GIRVITEN - Artículos de Revista

Impact of glucose oxidase treatment in high sugar and pH musts on volatile composition of white wines

2023-01-01T00:00:00Z

Climate change is modifying the composition of the grapes, increasing sugar and pH levels, which produces unbalanced wines with high alcohol degree, low acidity and poor aromatic notes. In this study, glucose oxidase (GOX) and catalase (CAT) were applied in white must with high sugar content and pH (>3.8) to simultaneously decrease glucose concentration and pH. The effect of enzyme treatment on volatile composition of wine was investigated. A concentration of 0.17 mkat/L for both GOX and CAT was sufficient to produce a remarkable reduction of glucose concentration in the must (61.5 g/L), achieving similar results within the pH range of 3–4. The musts subjected to enzymatic treatment yielded more balanced wines, lowering their alcohol content by 10–27 mL/L and pH by 0.3–0.5, while leaving their chromatic characteristics unchanged compared to the control wines. As positive effects, enzyme treatment reduced the concentrations of C6-alcohols with green-herbaceous notes and high-chain ethyl esters with soapy notes in wines, and did not modify the concentrations of short-chain ethyl esters, acids and higher alcohols. However, the concentrations of heptyl acetate and 2-phenylethanol with floral notes, and some ketones with floral and fruit notes, were lower in wines from treated musts.

Influence of somatic cell count and breed on capillary electrophoretic protein profiles of ewes’ milk: A chemometric study

2007-01-01T00:00:00Z

Bulk tank ewe milk from the Assaf, Castellana, and Churra breeds categorized into 3 somatic cell count (SCC) groups (<500,000; 1,000,000 to 1,500,000; and >2,500,000 cells/mL) was used to investigate changes in chemical composition and capillary electrophoresis protein profiles. The results obtained indicated that breed affected fat, protein, and total solids levels, and differences were also observed for the following milk proteins: β-, β1-, β2-, and αs1-III-casein, α-lactalbumin, and β-lactoglobulin. High SCC affected fat and protein contents and bacterial counts. The level of β1-, β2-, and αs1-I-casein, and α-lactalbumin were significantly lower in milk with SCC scores >2,500,000 cells/mL. A preliminary study of the chemical, microbiological, and electrophoretic data was performed by cluster analysis and principal components analysis. Applying discriminant analysis, it was possible to group the milk samples according to breed and level of SCC, obtaining a prediction of 100 and 97% of the samples, respectively.

Trasplante de remolacha mediante PAPER-POT

1999-01-01T00:00:00Z

Mediante la fotosíntesis, la remolacha azucarera transforma, a lo largo de su ciclo vegetativo, la energía luminosa captada por las hojas en los azúcares y otras sustancias que se van acumulando en la raiz. Para conseguir el máximo aprovechamiento y optar, por tanto, a una mayor producción y rendimiento en azúcar, es necesario: - Partir de una buena población de plantas, homogénea, con una densidad adecuada y en perfecto estado sanitario. - Alargar en lo posible el periodo de tiempo en que el cultivo permanece en el terreno, desde la nascencia de las plantas hasta la recolección. El trasplante de remolacha mediante el método del paper pot trata de conseguir estos objetivos. La técnica se basa en obtener en invernadero plantas fuertes y sanas, realizando la siembra en unos cartuchos de papel (paper-pot) que permiten mecanizar el trasplante, y cuyo material se descompone de forma natural en el campo. Fruto del alargamiento del ciclo de cultivo, tanto la producción por hectárea como la polarización de la remolacha trasplantada se ven incrementadas frente a la sembrada de forma tradicional. [Texto extraído del artículo de Pedro Martín Peña].

Prevención y tratamiento de la clorosis férrica del viñedo

2006-01-01T00:00:00Z

La clorosis férrica, o carencia nutricional de hierro, es una enfermedad que causa graves daños al viñedo y que es difícil y costosa de corregir. Esta deficiencia se da fundamentalmente en suelos muy calizos o con elevado pH, donde la disponibilidad del microelemento para las plantas es muy reducida. EI hierro interviene en la síntesis de clorofila y su carencia modifica la estructura y la funcionalidad del aparato fotosintético, pudiendo limitar gravemente la expresión vegetativa del viñedo en todos sus componentes: vigor, rendimiento y calidad de la uva.

Relationships between water status, leaf chlorophyll content and photosynthetic performance in Tempranillo vineyards

2016-01-01T00:00:00Z

The aims of this work were (i) to study the relationships between leaf water potential, foliar chlorophyllcontent and photosynthetic performance of grapevines under field conditions, and (ii) to evaluate thefeasibility of chlorophyll fluorescence parameters to assess water status in commercial vineyards. Duringthree consecutive seasons (2011 to 2013), 20 non-irrigated “Tempranillo” vineyard subzones were monitoredin Ribera del Duero, Spain. Data on foliar chlorophyll content, midday and predawn leaf water potential,net assimilation and chlorophyll fluorescence parameters were measured at fruit set, pre-véraison andvéraison. The results show that the water potential indicated weak to moderate stress in the study yearsand decreased along the vegetative cycle, while foliar chlorophyll contents showed an increasing trend. Thecorrelation between both variables was not consistent. Linear regression of the chlorophyll fluorescenceparameters in dark-adapted leaves, Fo, Fv and Fv/Fm, over chlorophyll content was strong in all thestudy years (higher determination coefficients for Fv/Fm at fruit set in 2012 and 2013). In general, thewater potential with low coefficients of variation showed a low effect on photosynthesis activity, althoughvalues in variables such as Fm, Fv, Fv/Fm, Fs/Fo and ΦPSII registered an increasing trend when middayleaf water potential decreased in the pre-véraison and véraison stages. These variables could be useful toestimate water status in commercial vineyards for application in precision viticulture.

Abscisic acid and ethephon treatments applied to ‘Verdejo’ white grapes affect the quality of wine in different ways

2018-01-01T00:00:00Z

Exogenous ethephon and abscisic acid (ABA) treatments are used worldwide to improve the coloring of red table grapes, but there is little information about their impact on the quality of white grapes and wines. The aim of this work was to evaluate the effects of exogenous ethephon and ABA applications at veraison on the composition of ‘Verdejo’ white grapes, and on the quality of their wines. To attain this objective, a field trial was carried out in a ‘Verdejo’/110 Richter vineyard located in north-central Spain. Two levels of ethephon (0 and 1500 mg L−1) and ABA (0 and 800 mg L−1) were sprayed on clusters at veraison, in a factorial design for three consecutive seasons. Ethephon and ABA had additive effects, decreasing titratable acidity and increasing pH of the must, which could be exploited by accelerating the grape ripening process in cold-climate zones. Nevertheless, each growth regulator affected the composition and sensory analysis of the wines differently. Ethephon treatments produced wines with lower concentration of acids and better flavor quality than those made from untreated plants, while wines with ABA applications tended to have a higher ethanol concentration and poorer aroma quality than controls. The wines submitted to treatments with ethephon obtained the best overall evaluation in the sensory analysis throughout the trial.

Aroma composition of Tempranillo grapes as affected by iron deficiency chlorosis and vine water status

2021-01-01T00:00:00Z

Water deficit and iron nutritional deficiency (iron chlorosis) are frequent environmental stresses affecting grapevine production in the Mediterranean region. The objectives of this work were (i) to study the combined effects of both stresses on aromatic profile of Tempranillo grapes, occurring simultaneously in the vineyard, and (ii) to evaluate the viability of foliar chlorophyll content at veraison (Chl) to early assess aromatic quality potential of grapes in those conditions. Twenty non-irrigated vineyard subzones (10 m × 10 m each), affected and non-affected by iron chlorosis, were monitored in Ribera del Duero Appellation of Origin (North-Central Spain) during two consecutive seasons. Factorial ANOVA was performed to study the effects of predawn leaf water potential and Chl measured at veraison on the must composition parameters and, specifically, on the concentrations of free and bound aromatic compounds. Water deficit tended to increase color intensity and extractable anthocyanin content of the grapes, whereas the incidence of iron deficiency enhanced total phenolic compound content within subzones with better water status. More water or iron stressed subzones restricted C6-alcohols contents than less stressed subzones. Without significant effects on vine vigor, yield or berry size, the incidence of iron chlorosis increased the concentrations of some specific terpenes, C13-norisoprenoids, volatile acids and volatile phenols. These results showed that low to moderate iron stress can have positive effects on grape aromatic quality, and demonstrated that Chl can be a useful tool in precision viticulture to map the aromatic potential within rainfed vineyards affected by iron chlorosis.