Chemical Characterization of Sauvignon Blanc Wines from Three Cold-Climate-Growing Areas of Chile.

The influence of the geographical location on the chemical composition of commercial Sauvignon Blanc wines was investigated. The assay was carried out on Sauvignon Blanc wines from three cold-climate valleys in Central Chile, Casablanca, Leyda, and San Antonio. The analyses revealed clear variations in some chemical parameters, especially in titratable acidity, which was higher in the geographical areas closest to the Pacific Ocean, such as the Leyda and San Antonio valleys. Regarding the composition of low-molecular-weight phenolic compounds, 17 compounds were found, and the results show that the Casablanca valley exhibits a greater abundance of monomeric flavanols, such as (+)-catechin, whereas the Leyda valley shows a higher abundance in flavonols and phenolic acids esterified with tartaric acid. Concerning the aromatic compound profile, the wines from the Casablanca valley showed a greater abundance of esters, C13 norisoprenoids, and some terpenes. The PLS-DA analysis revealed some differences, especially between wines from Casablanca and Leyda, demonstrating that the difference in the chemical composition of the wines was influenced by the geographical area.

Antarctic Soil Yeasts with Fermentative Capacity and Potential for the Wine Industry.

Low fermentation temperatures are usually employed to obtain high-quality wines. This is especially interesting for white wine production since it prevents the loss of volatile compounds and a browning appearance; however, available fermentative yeasts do not usually tolerate low temperatures. Therefore, an interesting place to find new yeasts with cryotolerance is the Antarctic continent. From soil samples collected in Antarctica, 125 yeasts were isolated, of which 25 exhibited fermentative activity at 10 °C. After a fingerprinting assay, we classified the candidates into nine isotypes and sequenced internal transcribed spacer regions for their identification. These yeasts were identified as part of the Mrakia genus. Sugar and alcohol tolerance tests showed that some of these Antarctic soil yeasts were able to grow up to 9% alcohol, and 25% sugar was reached; however, they exhibited longer latency periods compared to the control Saccharomyces cerevisiae. The optimal growing temperature for the isolated Antarctic yeasts was between 10 °C and 15 °C. A comprehensive analysis of the results obtained showed that the isolates 10M3-1, 4M3-6, and 4B1-35 could be good candidates for fermentation purposes due to their alcohol, sugar tolerance, and growth features. Our results prove that it is possible to isolate fermentative yeasts from Antarctic soil with promising characteristics for their potential use in the wine production industry.

Phenolic, Polysaccharides Composition, and Texture Properties during Ripening and Storage Time of New Table Grape Cultivars in Chile.

The aim of this study is to determine the phenolic and polysaccharidic composition, texture properties, and gene expression of new seedless table grape cultivars Timco™ and Krissy™ and compare them to the traditional table grape variety Crimson Seedless (Vitis vinifera L.), during ripening and in commercial postharvest conditions. According to the results, phenolic compounds were present in very different proportions. The total anthocyanins responsible for skin color increased during maturation and the majority anthocyanin in the three cultivars was peonidin-3-glucoside, followed by malvidin-3-glucoside. The phenolic compounds presented a different behavior (decreasing or increasing) during postharvest. The total skin soluble polysaccharides decreased during ripening and postharvest in Crimson Seedless and Krissy™ and remained constant from technological maturity to postharvest storage in Timco™. In all cultivars, the majority soluble polysaccharide fraction was that with a molecular mass between 500 and 35 KDa. The skin mechanical properties of table grapes were good parameters for differentiating varieties, with better results for the new cultivars, compared to the traditional Crimson Seedless, especially in postharvest. Genes involved in the flavonoid pathway and cell wall metabolism in skins exhibited an increase in expression from veraison to remaining constant at the end of the berry ripening.

Combined effects of the vessel type and bottle closure during Chilean Sauvignon Blanc wine storage over its volatile profile.

A Sauvignon Blanc wine was subjected to a maturation period of six months by using four different types of vessels in triplicate: cylindrical stainless steel tanks, oval-shaped polyethylene tanks, cubic-shaped polyethylene tanks, and clay jars. After maturation in the different vessels, wines were bottled using three different closures (natural cork, synthetic cork, and screwcaps). The volatile compound profiles of the wine samples were recorded by SPME-GC-MS throughout vessel maturation as well as after the bottle storage period. In general terms, wines stored in stainless steel tanks showed the highest contents of volatile compounds when compared with the other tested vessels. Moreover, wines from bottles capped with screwcaps showed the highest contents of most of the volatile compounds when compared with the other closures. Moreover, an interaction between the vessel and the closure was observed: when screwcaps were used during bottle aging, the resulting wines were very similar to those matured in stainless steel vessels. These results suggest that the use of screwcaps hides the differences originating from wine composition during maturation in vessels other than stainless steel.

Combined effects of sulfur dioxide, glutathione and light exposure on the conservation of bottled Sauvignon blanc.

Oxygen exposure may trigger a series of changes that could be detrimental to the quality white wines. This study evaluated the combined effects of sulfur dioxide, glutathione and light exposure on the chemistry and sensory perception of bottled Sauvignon blanc. The wines were manually bottled into clear bottles, closed with low oxygen transfer rate stoppers, and stored for three months, either exposed or protected from light. The wines exposed to artificial light showed higher rates of sulfite loss and oxygen consumption, were significantly darker in color, exhibited significant changes in the concentration of phenolics and volatile compounds, were perceived as less fruity/floral, and had higher nuances of solvent, earthy and honey aromas than the ones protected from light. The treatments with higher amounts of initial sulfites and glutathione were able to delay some of these changes but were less significant than protecting the wines from artificial light.

Chemical and Physical Implications of the Use of Alternative Vessels to Oak Barrels during the Production of White Wines.

Recently, the use of alternative vessels to oak barrels during winemaking has become increasingly popular, but little is known about their impact on the chemical composition of the resulting wines. To address this issue, a Sauvignon Blanc wine was elaborated from the same grape juice by using cylindrical stainless-steel tanks, oval-shaped concrete vessels, oval-shaped polyethylene vessels, and clay jars in triplicate. Each vessel was used for alcoholic fermentation and the aging of wines over its own lees. Wines elaborated in concrete vessels showed the highest pH and the lowest titratable acidity, most likely related to the observed release of inorganic compounds from the concrete walls. Little effect of the vessels was seen on the wine color and phenolic composition. Wines elaborated in clay jars showed the highest turbidity and the highest content of soluble polysaccharides, while those made using cylindrical stainless-steel tanks showed the highest content of volatile compounds. Despite the observed differences, all of the vessels tested seem suitable for white wine production since every wine showed chemical features that corresponded with the quality standards of Sauvignon Blanc wines.

Ripening and Storage Time Effects on the Aromatic Profile of New Table Grape Cultivars in Chile.

The aim of this study was to determine the volatile profiles of new seedless table grape cultivars Timco™, Magenta™, Krissy™ and Arra15™ and compare them with the traditional table grape variety Crimson seedless. The volatile profiles were extracted employing solid-phase microextraction and analyzed with gas chromatography coupled with mass spectrometry. Terpenes were present in very different proportions, with the Magenta, Krissy, and Arra15 varieties showing much higher quantities than Crimson and Timco. ß-Ionone and octanal, important indicators in the aromatic flavor quality of table grapes, were present in higher levels in Crimson and Arra15, and this might be responsible for driving consumer preference. These compounds significantly increased during ripening, except in Crimson, and gradually decreased from harvest to the end of the storage in all the cultivars. Evolution during ripening was different depending on the variety but the general tendency terpenes was to increase from veraison to harvest. A postharvest study revealed that Crimson could have a better conservation of the volatile components during postharvest storage compared with Timco and Krissy. These results could help in plant breeding programs and to make decisions for new planting according to needs for storing fresh table grapes given distances to consumer markets.

Impact of berry size at harvest on red wine composition: a winemaker's approach.

BACKGROUND: A classical postulate of viticulture declares that small grape berries produce the best red wines. The popularity of this postulate among winemakers leads them to consider berry size at harvest as a tool to measure the grape's potential to obtain great red wines. To address this issue, two vineyards from the same cultivar and subjected to the same physiological conditions during growing were selected for their difference in average grape berry size at harvest. Grapes from both origins were characterized and used for red winemaking by the same way. Release of volatile compounds and phenolic compounds during the alcoholic fermentation was monitored, and the finished wines were chemically characterized. RESULTS: Larger grapes have a lower theoretical surface-to-volume ratio but have thicker skins and a greater proportion of skins (m/m). Wines made from grapes with a greater proportion of skins contain higher amounts of phenolic compounds, terpenes, volatile acids, acetate esters and polysaccharides. CONCLUSION: According to the results, it seems that grape skin extraction is more related to skin proportion than to berry size. Thus not always smaller grapes produce darker red wines. © 2019 Society of Chemical Industry.

Impact of closure type and storage temperature on chemical and sensory composition of Malbec wines (Mendoza, Argentina) during aging in bottle.

Malbec is the flagship variety of Argentina mainly due to its high oenological value and plasticity to obtain different wine styles. During bottled aging, the chemical and organoleptic composition of wines is subject to changes depending on the aging conditions (closure, oxygen level, temperature, time). However, the combined effect of these factors on chemical composition and organoleptic characteristics of Malbec wines has not been studied yet. Wines were bottled with screw cap and natural cork and were kept in chambers at 15 °C and 25 °C for 2 years. Sampling was performed at 2, 4, 6, 9, 12, 15, 18, 21 and 24 months. Concentrations of free sulfur dioxide, dissolved oxygen, anthocyanins, tannins, esters, volatile phenols, organic acids, and color saturation decreased during the storage process. While, the formation of polymeric pigments, the color attributes (lightness and hue) and the levels of alcohols, norisoprenoids, furanoids and terpenoids increased. At 24 months, Malbec wines were organoleptically different. Wines kept at 15 °C were associated with high sensory perceptions in color intensity and violet tint, those presented a positive correlation with free sulfur dioxide, tannins, and anthocyanins levels. On the contrary, wines aged at 25 °C were linked with high sensory perceptions of dried vegetative and dried fruit aromas. These descriptors were positively correlated with norisoprenoids, furanoids, and terpenoids. In general, the chemical composition and organoleptic attributes of bottled Malbec wines (Mendoza, Argentina) were stable respect closure type employed, but highly sensitive to the combined effect of time and storage temperature. This finding is key to making decisions about the wine style searched, and costs (e.g. refrigeration) involved in the conservation period until consumption.

Correction: Del Barrio-Galán, R., et al. Evaluation of Yeast Derivative Products Developed as an Alternative to Lees: The Effect on the Polysaccharide, Phenolic and Volatile Content, and Colour and Astringency of Red Wines. Molecules 2019, 24, 1478.

The authors wish to make the following corrections to this paper [...].

Evaluation of Yeast Derivative Products Developed as an Alternative to Lees: The Effect on the Polysaccharide, Phenolic and Volatile Content, and Colour and Astringency of Red Wines.

Due to the increase of the use of yeast derivatives (YDs) in winemaking to improve the technological and sensory properties in wines, in this work we evaluated the effect of the post-fermentation application of different yeast derivative products on the physical and chemical properties and astringency of red wines during two consecutive harvests. A commercial and two experimental new yeast derivatives were applied at a medium‒high dosage (30 g/hL). The addition of different yeast derivatives in red wine increased the concentration of different polysaccharide fractions and, therefore, the total polysaccharide content, producing a decrease in the duration of the wine astringency perception over time. The use of yeast derivatives could produce an adsorption/clarification and/or protective effect on the phenolic compounds. However, it did not produce an important modification of the colour parameters. An intensification or a lower decrease of the most volatile compound groups was produced, but it depended on the YDs and yeast strain used in fermentation and post-fermentation processes.

Water stress and ripeness effects on the volatile composition of Cabernet Sauvignon wines.

BACKGROUND: Controlled water deficits affect grape berry physiology and the resulting wines, with volatile composition being the one of the affected parameters. However, there is a potential disconnect between aromatic maturity and sugar accumulation. Accordingly, the effects of three different water status levels over two growing seasons (2014 and 2015) and two different harvest dates on the aroma compounds from Cabernet Sauvignon wines were studied. Volatile compounds were determined using headspace solid phase microextraction coupled with gas chromatoghraphy/mass spectrometry. RESULTS: Around 45 volatile compounds were determined in the wines and, among these, esters were affected the most, presenting lower concentrations when the most restrictive water treatment was applied in both years. By contrast, volatile acids presented the highest concentrations when the lowest level of irrigation was applied. On the other hand, a delay in harvesting produced an increase in the total amount of volatile compounds in samples from the most restrictive water treatment. These results are coincident with a principal component analysis that indicated a great separation between years, deficit irrigation treatments and harvest dates. CONCLUSION: The results of the present study suggest that a low water supply had a negative effect on the aromatic potential of wines at a similar ripening stage. However, this effect could be countered by harvesting at a later date. © 2017 Society of Chemical Industry.

Evaluación de menús ofertados em comedores escolares: comparación entre colegios públicos, privados y concertados / Evaluation of school menus: comparing public, private and charter schools

RESUMEN Objetivo: Evaluar los menús ofertados en los colegios públicos, privados y concertados de la ciudad de Sevilla (España) para los diferentes grupos de edad escolar. Métodos: Se consideró un total de 86 colegios, incluyendo centros públicos, privados y concertados, representando a todos los distritos de la ciudad. Cuatro colegios disponían de cocina propia, mientras el resto tenían contratado un catering. Los menús iban dirigidos a escolares de entre 3 a 16 años. Se evaluó el grado de cumplimiento de las recomendaciones respecto a la frecuencia mensual de los distintos grupos de alimentos, repetición de recetas, variabilidad de técnicas culinarias y equilibrio nutricional. Para el tratamiento estadístico se utilizó el programa Statistica 7. Resultados: En la mayoría de comedores escolares la oferta de frutas, verduras y legumbres era deficitaria a diferencia de los postres lácteos, carnes y patatas. Se observaron diferencias significativas entre los tres tipos de colegio respecto a la frecuencia mensual de alimentos, siendo los públicos los que más se ajustaban a las recomendaciones. La mayoría de los comedores evaluados no aportaban menús suficientemente detallados así como se observó falta de variedad de técnicas culinarias. La energía no se ajustaba a las necesidades de todos los grupos de edad y la distribución de macronutrientes sólo era adecuada en el 50% de los menús. Conclusión: Aunque se ha observado una evolución favorable de los menús respecto a estudios anteriores hay que seguir trabajando en aumentar la oferta de frutas y verduras, disminuir el aporte de lípidos y proteínas, así como adaptar la energía de los menús a los diferentes grupos de edad.

ABSTRACT Objective: To evaluate menus offered in public, private and charter schools in the city of Seville (Spain) for different groups of school children. Methods: A total of 86 schools were evaluated, including public, private and charter schools, which represented every district of the city. Four schools possessed their own kitchen, while the others had hired a catering service. The menus were aimed at school children aged between 3 and 16 years. The adequacy of menus regarding the monthly frequency of the different food groups, recipe repetition, variability of cooking techniques and nutritional balance were evaluated according to the recommendations. Statistica 7 software was used for statistical analysis. Results: In most school cafeterias fruits, vegetables and legumes supply was defincient compared to dairy desserts, meats and potatoes. Significant differences regarding the monthly food frequency were observed between the three types of school, being the public schools the ones the most followed the recommendations. Most school cafeterias evaluated did not provide sufficiently detailed menus and a lack of variety of culinary techniques was observed.The calories offered did not meet the needs of all age groups and macronutrient distribution was only adequate in 50% of the evaluated menus. Conclusion: Although there has been a favourable evolution of menus from previous studies, further work is needed to increase the offer of fruits and vegetables, to reduce the intake from lipids and protein, as well as to adapt the calories of the menus to the different age groups.

A comparative study on aromatic profiles of strawberry vinegars obtained using different conditions in the production process.

Impact odorants in strawberry vinegars produced in different containers (glass, oak and cherry barrels) were determined by gas chromatography-olfactometry using modified frequency (MF) technique, and dynamic headspace gas chromatography-mass spectrometry. Aromatic profile of vinegar from strawberry cooked must was also studied. All strawberry vinegars retained certain impact odorants from strawberries: 3-nonen-2-one, (E,E)-2,4-decadienal, guaiacol, nerolidol, pantolactone+furaneol, eugenol, γ-dodecalactone and phenylacetic acid. Isovaleric acid, pantolactone+furaneol, p-vinylguaiacol, phenylacetic acid and vanillin were the most important aroma-active compounds in all vinegars. The strawberry cooked must vinegar accounted for the highest number of impact odorants. Wood barrels provided more aroma complexity than glass containers. Impact odorants with grassy characteristics were predominant in vinegar from glass containers, and those with sweet and fruity characteristics in vinegars from wood barrels. Principal component analysis indicated that the production process led to differences in the impact odorants.