Classificação de água de coco processada e natural por meio de HCA, PCA e teores de íons metálicos determinados por ICP OES

Inductively Coupled Plasma Optical Emission Spectrometry was used to determine Ca, Mg, Mn, Fe, Zn and Cu in samples of processed and natural coconut water. The sample preparation consisted in a filtration step followed by a dilution. The analysis was made employing optimized instrumental parameters and the results were evaluated using methods of Pattern Recognition. The data showed common concentration values for the analytes present in processed and natural samples. Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) indicated that the samples of different kinds were statistically different when the concentrations of all the analytes were considered simultaneously.

Caracterização de dois equipamentos de beneficiamento e classificação de tomates para mesa

On the last years, in Brazil, sorting and classifying fruits and vegetables using packing lines have increased. This work aimed at characterizing the cleaning process for fresh market tomatoes at two packing lines, one imported and one national located at Campinas, São Paulo State. Characterization included data, number, types and brushes velocity, water use, fruit standing time and cleaning efficiency. Standing time was measured correlating to fruit diameter (CEAGESP). For measuring cleaning efficiency an equipment was developed that was mainly composed of a ring involved with white cloth. Samples were taken before and after the cleaning step and evaluated using a colorimeter HUNTER Lab. The results showed a strong difference between the two equipments. The imported equipment showed lower number on brushes and rotation than national one, however a higher water consumption. For imported equipments this relation was not found. Both packing lines showed the same cleaning efficiency. Cleaning efficiency is related to be an interaction among the studies parameters, and it could be necessary a better management than the one used on both equipments.

O estado da arte da cromatografia associada à espectrometria de massas acoplada à espectrometria de massas na análise de compostos tóxicos em alimentos

Chromatography combined with several different detection systems is one of the more used and better performing analytical tools. Chromatography with tandem mass spectrometric detection gives highly selective and sensitive analyses and permits obtaining structural information about the analites and about their molar masses. Due to these characteristics, this analytical technique is very efficient when used to detect substances at trace levels in complex matrices. In this paper we review instrumental and technical aspects of chromatography-tandem mass spectrometry and the state of the art of the technique as it is applied to analysis of toxic substances in food.

Sulfetos volatilizáveis por acidificação e metais extraídos simultaneamente na avaliação de sedimentos de água doce

This paper discusses the historical and methodological fundaments of the dynamics and quantification of acid volatile sulfides (AVS) and simultaneously extracted metals (SEM) in aquatic sediments. It also discusses the SEM/AVS relationship, which involves several controversial aspects such as sulfide stability, sulfide-organic matter interaction, and the inability to predict the toxicity of organic compounds in the environment. This relationship is an important tool for the inference of metal bioavailability. The use of ecotoxicological tests with target organisms regulated by international standards is also a relevant aspect.

Atribuição absoluta e geral de isômeros constitucionais por espectrometria de massas: o caso das metilpiperidinas

An absolute method is described via mass spectrometry (MS) for the structural assignment of isomers within the class of methylpiperidines. The method explores both the unimolecular and bimolecular gas phase behavior of structurally diagnostic fragment ions (SDFI). For the methylpiperidnes, the isomeric 2-methyl, 3-methyl and 4-methyl 2-azabutadienyl cations are found to function as SDFI. These fragment ions are expected to be formed from all members within the class, to be stable and to retain the structural information of the precursor molecule, and to not interconvert into one another. To characterize these SDFI, both the collision induced dissociation (CID) in argon and bimolecular ion/molecule chemistry with ethyl vinyl ether were compared.

Avaliação de técnicas de classificação digital de imagens landsat em diferentes padrões de cobertura da terra em Rondônia

Remotely sensed imagery has been widely used for land use/cover classification thanks to the periodic data acquisition and the widespread use of digital image processing systems offering a wide range of classification algorithms. The aim of this work was to evaluate some of the most commonly used supervised and unsupervised classification algorithms under different landscape patterns found in Rondônia, including (1) areas of mid-size farms, (2) fish-bone settlements and (3) a gradient of forest and Cerrado (Brazilian savannah). Comparison with a reference map based on the kappa statistics resulted in good to superior indicators (best results - K-means: k=0.68; k=0.77; k=0.64 and MaxVer: k=0.71; k=0.89; k=0.70 respectively for three areas mentioned). Results show that choosing a specific algorithm requires to take into account both its capacity to discriminate among various spectral signatures under different landscape patterns as well as a cost/benefit analysis considering the different steps performed by the operator performing a land cover/use map. it is suggested that a more systematic assessment of several options of implementation of a specific project is needed prior to beginning a land use/cover mapping job.

Classificação e padronização dos tomates cv. Carmem e Débora dentro da CEAGESP - SP

The creation of the Brazilian Program for the Modernization of the Horticulture by the Secretariat of Agriculture and Supplying of the State of São Paulo at CEAGESP, determined the standardization of fruit and vegetables in the follow aspects: degree of coloration, format, calibers, defects and packing. Therefore, the main goal of this research is to correlate the classification given by the Brazilian Program with the one used by the wholesalers at CEAGESP, verifying if the established norms are being fulfilled for cultivar Carmen and Debora (SAKATA SEED). The results showed, that for cultivar Carmem, for the averages of the observed values it does not move away from the norms created by the Program for sizes small and medium. However, for the case of cultivar Debora, the results showed differences between the adopted classifications. The tomatoes were devaluated, because had been commercialized below of the standardization indicated for the Brazilian Program.

Efeitos da cobertura do solo com filme de polietileno azul no consumo de água da cultura da alface cultivada em estufa

The covering of the soil is an agricultural practice that intends to control the harmful herbs, to reduce the losses of water by evaporation of the soil, and to facilitate the harvest and the commercialization, once the product is cleaner and healthier. However, when the soil is covered important microclimatic parameters are also altered, and consequently the germination of seeds, the growth of roots, the absorption of water and nutrients, the metabolic activity of the plants and the carbohydrates storage. The current trial intended to evaluate the effect of soil covering with blue colored film on consumptive water-use in a lettuce crop (Lactuca sativa, L.). The experiment was carried out in a plastic greenhouse in Araras - São Paulo State, Brazil from March 3rd, 2001 to May 5th, 2001. The consumptive water-use was measured through two weighing lysimeter installed inside the greenhouse. Crop spacing was 0.25 m x 0.25 m and the color of the film above soil was blue. Leaf area index (IAF), was measured six times (7; 14; 21; 28; 35; 40 days after transplant) and the water-use efficiency (EU) was measured at the end. The experimental design was subdivided portions with two treatments, bare soil and covered soil. The average consumptive water-use was 4.17 mm day-1 to the bare soil treatment and 3.11 mm day-1 to the covered soil treatment. The final leaf area index was 25.23 to the bare soil treatment and 24.39 to the covered soil treatment, and there was no statistical difference between then.

Teores de nutrientes na alface irrigada com água residuária aplicada por sistemas de irrigação

A trial was carried out to evaluate the chemical composition in the aerial part of lettuce, cv. 'Elisa', irrigated with wastewater treated with constructed wetland and source deposit water, grown on a Rhodic Hapludox Soil, using the irrigation systems sprinkle, subsurface drip and surface drip irrigation. The experiment was carried out from August 17th to October 3rd of 2001 and the chemical analyses of the lettuce were accomplished to 47 days after transplanting of the seedling. The aerial part of the lettuce was analyzed as for the levels of total nitrogen, nitrate, phosphorus, potassium, calcium, magnesium, sulfur, iron, manganese, copper, zinc, sodium, boron, cobalt and molybdenum. The sodium and the sulfur presented higher levels than the maximum suitable in the aerial part of the lettuce and the smallest level of magnesium, while other chemical elements analyzed were normal and appropriate considering the standard for well-nourished plants, not being influenced by the water type. The sodium was the chemical element that presented the highest levels in the aerial part of the lettuce in the treatments irrigated with wastewater, presenting significant difference in relationship to the treatments irrigated with source deposit water in the three irrigation systems. The use of the different irrigation systems by the application of wastewater treated with constructed wetland did not interfere in the levels of nutrients in the aerial part of the lettuce.

Qualidade da classificação do tomate de mesa em unidades de beneficiamento

Quality evaluation of classification was done in two fresh market tomatoes packing house, using electronically and mechanical equipments in two harvest periods, summer and winter seasons. The main goal of this work was to evaluate size and color grading conformity with the standards proposed by the Brazilian Program for Horticulture Modernization and size grading obtainded with the one established by the packer. The cultivar studied was Carmen. The results showed that there was no grade conformity with the fresh tomato quality standards proposed by the Brazilian Program for Horticulture Modernization. The grade conformity obtained when compared with the one programmed by the packer, was only for large sizes, in both equipments. The electronically equipment has presented better performance, over the mechanical, considering grading quality and fruits post-harvest quality. However, the electronically equipment must be constantly monitored to achieve efficiency and investment return. On the other side, for mechanical equipment it will be necessary to review the actual system of size grading, in order to follow the fresh tomato quality standards.

Influência da temperatura do ar de secagem no calor latente de vaporização de água em feijão macassar (Vigna unguiculata (L.) Walp.), variedade sempre-verde

In order to determine the energy needed to artificially dry an agricultural product the latent heat of vaporization of moisture in the product, H, must be known. Generally, the expressions for H reported in the literature are of the form H = h(T)f(M), where h(T) is the latent heat of vaporization of free water, and f(M) is a function of the equilibrium moisture content, M, which is a simplification. In this article, a more general expression for the latent heat of vaporization, namely H = g(M,T), is used to determine H for cowpea, always-green variety. For this purpose, a computer program was developed which automatically fits about 500 functions, with one or two independent variables, imbedded in its library to experimental data. The program uses nonlinear regression, and classifies the best functions according to the least reduced chi-squared. A set of executed statistical tests shows that the generalized expression for H used in this work produces better results of H for cowpea than other equations found in literature.

Adequação de engates rápidos de aspersores como conectores de mangueira para distribuição de água em sulcos de irrigação

As a way to reduce water losses in furrow irrigation systems, used in fresh market tomato production, farmers are improperly distributing water into the field using plastic hose. The objective of this work was to study the suitability of using quick coupler sprinkler as hose connectors for water distribution in tomato plantation. The first step of the study was to assess the current hose field operation for tomato growers. Subsequently, four models of quick couplers sprinklers available in the market were tested in laboratory to determine the coefficient of resistance, the equivalent tube length, the head loss curve and the linking efficiency. As result, a structural design for hose connectors was presented using the model of coupling with the best hydraulic performance. Additionally, some technical recommendations on its use in irrigation water distribution are highlighted. Despite the requirement for additional field trials, the proposed system has potential to optimize the water use efficiency, to improve workers ergonomic conditions, and ensure good profitability to the producer.

Por uma lingüística crítica: linguagem, identidade e questão ética

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Variação sazonal da fotossíntese, condutância estomática e potencial da água na folha de laranjeira 'Valência'

Seasonal variation in environmental conditions may influence gas exchange rates as well as water relations in perennial species. This work was carried out to evaluate photosynthetic rates (A), transpiration (E), stomatal conductance (g) and leaf water potential (psi f ) in 'Valencia' orange trees grafted on four different rootstocks. Measurements were made twice a day: from 9h00 to 11h00 a.m. and from 1h00 to 3h00 p.m., during January, March and July. A and g were significantly lower and psif was significantly more negative, in the afternoon. The decrease in A may be related to the reduction in g, due to the increase in the vapor pressure deficit between the air and the leaf (VPDair-leaf ) in the afternoon, when temperatures are higher. In spite of the partial stomatal closure in the afternoon, the values for E were approximately the same as those measured in the morning, due to the increase in the VPDair-leaf . A decrease in A and g could also be noted from January to July, that is, from the hot and humid summer months, to the colder and drier winter ones. It was suggested that the decrease in A and g observed from January through March, may be related to the decrease in plant growth rates, which could have influenced the source-sink relationships, since the climatic conditions for both months were similar. The decrease in A and g showed in July, seems to be related to the decrease in both the night temperature and the growth rate of plants.

PREDIÇÃO DA ATIVIDADE DE ÁGUA E RELAÇÃO ENTRE A ATIVIDADE DE ÁGUA E A DEPRESSÃO DO PONTO DE CONGELAMENTO DE SUCOS DE FRUTAS

This work proposes to determine the water activity and the freezing point depression of tangerine, pineapple and lemon juices at various concentrations (10-55oBrix) and to achieve a correlation between these properties. The freezing point depression was determined with a LAKTRON cryoscope and common laboratory materials. The water activity was determined with a DECAGON CX-2 hygrometer in the temperature range of 15 to 30oC. With the results, the adjustment to CHEN (1987) water activity prediction equation to non-electrolyte mixtures was verified, through the calculation of the variation coefficient (CV). Being CV smaller than 3% for the proposed model, it can be said that the experimental data have adjusted well to the prediction equation. The water activity and the freezing point depression was correlated for tangerine, pineapple and lemon juices and r2 values were higher than 99%. Therefore, it is possible to obtain the water activity by knowing the freezing point depression of studied juices.