Ricardo Vejarano

Effect of Saccharomyces strains on the quality of red wines aged on lees

Ageing on lees involves ageing the wine in contact with yeast cells after fermentation. If combined with the addition of oak chips, it can soften the wood flavour and increase the aromatic complexity of wine. The aim of the present work is to optimise both ageing techniques through selection of an adequate Saccharomyces cerevisiae strain. The study lasted 6 months and content of polysaccharides, anthocyanins, proanthocyanidins, volatile compounds, colour parameters and sensory analysis, were periodically evaluated. Among the strains tested, G37 showed the highest release of polysaccharides (24.4±5.5 mg l(-1)). Vanillin, syringaldehyde and furfuryl alcohol increased with ageing time in 7VA2 treatment. The wine aged with CTPL14 strain presented fewer monomeric and oligomeric proanthocyanidins (12.4±0.6 and 83.4±8.3 mg l(-1), respectively), and showed the lowest astringency and bitterness sensations. Results show an improvement in the sensory profile of the red wine aged with a combination of these two techniques.

Evaluation of Food Quality and Safety with Hyperspectral Imaging (HSI)

The current lifestyle and a greater awareness of the benefits of proper nutrition demand requirements for products offered in the market, being very important the safety, sensory attributes and composition of these respect to the benefits from their constituents, which in most of cases can only be assessed using techniques that require high investment of human, technological and time resources. This has caused the food industry to seek to develop products, besides the aforementioned requirements, which use technologies with less product loss during the analysis. Of all the available options, hyperspectral imaging technology is shown as one of the most promising alternatives, being a nondestructive analysis technology that can easily engage in productive processes. In this review, we collect the most important studies conducted using the hyperspectral imaging technology in assessing the quality and safety of food products, such as fruits and vegetables, legumes, cereals, meats, dairy and egg products.

Reduction of 4-ethylphenol production in red wines using HCDC+ yeasts and cinnamyl esterases.

Hydroxycinnamate decarboxylase (HCDC) activity has been evaluated in several commercial yeast strains. The combined effect of using cinnamyl esterases (CE) and HCDC+ Saccharomyces cerevisiae strains has been studied in the formation of vinylphenolic pyranoanthocyanins (VPAs) during fermentation, analysing the kind and concentration of pigments formed according to the yeast strain used. Wines fermented with yeasts HCDC+ were contaminated with Dekkera bruxellensis and afterwards analysed to evaluate the formation of ethylphenols (EPs). The musts treated with CE and later fermented with HCDC+ yeast strains showed lower contents of 4-ethylphenol than those fermented with HCDC- strains. This reduction in the EP content is due to the transformation of hydroxycinnamic acids in stable VPAs pigments. The associated use of CEs and HCDC+ Saccharomyces strains is a natural strategy to reduce the formation of EPs in wines contaminated by Dekkera/Brettanomyces.

Evaluation of biological contaminants in foods by hyperspectral imaging (HSI): A review

ABSTRACT Responding to the ever-growing concern about safe foods and security, the food industries are forced to seek an emerging technology capable of detecting and quantifying contaminations, especially those of biological origin. Among the different emerging technologies, hyperspectral imaging is considered a good alternative as it can be easily applied at all steps of the food production process and is a non-destructive technique. This paper reviews targeted analytical applications of hyperspectral imaging in monitoring biological contaminants in food. First, traditional techniques for detection of biological contaminants in foods are presented, where disadvantages for practical applications are highlighted and explained in detail. Second, prominent applications of hyperspectral imaging from the last decade to food safety and quality assessment are reviewed, specifically focusing on both deteriorative and pathogenic microorganisms, microbial toxins, and parasites; whether acting individually or collectively in spoiling food products and/or represent a health risk to the consumers. Finally, relevant current and future challenges, advantages and disadvantages of hyperspectral imaging applications are briefly examined.

Theoretical considerations about usage of metabolic inhibitors as possible alternative to reduce alcohol content of wines from hot areas

The present review describes a number of metabolic inhibitors capable of redirecting the glycolytic pathway in winemaking yeasts of the species Saccharomyces cerevisiae, leading to an increase in yeast biomass production and the excretion of secondary metabolites alongside a desired reduction in wine alcohol content. The main application of these inhibitory molecules lies in the preparation of reduced-alcohol wines from grapes grown in hot areas.

Adsorbent material based on passion-fruit wastes to remove lead (Pb), chromium (Cr) and copper (Cu) from metal-contaminated waters

The aim of the present work was to evaluate the feasibility of passion-fruit shell (PFS) biomass as adsorbent material to remove heavy metals from contaminated waters. Model mediums were used, which were composed of distilled water and the respective metal: lead (Pb), chromium (Cr) and copper (Cu), with a dose of 10g of dry PFSbiomass per liter of medium. The residual concentration of each metal was determined by Atomic Absorption Spectrophotometry (AAS). A good adsorption capacity was exhibited by this agro industrial waste, achieving removal levels of 96,93 and 82% for Pb, Cr and Cu, respectively. In addition, the results obtained showed an adequate fit to the Freundlich model (R2 > 0.91), on the basis of which, the following values of adsorption capacity (k: 1.7057, 0.6784, 0.3302) and adsorption intensity (n: 0.6869, 2.3474, 1.0499), for Pb, Cr and Cu respectively, were obtained. Our results suggest that Pb, Cr and Cu ions can be removed by more than 80% by using this agro industrial waste, which with...

Improved of the colorimetric parameters in cranberry (Vaccinium corymbosum) wine by chaptalization

Consuming foods rich in anthocyanins like blueberry (Vaccinium corymbosum), can help prevent various diseases due to its antioxidant and anti-inflammatory capacity. Being a perishable fruit and no significant exportable surpluses, an alternative use and consumption would be by making wine. However, low sugar content can limit vinification, having to supplement it with exogenous sugars, known as chaptalization procedure, which also can improve the extraction of anthocyanins due to its high solubility in ethanol. The aim of this study was to evaluate the effect of chaptalization on the colorimetric parameters of blueberry wine. Blueberry juice (10 °Brix, must control) was supplemented with grapemust and sucrose to reach 17 °Brix (must AUS). After fermentation the alcohol content was determined, besides, the color intensity (CI) and hue were compared with a commercial red wine. Chaptalization allowed to increase the alcohol content of 6.25 to 10.10% v / v, and greatly improve the extraction of anthocyanins, with IC and hue values of 5.11 and 5.70, and 0.78 and 0.83 for control and AUS wines, respectively; AUS even approaching the commercial red wine used as a reference (CI: 5.98, hue: 0.83). Whereupon, the extraction of anthocyanins in blueberry wine is improved, thus being able to reap the benefits of these pigments in the prevention of various diseases