940 resultados para Box-Behnken experimental design


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The objective of this study was to evaluate the effect of Moringa oleifera Lam. leaf extract on the sedimentation of impurities in the treatment of sugarcane juice and the effects on sugar quality and on the clarified juice. The experimental design used was a 4x2 factorial arrangement with four replications. The main treatments performed included the extracted original sugarcane juice, the synthetic polyelectrolyte (Flomex 9076), the leaf extract, and a control. The secondary treatments consisted of the sugarcane varieties RB92579 and RB867515. The clarification process used was simple defecation, in which the flocculating agents and the juice, limed and heated, were poured simultaneously into a decanter. The microbiological and chemico-technological characteristics of the extracted and clarified juices were evaluated. The clarified juice was concentrated up to 60° Brix (syrup) and subjected to boiling in a pilot pan using seeds to perform the graining: The sugar was recovered by centrifugation and analyzed for microbiological and chemico-technological characteristics. It was concluded that the use of the Moringa oleifera Lam. leaves extract resulted in a better quality of clarified juice and sugar.

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Sugarcane juice with passion fruit pulp was clarified using microfiltration under different T (temperature), P (pressure), and V (tangential velocity). The effects of these processing parameters were evaluated applying a rotational central composite experimental design (RCCD) and response surface methodology (RSM). The tests were performed at a filtration pilot plant using a polyamide hollow-fiber membrane with an average pore diameter of 0.4 µm and filtration area of 0.723 m². In addition, the resistances to the permeate flux during the microfiltration were investigated according to the series resistance. The final permeate flux ranged from 7.05 to 17.84 L·h- 1·m- 2. There was a rapid decline in flux (50%) in the initial stages of microfiltration. T and V were the major variables responsible for the flux increase. The concentration polarization showed the greatest influence on the flux decline, and highest values for the flux decline rate (λ) were found when low pressures were used. In the clarified juice there was a reduction in the contents of total solids, proteins, vitamin C, and acidity, while the soluble solids, pH, and ash contents did not change. Finally, membrane process could produce high quality filtered sugarcane juice with substantial flux and increased luminosity improving organoleptical properties.

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In biotechnological processes, the culture media components are responsible for high costs and exert a strong influence on the cyanobacteria behavior. The objective of this study was to evaluate the Arthrospira platensis growth potential for biomass production under different cultivation conditions using an experimental design. Three factors that are important for cyanobacteria growth were evaluated: sodium bicarbonate (9 to 18 g/l), sodium nitrate (1.25 to 2.5 g/l), and irradiance (20 to 120 µmol photons/m2.s–1). The results showed that the concentration of NaNO3 in the A. platensis medium can be reduced, resulting in increased concentrations of biomass produced. There was a higher biomass production due to the increase in the concentration of NaHCO3 and irradiance, mainly when these two factors varied tending towards the highest values studied. The results demonstrate the potential to produce Arthrospira platensis with lower costs and effluent generation without affecting cultivation performance.

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The goal of this study was to determine the chemical composition of cashew apples agro-industrial residue and optimize the process of polyphenols extraction in this residue. The extraction process conditions were defined using a 24-1 fractional factorial experimental design using acetone and methanol as solvents. The independent variables were: time (30 to 90 min), temperature (30 to 50 °C), solvent concentrations (50% to 90%), agitation speed (100 to 300 rpm); the dependent variables were: total phenolic content and DPPH scavenging capacity. The optimized process was carried out by applying the Central Composite Rotational Design (CCRD) considering the results obtained with the 24-1 fractional factorial experimental design. The residue presented bioactive compounds in its composition, with emphasis on the content of total phenolic compounds (1975.64 mg/ 100 g). The extraction process was not affected by methanol; however, acetone affected the amounts of extracted phytochemicals. Extracts with high levels of polyphenols and strong DPPH scavenging capacity (> 80%) were obtained using 55% acetone, 30 minutes, 30 °C, and 150 rpm. The results showed that cashew apple residue is a potential natural source of bioactive compounds with strong antioxidant capacity. These compounds could be used partially or totally to replace synthetic antioxidants.

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AbstractThe objective of this study was to evaluate the genetic variability for synthesis of bioactive compounds in pepper (Capsicum annuum, Solanaceae). Total phenolics, anthocyanins, carotenoids and antioxidant activity were evaluated in 14 accessions of Capsicum annuum from the Capsicum Genebank of Embrapa Temperate Agriculture (Pelotas – RS, Brazil). Thirty plants of each accession were cultivated in the field during spring and summer. The experimental design was a complete randomized block with 14 treatments (accessions) and three replications. The laboratory evaluations followed the same experimental design to field, but with two repetitions more. Seeds were discarded and opposite longitudinal portions of fruits were manually prepared for chemical analyzes. The data obtained showed high genetic variability for phenolics, anthocyanins, carotenoids and antioxidant activity. The P39, P77, P119, P143 and P302 accessions exhibited the highest levels of antioxidants, which are strongly indicated to be used in breeding programs of Capsicum peppers.

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Abstract The camu-camu tree (Myrciaria dubia (Kunth) Mc Vaugh) is fruit-bearing tree belonging to the family Myrtaceae. This work was conducted with the purpose of evaluating the type of storage temperature and package which allow better conservation of the quality attributes of camu-camu. The experimental design utilized was the completely randomized with three replications in a factorial arrangement (3x3x8), constituted of three different storage temperatures (laboratory ambiente or 25 ± 2 °C, 15 °C and 20 °C), three types of packages (no package, PET and PVC) and fourteen days’ storage, the fruits being analyzed every two days. The fruits were evaluated as to fresh mass loss, pH, soluble solids contents, titrable acidity, ascorbic acid, carotenoids, anthocyanins, chlorophylls A and B and maturation index (SS/AT). According to the results obtained, the quality attributes and ascorbic acid content were conserved for longer time in the fruits stored on PVC-film covered expanded polystyrene trays at 15 °C. It follows that the best temperature for the storage of camu-camu is 15 °C and the package that best keeps its quality attributes is the PVC-film covered expanded polystyrene tray.

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Abstract Caprine Coalho cheese presents great potential for a typical protected designation of origin, considering that this traditional Brazilian cheese presents a slightly salty and acid flavor, combined with a unique texture. This study optimized the HS-SPME-GC-MS methodology for volatile analysis of Coalho cheese, which can be used as a tool to help in the identification of the distinctive aroma profile of this cheese. The conditions of equilibrium time, extraction temperature and time were optimized using the statistical tool factorial experimental design 23, and applying the desirability function. After the evaluation, it was concluded that the optimum extraction conditions comprised equilibrium and extraction time of 20 and 40 minutes, respectively; and ideal extraction temperature of 45 °C. The optimum extraction of volatile compounds in goat Coalho cheese captured 32 volatile compounds: 5 alcohols, 5 esters, 3 ketones, 6 acids, 3 aldehydes, 3 terpenes, and 7 hydrocarbons.

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The objective of this study was to verify the effect of drying on germination of cupuassu (Theobroma grandiflorum (Willd. ex Spreng) K. Schum.) seeds. Desiccation was in forced air oven, with temperature ranging from 23 to 33ºC. Sowing was carried out at 0.5cm of depth in plastic trays in sand and sawdust mixture (1:1), previously sterilized in hot water (100ºC), during 2h. Seeds were left to germinate in a laboratory with no temperature and relative humidity control, under natural light. It was quantified the seed moisture content, in four replications of 10 seeds; the germination percentage, performed during 30 days, with daily counts of the number of germinated seeds; the germination speed index; and number of days to the germination onset. The experimental design was completely randomized with four replications of 25 seeds. The reduction of moisture content from 58.6 to 37.8% did not affect seed germination and germination speed index; however, they were affected when moisture content was reduced to values below 30.7%. It was observed that only when moisture content was 16.1% seeds demanded more days to begin germination. Cupuassu seeds are classified as recalcitrant and they can be desiccated up to 37.8% with no reduction on germination.

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This experiment viewed to evaluate the physiological quality of grain sorghum seeds as well as to determine the respective drying curve of each of three drying methods. The seeds harvested at 18.9%, 18.1%, and 18.2% of moisture content were submitted to the following drying methods : a) under natural conditions, b) an intermittent dryer in which the combustion of firewood was the source of caloric energy, and c) a stationary dryer in which the source of caloric energy was the burning of liquefied petroleum gas. The experimental design was a completely randomized one with 25 repetitions of one hundred seeds each. The water contents and weight of one thousand seeds were evaluated. Seeds physiological quality was evaluated by germination and vigor tests. Seed drying rates were of 0.11, 1.25, and 0.55 percent points per hour (pph -1) for the natural, intermittent and stationary drying methods, respectively. The intermittent treatment permits the highest loss of water in the shortest period of time, and germination and vigor remaining unchanged.

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The impermeability of seed coat to water is common mechanism in Fabaceae seeds. Treatments to overcome hardseededness include scarification with sulphuric acid, scarification on abrasive surface and soaking in water among others. The objective of this study was to identify an effective method to overcome dormancy in Dinizia excelsa seeds. A pre-test (untreated seed) and three experiments were carried out: immersion of seeds in acid sulphuric for 10, 20, 30, 40, 50 and 60min (experiment 1); scarification on abrasive surface at the positions distal end, near of the mycrophyle and on the lateral tissue and tegument clipping at 1mm of the distal end, near of the mycrophyle and on the lateral tissue (experiment 2); scarification on abrasive surface and immersion in water for 0, 12, 24 and 48h (experiment 3). The experimental design was completely with four replications of 50 seeds for each treatment. The statistical analysis was carried out by ANOVA and regression analysis. Seedlings emergence on untreated seeds started on the 8th day after sowing and reached 52.5% on the 1,709th day. In general, the treatments to overcome dormancy increase emergence. Emergence was higher for seeds treated with sulphuric acid for 20 and 30min with emergence of 93.6% and 86.6%, respectively. For seeds scarified on abrasive surface higher emergences were recorded for scarification on distal end, near of the mycrophyle and on the lateral, 82.7%, 74.3% and 75.7%, respectively. Seeds scarified manually showed higher emergence when not immersed in water (75%), or when immersed for 12 and 24h (75%, 73.6% and 65.6%, respectively). Immersion seeds in sulphuric acid for 20 and 30min and scarification on abrasive surface of distal end are effective to overcome dormancy in D. excelsa.

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The use of unconventional sources of K for plants has been widely studied, but the effects of alternative materials on physiological seed quality are still relatively unknown. The objective of this study was to evaluate the physiological quality of soybean and wheat seeds after using different potassium sources in a crop succession. The experimental design was a completely randomized block with four replications. Treatments consisted of three K sources (KCl, alkaline rock and ground phonolite, with 58%, 11% and 8.42% of K2O, respectively) applied in four doses (0, 25, 50 and 100 kg K2O ha-1). Potassium doses were applied in soybean and their residual effects were evaluated on the following wheat crop. Soybean and wheat seeds were evaluated immediately after harvesting by tests for moisture content, seed weight, germination, first count, electrical conductivity, seedling length and seedling dry matter. Soybean plants fertilized with alternative sources of K produced heavier seeds with a lower coat permeability compared to KCl; the physiological quality of soybean seeds and the weight of wheat seeds increase due to higher K2O doses, independently of their source.

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The objective of this study was to evaluate the performance of seeds of two cultivars of lowland rice (Oryza sativa L.), coated with dolomitic limestone and aluminum silicate. It was used a completely randomized experimental design, with the treatments arranged in a 4 X 2 factorial scheme [4 treatments: dolomitic limestone; dolomitic limestone + aluminum silicate; aluminum silicate, at the dosages of 50 g/100 kg of seeds; and control (without the products) X 2 cultivars: IRGA424 and IRGA 422 CL], totaling eight treatments with four replications each. The variables analyzed were: fresh and dry weights of aerial biomass; plant height; leaf area at 10, 20, and 30 days after emergence (DAE). The physiological quality of seeds was also assessed using tests of: seed emergence; first count of germination; emergence speed index; and field emergence. It was concluded that the coating of rice seeds with dolomitic limestone and aluminum silicate does not affect seed germination and field seedling emergence. Aluminum silicate used via seed coating on cultivar IRGA 424 promoted greater leaf area, after 20 DAE. The dolomitic limestone and the aluminum silicate used via seed coating generated plants with larger dry biomass, after 20 DAE, for the cultivar IRGA 422 CL.

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The objective of this study was to investigate the possibility of using hydric restriction as a method for evaluating vigor of soybean seeds. The soybean seeds, cultivar BRS 245RR, represented by four different seed lots, were characterized by germination and vigor. For the treatment of hydric restriction and temperature, the combination of substrate water potential and temperature were the following: deionized water (0.0 MPa); polyethylene glycol (PEG 6000) aqueous solution (-0.1, -0.3 and -0.5 MPa); and four temperatures (20 ºC, 25 ºC, 30 ºC, and 35 ºC), respectively. A completely randomized experimental design was used, with four replications per treatment, and the ANOVA was performed individually for each combination of temperature and water potential of substrate. According to results obtained, the test of hydric restriction has the same efficiency of the accelerated aging test in estimating vigor of soybean seeds, cv. BRS 245RR, when water potentials of -0.1 MPa or -0.3 MPa at a temperature of 25 ºC, or -0.3 MPa at a temperature of 30 ºC are used.

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In consequence of several studies and speculations concerning the issue of RR transgenic soybean after the application of glyphosate, additional scientific investigations became necessary to clarify the actual viability of the product use when applied in different developmental stages of the soybean crop. Therefore, this study was aimed to evaluate the physiological quality as well as seed health quality of RR soybean subjected to application of the herbicide glyphosate in different phonological stages of the transgenic soybean, cultivar CD 219RR. For this, an experiment with a complete block experimental design with treatments randomly distributed within the block, with four replications, was carried out. The assessed treatments were foliar sprayings of glyphosate in three increasing dosages [0 (control); 1,440 g ha-1; and 2,880 g ha-1] of acid equivalent, applied in two crop developmental stages: vegetative (V6) and reproductive (R2). The variables assessed were: germination; first count of germination; fresh and dry mass of seedlings, lengths of seedling and root; vigor and viability by the tetrazolium test; and seed health quality. Glyphosate application may adversely affect physiological quality of RR soybean seeds, when applied in dosages varying from 1,440 to 2,880 g acid equivalent per hectare at the stages V6 and R2.

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The purpose of this two-phased study is to examine the interest of nursing students in choosing a career in older people nursing. First, the scoping phase explores the different premises for choosing older people nursing as a career. Second, the evaluation phase investigates the outcomes of the developed educational intervention involving older people as promoters of choosing a career in older people nursing, factors related to these outcomes, and experiences with educational intervention. The ultimate goal is to encourage more nursing students to choose older people nursing as their career. The scoping phase applies an exploratory design and centres around a descriptive, cross-sectional survey, documentary research and a scoping literature review. The information sources for this phase include 183 nursing students, 101 newspaper articles and 66 research articles. The evaluation phase applies a quasi-experimental design and a pre-post-test design with a non-equivalent comparison group and a post-intervention survey. The information sources for this phase include 87 nursing students and 43 older people. In both phases, statistical and narrative methods are applied in the data analysis. Nursing students neutrally regarded the idea of a career in older people nursing. The most consistent factors related to the nursing students’ career plans in older people nursing were found to be nursing work experience and various educational preparations in the field. Nursing students in the intervention group (n=40) were more interested in older people nursing and had more positive attitudes towards older people than did students in the comparison group (n=36). However, in both groups, the interest that students had at the baseline was associated with the interest at the one-month follow-up. There were no significant differences between the groups in terms of the students’ knowledge levels about ageing. The nursing students and older people alike highly appreciated participating in the educational intervention. It seems possible to positively impact nursing students and their choices to pursue careers in older people nursing, at least in the short-term. The involvement of older people as promoters of this career choice provides one encouraging alternative for impacting students’ career choices, but additional research is needed.