Chemical characteristics of grape juices from different cultivar and rootstock combinations

The objective of this work was to evaluate the influence of different combinations of grape cultivars and rootstocks on chemical characteristics of grape juices. Six treatments were evaluated, consisting of combinations between the Isabel Precoce and BRS Cora grape cultivars and the 'IAC 766', 'IAC 313', and 'IAC 572' rootstocks. Approximately 10 L of juice were obtained per treatment. Analyses of color, total soluble solids content, pH, anthocyanins, total phenolics, total sugars, and quantification and identification of biogenic amines by HPLC were performed. Biogenic amines, such as putrescine, cadaverine, spermidine, and spermine, were found in all evaluated cultivars. By principal component analysis (PCA), treatments can be divided into two groups, according to the cultivar. Juices obtained from 'Isabel Precoce' are characterized by higher levels of total sugar content and soluble solids; however, juices from 'BRS Cora' are positively correlated with phenolic content, anthocyanins, and color and acidity parameters. The differences found by PCA for juices from the Isabel Precoce and BRS Cora cultivars indicate that, regardless of the rootstock used, the most important factor in the chemical characterization of juices is the grape cultivar.

Potassium fertilization for pineapple: effects on soil chemical properties and plant nutrition

A field experiment was carried out on an Ultisol located at the city of Agudos (22º30'S; 49º03'W), in the state of São Paulo, Brazil, in order to determine the effects of rates and sources of potassium fertilizer on nutritional status of 'Smooth Cayenne' pineapple and on some soil chemical properties. The experiment was a complete factorial design with four rates (0, 175, 350, and 700 kg ha-1 of K2O) and three combinations of K sources (100% KCl, 100% K2SO4 and 40% K2SO4 + 60% KCl). Soil samples were taken from the depths 0-20 cm, 20-40 cm and 40-60 cm at planting and 14 months after. Nutritional status of pineapple plants was assessed by means of tissue analysis. Soil K availability increased with application of K fertilizer, regardless of K sources. Soil chlorine and Cl concentration in pineapple leaves increased with application of KCl or K2SO4+KCl. Plant uptake of potassium was shaped by soil K availability and by the application rates of K fertilizer, independently of K sources.

Yield mapping, soil fertility and tree gaps in an orange orchard

The current high competition on Citrus industry demands from growers new management technologies for superior efficiency and sustainability. In this context, precision agriculture (PA) has developed techniques based on yield mapping and management systems that recognize field spatial variability, which contribute to increase profitability of commercial crops. Because spatial variability is often not perceived the orange orchards are still managed as uniform and adoption of PA technology on citrus farms is low. Thus, the objective of the present study was to characterize the spatial variability of three factors: fruit yield, soil fertility and occurrence of plant gaps caused by either citrus blight or huanglongbing (HLB) in a commercial Valencia orchard in Brotas, São Paulo State, Brazil. Data from volume, geographic coordinates and representative area of the bags used on harvest were recorded to generate yield points that were then interpolated to produce the yield map. Soil chemical characteristics were studied by analyzing samples collected along planting rows and inter-rows in 24 points distributed in the field. A map of density of tree gaps was produced by georeferencing individual gaps and later by counting the number of gaps within 500 m² cells. Data were submitted to statistical and geostatistical analyses. A t test was used to compare means of soil chemical characteristics between sampling regions. High variation on yield and density of tree gaps was observed from the maps. It was also demonstrated overlapping regions of high density of plant absence and low fruit yield. Soil fertility varied depending on the sampling region in the orchard. The spatial variability found on yield, soil fertility and on disease occurrence demonstrated the importance to adopt site specific nutrient management and disease control as tools to guarantee efficiency of fruit production.

Repeatability, correlation and path analysis of physical and chemical characteristics of peach fruits

This study aimed to determine the number of measurements necessary to evaluate physical and chemical characteristics of peach fruits, study the relationships between them and their direct and indirect effects on the content of ascorbic acid and total carotenoids. The characteristics skin and pulp color, fruit weight, suture, equatorial and polar diameters, firmness, soluble solids (SS), titratable acidity (TA), SS/TA ratio, ascorbic acid and total carotenoids were evaluated in 39 cultivars of peach and 3 cultivars of nectarine from the orchard of the Universidade Federal de Viçosa. The repeatability coefficient was estimated by ANOVA and CPCOR. Phenotypic correlation coefficients (rf) were estimated and, after the multicollinearity diagnostics, they were unfolded to direct and indirect effects of the explanatory variables on the response variable using path analysis. There was agreement on the magnitude of repeatability coefficients obtained by the two methods; however, they varied among the 14 characteristics. The highest correlations were found between FW, SD, ED and PD. Seven fruits are sufficient to evaluate the physical and chemical characteristics of peach with a correlation coefficient of 90%. The characteristics considered in the path diagrams (b* skin, hº skin, b* pulp, hº pulp, ED, PD, FIR, SS, SS/AT and TC) are not the main determinants of the ascorbic acid. The yellow hue of the pulp (hº pulp) has the potential to be used in indirect selection for total carotenoids.

Distribution of chemical compartments of soil organic matter and c stocks of a cambisol from south Brazil as affected by Pinus afforestation

Distribution and stocks of soil organic matter (SOM) compartments after Pinus monoculture introduction in a native pasture area of a Cambisol, Santa Catarina, Brazil, were investigated. Pinus introduction increased soil acidity, content of exchangeable Al+3 and diminished soil nutrients. Nevertheless, soil C stock increased in all humic fractions of the 0-5 cm layer after Pinus afforestation. In the subsurface, the vegetation change only promoted SOM redistribution from the NaOH-extractable humic substances to a less hydrophobic humin fraction. Under Pinus, soil organo-mineral interactions were relevant up to a 15 cm depth, while in pasture environment, this mechanism occurred mainly in the surface layer.

Chemical characteristics and Kraft pulping of tension wood from Eucalyptus globulus labill

Tension (TW) and opposite wood (OW) of Eucalyptus globulus trees were analyzed for its chemical characteristics and Kraft pulp production. Lignin content was 16% lower and contained 32% more syringyl units in TW than in OW. The increase in syringyl units favoured the formation of β-O-4 bonds that was also higher in TW than in OW (84% vs. 64%, respectively). The effect of these wood features was evaluated in the production of Kraft pulps from both types of wood. At kappa number 16, Kraft pulps obtained from TW demanded less active alkali in delignification and presented slightly higher or similar pulp yield than pulps made with OW. Fiber length, coarseness and intrinsic viscosity were also higher in tension than in opposite pulps. When pulps where refined to 30°SR, TW pulps needed 18% more revolutions in the PFI mill to achieve the same beating degree than OW pulps. Strength properties (tensile, tear and burst indexes) were slightly higher or similar in tension as compared with opposite wood pulps. After an OD0(EO)D1 bleaching sequence, both pulps achieved up to 89% ISO brightness. Bleached pulps from TW presented higher viscosity and low amount of hexenuronic acids than pulps from OW. Results showed that TW presented high xylans and low lignin content that caused a decrease in alkali consumption, increase pulp strength properties and similar bleaching performance as compared with pulps from OW.

Terrain forms and spatial variability of soil properties in an area cultivatedwith citrus

The technique of precision agriculture and soil-landscape allows delimiting areas for localized management, allowing a localized application of agricultural inputs and thereby may contribute to preservation of natural resources. Therefore, the objective of this work was to characterize the spatial variability of chemical properties and clay content in the context of soil-landscape relationship in a Latosol (Oxisol) under cultivation of citrus. Soil samples were collected at a depth of 0.0-0.2 m in an area of 83.5 ha planted with citrus, as a 50-m intervals grid, with 129 points in concave terrain and 206 points in flat terrain, totaling 335 points. Values for the variables that express the chemical characteristics and clay content of soil properties were analyzed with descriptive statistics and geostatistical modeling of semivariograms for making maps of kriging. The values of range and kriging maps indicated higher variability in the shape of concave topography (top segment) compared with the shape of flat topography (slope and hillside segments below). The identification of different forms of terrain proved to be efficient in understanding the spatial variability of chemical properties and clay content of soil under cultivation of citrus.

Management zones in agriculture acording to the soil and landscape variables

The study of spatial variability of soil and plants attributes, or precision agriculture, a technique that aims the rational use of natural resources, is expanding commercially in Brazil. Nevertheless, there is a lack of mathematical analysis that supports the correlation of these independent variables and their interactions with the productivity, identifying scientific standards technologically applicable. The aim of this study was to identify patterns of soil variability according to the eleven physical and seven chemical indicators in an agricultural area. It was used two multivariate techniques: the hierarchical cluster analysis (HCA) and the principal component analysis (PCA). According to the HCA, the area was divided into five management zones: zone 1 with 2.87ha, zone 2 with 0.8ha, zone 3 with 1.84ha, zone 4 with 1.33ha and zone 5 with 2.76ha. By the PCA, it was identified the most important variables within each zone: V% for the zone 1, CTC in the zone 2, levels of H+Al in the zone 4 and sand content and altitude in the zone 5. The zone 3 was classified as an intermediate zone with characteristics of all others. According to the results it is concluded that it is possible to separate into groups (management zones) samples with the same patterns of variability by the multivariate statistical techniques.

Water distribuition characteristics and soil loss of LEPA Quad-Spray emitter nozzles

The objective of this study was to characterize water application rate, water application pattern width, flow rate, water distribution uniformity and soil loss caused by nozzles of the Low Energy Precision Aplication (LEPA) type Quad-Spray emitter. The study was carried out at the Hydraulic and Irrigation Laboratory of the Department of Engineering at the Federal University of Lavras, in Lavras, state of Minas Gerais - MG, Brazil. Twenty-two (22) LEPA Quad-Spray emitter nozzles were evaluated, with nozzle diameter ranging from 1.59 to 9.92 mm. The experimental design used was entirely randomized, with three replications.Increasing values of nozzle flow rate ranging from 77.44 up to 3,044 L h-1, were obtained with increasing nozzle diameter sizes. Application pattern width ranged from 0.56 up to 3.24m, according to nozzles diameter size. Low values of CDU (maximum of 35.73%) were observed when using the Quad-Spray nozzles. Observed average water application rates covered the range between 68.05 mm h-1 (the lowest value that was obtained with the 2.38mm nozzle) and 258.15 mm h-1 (the highest value that was observed with the 9.92 mm). Average water application rates increased in a simple non-linear function with the increase of nozzle size diameter. However, the weighted average increase in the amount of soil loss by erosion was not related to the increase of weighted average water application values.

Management zones definition using soil chemical and physical attributes in a soybean area

Several equipments and methodologies have been developed to make available precision agriculture, especially considering the high cost of its implantation and sampling. An interesting possibility is to define management zones aim at dividing producing areas in smaller management zones that could be treated differently, serving as a source of recommendation and analysis. Thus, this trial used physical and chemical properties of soil and yield aiming at the generation of management zones in order to identify whether they can be used as recommendation and analysis. Management zones were generated by the Fuzzy C-Means algorithm and their evaluation was performed by calculating the reduction of variance and performing means tests. The division of the area into two management zones was considered appropriate for the present distinct averages of most soil properties and yield. The used methodology allowed the generation of management zones that can serve as source of recommendation and soil analysis; despite the relative efficiency has shown a reduced variance for all attributes in divisions in the three sub-regions, the ANOVA did not show significative differences among the management zones.

Chemical attributes of soil and dry mass accumulation of maize fertilized with cassava wastewater

The aim of this study was to evaluate chemical attributes alterations of a clay-loam textured soil and dry mass accumulation of maize submitted to application of cassava wastewater doses in three assessment periods. The experiment was conducted under greenhouse using a completely randomized experimental design in a factorial 5 × 3, with four replicates. The analyzed factors of research were doses of cassava wastewater (0; 12.6; 25.2; 50.4; 75.6 m3 ha-1) andassessment periods (20, 40 and 52 days after germination). The following parameters were determined: electric conductivity of soil saturation extract, pH in water, content of available P, content of exchangeable K+, Ca2+, Mg2+ and Na+of soil, dry mass of leaves and stem. The application of cassava wastewater on soil enables increase of pH, electric conductivity of saturation extract, contents of available P, contents of exchangeable K+ and Na+ and dry mass of leaves and stem. However, only pH and content of exchangeable K+ of soil, the electric conductivity of saturation extract and dry mass of leaves and stem are influenced by assessment period.

Chemical characteristics of pequi fruits (Caryocar brasiliense Camb.) native of three municipalities in the State of Goiás - Brazil

In order to assure that the use of cerrado fruits occur in a sustainable way, studies to investigate their characteristics are extremely relevant. In this context, the present study aims to describe some chemical parameters of pequi fruits picked in three municipalities in southwestern Goiás State (Jataí, Rio Verde, and Serranópolis). In each city, two populations of pequi trees - pequizeiros, denominated areas, were selected. In each area, eight trees were selected for the fruit to be picked. The contents of phosphorus, potassium, calcium, magnesium, nitrogen, zinc, and ether extract were determined in the samples. The results demonstrate differences between the chemical characteristics studied for the fruits picked in different areas, which does not seem to vary in a significant way. Comparing the contents obtained in the present study with those required as human daily supply, further studies are recommended aiming at using the pequi fruit as a complementary alternative source of magnesium, manganese, and copper.

Foresight of physical-chemical characteristics of apple juice blends appointed to sparkling drink elaboration

The purpose of this research was to combine the use of the component blend design to the response surface methodology, in order to foresee the effect of ternary apple juice blends (Catarina, Granny Smith and Pink Lady cultivars) on the physical-chemical characteristics of musts appointed to sparkling drink elaboration. Twelve mixes were made (three individual samples, three binary mixes and six ternary mixes), analyzed on the content of total reducing sugars, total titratable acidity and phenolic compounds; and adjusted, respectively, to the linear, quadratic and special cubic models. The results were organized in ternary charts of surface response and, from the overlap of these charts, it was determined a viable region which delimited the range of apple juice compositions that make musts physically and chemically suitable to sparkling drink elaboration. To represent the various possible combinations, the central point of the triangular area of the viable region was calculated and, this point, which represents the proportions of 23.22% of Catarina, 66.23% of Granny Smith and 10.55% of Pink Lady cultivars, was chosen to constitute the formulation of the must to be used in the elaboration of apple sparkling drinks.

Chemical and sensory characteristics of pulp and peel 'cajá-manga' (Spondias cytherea Sonn.) jelly

Cajá-manga (Spondias cytherea) is a fruit with intense aroma and a sweet sour taste, thus being very appreciated. Its peel, in spite of being more fibrous, is tender and many times consumed with the pulp. The peel is a part of foods normally discarded, but many times, it is rich in taste and fibers, representing an option at the elaboration of new foods. Since there are no reports in the literature on the use of cajá-manga peel for jelly making, this work had the purpose of developing and evaluating this product. Based on the results, it was noted that the peels presented higher contents of protein, lipids, ashes, food fiber, total carbohydrates and pectin, and lower content of moisture, when compared to the pulp. The peel and the pulp (control) jellies presented the following physical-chemical characteristics: moisture, 29.5 and 34.2%; proteins, 0.19 and 0.27%; lipids, 0.11 and 0.16%; total sugars, 56.5 and 65.5%; and total soluble solids, 69 and 66 ºBrix, respectively. The sensory analysis indicated that the product elaborated from the peel presented satisfactory acceptance for all the assessed attributes: appearance, color, odor, texture, taste and global evaluation. It is concluded that the total substitution of the pulp by the peel in the formulation, results in a product with good nutritional value with no sensory damages.

Chemical and physicochemical characteristics changes during passion fruit juice processing

Passion fruit is widely consumed due to its pleasant flavour and aroma acidity, and it is considered very important a source of minerals and vitamins. It is used in many products such as ice-cream, mousses and, especially, juices. However, the processing of passion fruit juice may modify the composition and biodisponibility of the bioactive compounds. Investigations of the effects of processing on nutritional components in tropical juices are scarce. Frequently, only losses of vitamin C are evaluated. The objective of this paper is to investigate how some operations of passion fruit juice processing (formulation/homogeneization/thermal treatment) affect this product's chemical and physicochemical characteristics. The results showed that the chemical and physicochemical characteristics are little affected by the processing although a reduction in vitamin C contents and anthocyanin, large quantities of carotenoids was verified even after the pasteurization stage.