of the parameters of the models were estimated in function of the temperature of the drying air. But only the model considered by Midilli et al. presented satisfactory adjustment to describe the process of drying Mikania glomerata Spreng., regardless of the temperature of the drying air, while the model of diffusion approximation was suitable for room temperature and hot air at 60ºC.
Influência do processo de secagem sobre os principais componentes químicos do óleo...Rev. Ceres, Viçosa, v. 59, n.5, p. 731-737, set/out, 2012 RESUMO ABSTRACT Influence of the drying process on the quality of thyme essential oilThe study aimed to evaluate the effect of drying air temperature on the quality of the essential oil from thyme leaves. Different drying temperatures (30, 40, 50, 60, 70 ºC) were applied in a dryer with electrical resistance heater. After drying, the chemical components of the essential oil were compared with those obtained from fresh samples (control). The extraction of the essential oil was performed using the supercritical CO 2 method. The identification of the essential oil components was carried out by gas chromatography coupled to mass spectrometry (GC-MS) and the quantification by gas chromatography coupled to a flame ionization detector (GC-FID). According to the results, it is recommended the drying air temperature of 60 ºC for drying thyme leaves . Objetivou-se, com este trabalho, avaliar o efeito da temperatura do ar de secagem sobre a qualidade do óleo essencial de folhas de tomilho. Foram empregadas diferentes temperaturas de secagem (30, 40, 50, 60, 70 ºC), em um secador com resistências elétricas. Os componentes químicos do óleo essencial, depois de realizada a secagem, foram comparados com os valores obtidos na planta in natura (testemunha). Para a extração do óleo essencial, foi empregado o método de extração com CO 2 supercrítico. A identificação dos componentes químicos do óleo essencial foi realizada por cromatografia gasosa, acoplada ao espectrofotômetro de massas (CG-EM) e, para a quantificação desses componentes, empregou-se o cromatógrafo a gás, acoplado ao detector por ionização de chamas (CG-DIC). Em função dos resultados obtidos, recomenda-se ar, à temperatura de 60 ºC, para a secagem das folhas de tomilho.Palavras-chave: plantas medicinais, temperatura do ar de secagem, Thymus vulgaris.
Fungi are one of the main food spoilage agents. Numerous species when subjected to stress conditions produce secondary metabolites known as mycotoxins, which are mutagenic and carcinogenic substances. The fungus Aspergillus flavus is one of the main contaminants of grains and is known to produce Aflatoxin. Pesticides are used in agriculture to contain fungi and other pests, but they harm other species, the environment and the human health, in addition to the development of resistance to these substances in pest species. Natural alternatives have been sought to control these organisms. In this context, essential oils are a viable option against A. flavus. The aim of this study was to identify the main components and evaluate the effectiveness of lemongrass essential oil (Cymbopogon flexuosus) for controlling the fungus Aspergillus flavus. Initially, the effect of essential oil on mycelial growth of the fungus was assessed by in vitro tests at the doses: 0.05; 0.1; 0.2; 0.4; 0.6; 0.8; 1.6; 3.2; 6.4; and 12.8 μL mL-1. The minimum inhibitory concentration (MIC) was 0.8 μL mL-1. The in vivo test was performed at the following concentrations: 0.6; 0.8; and 1.6 μL mL-1. The results showed that the essential oil has fungicidal potential against A. flavus. The main component of the essential oil was citral.
Seed quality is a key factor to succeed in a yield generation and storage is an important activity to control the physiological seed quality, as it preserves seed viability while maintaining its robustness at a reasonable level between planting and harvest. On this basis, the goal of this study was to evaluate the physiological quality of snap bean seeds stored in different types of packages and storage conditions. Eight genotypes comprising six lines and two controls were analyzed. It was applied a completely randomized block design with four replicates in a factorial scheme (8×2×2×7).Seed storage was performed in permeable and impermeable packages under controlled and uncontrolled conditions. The physiological seed quality was evaluated by means of germination and vigor tests. The different types of package and storage conditions influenced the physiological seed quality. Under controlled storage conditions, the permeable and impermeable packages were more efficient in controlling the physiological quality of snap bean seeds.
, VINICIUS OLIVEIRA CARLESSO 4 , MÁRCIA TEREZINHA RAMOS OLIVEIRA 5 RESUMO -O desenvolvimento de modelos matemáticos que correlacionem a permissividade elétrica relativa ε' e o fator de perda dielétrica ε" à quantidade de água presente em amostras de sementes é um passo fundamental no desenvolvimento de medidores em linha do teor de água que possam ser empregados no controle automático de processos como colheita, secagem e aeração. Esse trabalho consistiu na avaliação de três modelos dielétricos para determinação do teor de água de sementes de café, sem a influência do fluxo de massa. Foram utilizadas amostras das variedades Catuaí Amarelo, Catuaí Vermelho e Mundo Novo, com teores de água entre 11 e 23% b.u. e massa específica aparente no intervalo 326 kg m -3 < ρ < 455 kg m -3. Dos modelos obtidos, apenas aquele que utiliza a medição simultânea de ε' e ε", a 0,5 e 5,0 MHz, permite estimar o teor de água de sementes de café com o grau de acurácia desejado. Os erros padrão de calibração e predição foram de 1,3 e 1,2 pontos percentuais, respectivamente.Termos para indexação: Coffea arabica, umidade, propriedades dielétricas, instrumentação. MOISTURE DETERMINATION IN COFFEE SEEDS BY THE CAPACITANCE METHOD AT RADIOFREQUENCIESABSTRACT -The development of mathematical models capable of relating the relative permittivity ε' and the loss factor ε" of seeds to their moisture content is a fundamental step towards designing seed moisture meters for on-line operations in automatic control processes such as seed harvest, drying and aeration. The object of this research is the assessment of three dielectric models that would allow the density-independent determination of the moisture content of moving seeds of parchment coffee. Seed samples of varieties Catuaí Amarelo, Catuaí Vermelho and Mundo Novo with moisture contents in the range from 11 to 23% w.b., and bulk density ranging from 326 to 455 kg.m -3 have been used. In terms of instrumentation accuracy the best bulk-density dielectric model for coffee seeds moisture content estimation was the one which employed both ε' and ε" measured at 0.5 and 5.0 MHz as indicators of the amount of water present in the seed samples. The standard errors of calibration and prediction were 1.3 and 1.2 percentage points moisture, respectively
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.