Effect of the high pressure treatments on the physicochemical properties of the young red wines supplemented with pyruvic acid

Effect of postharvest grape dehydration on chemical composition, antioxidant activity and sensory characeteristics of Marselan wines

To explore the effect of postharvest dehydration on grape berries and wine quality, we determined physicochemical properties, polyphenols, antioxidant activities, volatile compounds and sensory characteristics for wines brewed by 'Marselan' (Vitis vinifera L.) grapes with 0%, 10%, 15%, 20%, and 25% of water loss. The result showed that postharvest dehydration improved the alcohol content, residual sugar and titratable acidity of Marselan wine. Phenolic compounds and antioxidant activities in wines with a dehydration of 20% have significantly increased. Postharvest dehydration increased the contents of isobutanol, isoamyl alcohol, phenylethyl alcohol, ethyl acetate, isoamyl acetate and ethyl butyrate in Marselan wines, and enhanced the floral, fruity and sweet taste of wines. Marselan wine had the lowest acceptability score under the condition of severe dehydration (25% dehydration), which was related to the significant increase of tannins content. In summary, postharvest dehydration was beneficial in improving the quality of Marselan wine.

Enhancement of ester biosynthesis in blueberry wines through co-fermentation via cell-cell contact between Torulaspora delbrueckii and Saccharomyces cerevisiae

This study investigated the effects of co-fermentation of T. delbrueckii and S. cerevisiae on the volatile composition and sensory characteristics of blueberry wines. Mixed fermentation led to higher levels of terpenes, higher alcohols, and esters compared to wines fermented with each yeast individually. Conversely, when T. delbrueckii were physically separated from S. cerevisiae in the double-compartment fermenter, contrasting outcomes emerged. The stronger fruity aroma induced by mixed fermentation were linked to higher ester concentrations, including isoamyl acetate, ethyl isovalerate, ethyl hexanoate, and diethyl succinate. The enhanced esters in mixed fermentation can be attributed to the upregulated alcohol acyltransferase activity and the expressions of ACC1, FAS2, ELO1 and ATF1 genes in late fermentation stage via the cell-cell contact between T. delbrueckii and S. cerevisiae. These findings can deepen the understanding of the interaction between non-Saccharomyces and S. cerevisiae in ester production, assisting wineries in effectively controlling wine aroma through mixed fermentations.

Effects of Phenolic Evolution on Color Characteristics of Single-Cultivar Vitis vinifera L. Marselan and Merlot Wines during Vinification and Aging

The loss of red hue in dry red wine has been a persistent issue for wine enterprises in western China. We investigated the changes in anthocyanins and non-anthocyanin phenols during the industrial-scale fermentation and one-year bottle aging of Vitis vinifera L. Merlot and Vitis vinifera L. Marselan, respectively, using the grapes in the Ningxia region. We also examined their correlation with color characterization. The study found that both anthocyanins and non-anthocyanin phenolics were rapidly extracted from grapes during alcohol fermentation. However, their concentrations decreased rapidly during malolactic fermentation. On the other hand, Vitisin A and Vitisin B were formed during alcoholic fermentation and decreased slowly from malolactic fermentation to storage period. Directly polymerized pigments (F-A and A-F), bridged polymerized pigments (A-e-F), and flavanyl-pyranoanthocyanins (A-v-F) from the reactions of anthocyanins (A) and flavan-3-ols (F), as well as pinotins were generated during the later stages of alcoholic fermentation, and remained at a high level throughout malolactic fermentation and bottle storage. Partial least squares regression and Pearson correlation analyses revealed that the red hue (a* value) of 'Merlot' and 'Marselan' wines was closely associated with monomeric anthocyanins and F-A type pigments. Furthermore, four pinotin components were positively correlated with the red hue (a* value) of 'Merlot' wine. These primary red components of the two varieties had a positive correlation with the level of flavan-3-ols. The data suggest that elevating the flavan-3-ol concentration during fermentation aids in improving the color stability of red wine.

Aroma enhancement of blueberry wine by postharvest partial dehydration of blueberries

Blueberries with 20%, 30%, and 40% weight loss were used for winemaking, aiming to explore the feasibility of applying postharvest dehydration for improving blueberry wine aroma. Postharvest dehydration decreased the titratable acidity of blueberries and their resultant wines. Total anthocyanins and phenols in blueberries with 30% weight loss were increased by 25.9% and 16.1%, respectively, due to concentration effects, while further dehydration resulted in a decline. Similar trends were observed in blueberry wines. Moderate postharvest dehydration increased total terpenes, benzeneacetaldehyde and phenylethyl alcohol, ethyl butanoate, methyl salicylate, 1-hexanol, and γ-nonalactone content in blueberries and wines, which could enhance the floral, fruity, and sweet notes of blueberry wines. Wines made from blueberries under severe dehydration (40% weight loss) had the lowest overall aroma score, which was related to the higher content of 4-ethyl-phenol and 4-ethylguaiacol. In conclusion, moderate postharvest dehydration benefited the aroma enhancement of blueberry wine.

The Application of Non-Thermal Technologies for Wine Processing, Preservation, and Quality Enhancement

Recently, non-thermal wine processing technologies have been proposed as alternatives to conventional winemaking processes, mostly with the aims to improve wine quality, safety, and shelf-life. Winemakers typically rely on sulfites (SO2) to prevent wine oxidation and microbial spoilage, as these processes can negatively affect wine quality and aging potential. However, SO2 can trigger allergic reactions, asthma, and headaches in sensitive consumers, so limitations on their use are needed. In red winemaking, prolonged maceration on skins is required to extract enough phenolic compounds from the wine, which is time-consuming. Consequently, the wine industry is looking for new ways to lower SO2 levels, shorten maceration times, and extend shelf life while retaining wine quality. This review aggregates the information about the novel processing techniques proposed for winemaking, such as high-pressure processing, pulsed electric field, ultrasound, microwave, and irradiation. In general, non-thermal processing techniques have been shown to lead to improvements in wine color characteristics (phenolic and anthocyanin content), wine stability, and wine sensory properties while reducing the need for SO2 additions, shortening the maceration time, and lowering the microbial load, thereby improving the overall quality, safety, and shelf life of the wines.

Extraction of functional extracts from berries and their high quality processing: a comprehensive review

Berry fruits have attracted increasing more attention of the food processing industry as well as consumers due to their widely acclaimed advantages as highly effective anti-oxidant properties which may provide protection against some cancers as well as aging. However, the conventional extraction methods are inefficient and wasteful of solvent utilization. This paper presents a critical overview of some novel extraction methods applicable to berries, including pressurized-liquid extraction, ultrasound-assisted extraction, microwave-assisted extraction, supercritical fluid extraction, enzyme-assisted extraction as well as some combined extraction methods. When combined with conventional methods, the new technologies can be more efficient and environmentally friendly. Additionally, high quality processing of the functional extracts from berry fruits, such as refined processing technology, is introduced in this review. Finally, progress of applications of berry functional extracts in the food industry is described in detail; this should encourage further scientific research and industrial utilization.

Influence of Saccharomyces and non-Saccharomyces Yeasts in the Formation of Pyranoanthocyanins and Polymeric Pigments during Red Wine Making

Yeast are able to modulate many sensory parameters of wines during red must fermentation. The effect on color and on the formation of derived pigments during fermentation has been studied thoroughly since the 90s. Yeast can increase grape anthocyanin’s color by acidification by hyperchromic effect (increase of flavylium molecules). Recent studies with non-Saccharomyces species, as Lachancea thermotolerans, described the intense effect of some strains on anthocyanin’s color, and subsequent, stability, by strongly reducing wine’s pH during fermentation. Moreover, selected yeast strains of Saccharomyces have been shown to release metabolites such as pyruvic acid or acetaldehyde that promote the formation of vitisin A and B pyranoanthocyanins during must fermentation. Schizosaccharomyces pombe, because of its specific metabolism, can produce higher concentrations of pyruvate, which enhances the formation of vitisin A-type derivatives. The hydroxycinnamate decarboxylase activity that some Saccharomyces strains express during fermentation also promotes the formation of vinylphenolic derivatives. Some non-Saccharomyces species, such as S. pombe or P. guilliermondii can also improve the production of these derivatives compared to selected strains of Saccharomyces cerevisiae. Lastly, some yeasts are also able to modulate the formations of polymeric pigments between grape anthocyanins and flavonoids, such as catechins and procyanidins.

Effects of Granucol activated carbons on sensory properties of sea-buckthorn (Hippophae rhamnoides L.) wines

The paper introduces some experimental data on activated carbons of Granucol series that can improve the colour of sea-buckthorn wines and stabilize them during storage. Such treatment is necessary because sea buckthorn contains reactive phenolic compounds that trigger non-enzymatic oxidative browning in sea-buckthorn wine. A di- rect regulation of the amount of phenolic compounds can improve sensory characteristics of sea-buckthorn wines, as well as increase their shelf-life. The research featured table dry wine made of 10 varieties of sea buckthorn grown in the Altai region. The chromatic characteristics were studied according to the existing guidelines of the International Organization of Vine and Wine (OIV, France). The index of yellowness served as an additional indicator for the co- lour assessment of the sea-buckthorn wines. Another objective indicator of colour assessment was the index of the displacement of the colour of x and y coordinates that corresponded with the green-red and yellow-blue chromatic axes. When 20–60 mg/100 ml of Granucol activated carbon was used during the winemaking process, it significantly improved the harmony of the sea-buckthorn wines. In particular, it had a positive effect on the colour characteristics. Granucol carbon reduced such unfavourable taste characteristics as excessive roughness (the total amount of polyphe- nolic compounds fell by 1.5–2 times) and significantly improved the aroma by erasing the yeasty and fusel odours.