Flint glass bottles cause white wine aroma identity degradation

Impact of light on protective fractions of Cu in white wine: Influence of oxygen and bottle colour

Cu(II)-organic acid (fraction I) and Cu(I)-thiol (fraction II) complexes can suppress sulfhydryl off-aromas in wine. This study investigated the impact of light exposure on the protective fractions of Cu of bottled white wine. Fluorescent light-exposed Chardonnay with two initial concentrations of dissolved oxygen (0.5 and 10 mg/L) was stored in different coloured bottles and concentrations of Cu fractions and riboflavin, a photo-initiator at 370-440 nm, were measured during 110 days storage. Light-exposed wines with lower oxygen concentrations resulted in a 100-fold decrease in the Cu fraction I half-life, and a 60-fold decrease for Cu fractions I and II combined. The half-life for Cu fraction I decay during light exposure was extended 30-fold with the use of brown compared to flint glass. Light exposure can rapidly exhaust the protective Cu fractions in wine, and bottles with less light transmission below 440 nm can slow this loss.

The Addition of Glutamine Enhances the Quality of Huangjiu by Modifying the Assembly and Metabolic Activities of Microorganisms during the Fermentation Process

In this study, the effects of adding glutamate (Glu), glutamine (Gln), aspartate (Asp), and asparagine (Asn) on the flavor formation of Huangjiu were investigated, and the effect of Gln concentration on the quality, microbial community structure, and flavor development of Huangjiu was further explored. Varied Gln concentrations influenced yeast growth, sugar utilization, microbial communities, and quality attributes. Additional Gln promoted yeast cell counts and sugar depletion. It increased the complexity of bacterial co-occurrence networks and reduced the impact of stochastic processes on assembly. Correlation analysis linked microorganisms to flavor compounds. Isolation experiments verified the role of Saccharomyces cerevisiae, Aspergillus chevalieri, Bacillus altitudinis, and Lactobacillus coryniformis in flavor production under Gln conditions. This research elucidated the microbiological mechanisms by which amino acid supplementation, especially Gln, enhances Huangjiu quality by modulating microbial metabolic functions and community dynamics during fermentation. This research is significant for guiding the production of Huangjiu and enhancing its quality.

Evaluating the Atypical Aging Potential Development in Sparkling Wines Can Be Achieved by Assessing the Base Wines at the End of the Alcoholic Fermentation

Traditional sparkling wine production is a lengthy and costly process, involving a double fermentation step and a period of aging sur lie; thus, monitoring quality during the key manufacturing stages is crucial. The effects of the second fermentation on the development of 2-aminoacetophenone (AAP), the main marker of the atypical aging (ATA) defect, were investigated on 55 base wines (BWs) and corresponding sparkling wines (SWs) produced in an experimental winery. While the AAP content of the SWs was observed to be higher than the BWs, it was found that an artificial aging test carried out on the BWs could be a good predictor of ATA development in SWs. Further, the antioxidant capacity of the SWs was noticed to correlate well with the potential AAP formed during accelerated aging. Finally, an analysis of covariance (ANCOVA) model of linearization capable of predicting AAP formation in SWs using the data obtained from the corresponding BWs was created.

A key to wine conservation lies in the glass-cork interface

This study investigates the evolution of the oxygen barrier properties of the bottleneck-stopper system under conditions simulating the conservation of wine in the bottle (presence of model wine, storage position, and temperature) over a long aging period of 24 months. The results highlighted that the oxygen diffusion coefficient of the stopper alone is not modified regardless of the storage conditions. At 20°C, the presence of model wine favors oxygen transfer at the glass-cork interface, accounting for nearly 75% of total oxygen transfer in comparison to cork studied without model wine. Yet, the position of the bottle during storage, vertical (i.e. cork in contact with the vapor phase of the model wine) or horizontal (i.e. cork in contact with the liquid phase), does not influence the oxygen transfer. At higher storage temperatures (35 and 50°C), the barrier properties of the bottleneck-cork system remain stable up to 9 and 3 months, respectively. After this period, an alteration of the barrier properties is observed with an increase of the transfer at the glass-cork interface.

Impact of meteorological conditions, canopy shading and leaf removal on yield, must quality, and norisoprenoid compounds content in Franciacorta sparkling wine

Climate change is a major concern in agriculture; in grapevine production, climate change can affect yield and wine quality as they depend on the complex interactions between weather, plant material, and viticultural techniques. Wine characteristics are strongly influenced by microclimate of the canopy affecting primary and secondary metabolites of the grapevine. Air temperature and water availability can influence sugar and acid concentration in grapes and relative wines, and their content of volatile compounds such as norisoprenoids. This becomes relevant in sparkling wine production where grapes are generally harvested at a relatively low pH, high acidity, and low sugar content and where the norisoprenoids significantly contributes to the final aroma of the wine. The effect of climate change on grapevine and wine, therefore, calls for the implementation of on-field adaptation strategies. Among them canopy management through leaf removal and shading have been largely investigated in the wine growing sector. The present study, conducted over 4 years (2010-2013) aims at investigating how leaf removal and artificial shading strategies affect grape maturation, must quality and the production of norisoprenoids, analyzed using an untargeted approach, in sparkling wine. Specifically, this paper investigates the effect of meteorological conditions (i.e., water availability and temperatures) and the effect of leaf removal and shading on Vitis vinifera L. cv. Chardonnay and Pinot noir, which are suitable to produce sparkling wine in the DOCG Franciacorta wine growing area (Lombardy, Italy). The effect of leaf removal and shading practices on norisoprenoids has been the focus of the study. No defoliation and artificial shading treatments play an important role in the preservation of the acidity in warm seasons and this suggests calibrating defoliation activities in relation to the meteorological trend without standardized procedures. This is particularly relevant in the case of sparkling wine, where the acidity is essential to determine wine quality. The enhanced norisoprenoid aromas obtained with a total defoliation represent a further element to direct defoliation and shading strategies. The obtained results increase knowledge about the effect of different defoliation and artificial shading applications in relation to meteorological condition supporting the management decision-making in the Franciacorta wine growing area.

Effects and impacts of technical processing units on the nutrients and functional components of fruit and vegetable juice

Fruit and vegetable juice (FVJ) has become a favorite beverage for all age groups because of its excellent sensory and nutritional qualities. FVJ has a series of health benefits such as antioxidant, anti-obesity, anti-inflammatory, anti-microbial and anti-cancer. Except for raw materials selection, processing technology and packaging and storage also play a vital role in the nutrition and functional components of FVJ. This review systematically reviews the important research results on the relationship between FVJ processing and its nutrition and function in the past 10 years. Based on the brief elucidation of the nutrition and health benefits of FVJ and the unit operation involved in the production process, the influence of a series of key technology units, including pretreatment, clarification, homogenization, concentration, sterilization, drying, fermentation and packaging and storage, on the nutritional function of FVJ was systematically expounded. This contribution provides an update on the impacts of technical processing units on the nutrients and functional components of FVJ and new perspectives for future studies.

The Riboflavin Metabolism in Four Saccharomyces cerevisiae Wine Strains: Assessment in Oenological Condition and Potential Implications with the Light-Struck Taste

Riboflavin (RF), or vitamin B2, is an essential compound for yeast growth and a precursor of the flavin coenzymes, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), involved in redox and non-redox processes. RF is a photosensitive compound involved in the light-struck taste (LST), a fault causing the formation of off-flavors that can develop when the wine is exposed to light in the presence of methionine (Met), as well. As both RF and Met can be associated with detrimental changes in wines, a better comprehension of its yeast-mediated production is relevant to predict the maintenance of the desired character of the wine. This study aims at assessing the production of flavin derivatives (FDs) and Met by S. cerevisiae oenological starters under laboratory conditions. The results showed the presence of extra- and intracellular FDs, and Met is a strain-dependent characteristic being also affected by the initial content of RF in the medium. This finding was confirmed when the winemaking was carried out in a relevant environment. Our results evidenced the important impact of the yeast strain on the content of RF and its derivatives.