Co-fermentation of red grapes and white pomace: A natural and economical process to modulate hybrid wine composition

Influence of Grape Flesh on the Retention and Composition of Polyphenols from Skins and Seeds

This study examined the impact of grape flesh polysaccharide, protein, and amino acid contents on polyphenol retention from skins and seeds in Pinot noir (Vitis vinifera) and cold-hardy interspecific cultivars Marquette and Frontenac (Vitis spp.). After isolating grape tissues (skin, seed, and flesh), they were soaked either individually or combined with other tissues in a wine-like solution for up to 7 days. Findings revealed that flesh significantly reduces the concentration of condensed tannin, and mono- and diglucoside forms of anthocyanins in the supernatants, due to its rich content in polysaccharides and proteins. Frontenac skin and flesh tissues were the main sources of soluble proteins, amino acids, and soluble polysaccharides. Surprisingly, Marquette exhibited a higher retention of skin tannin than Pinot noir, likely due to its smaller tannin molecular mass, and a potential competitive effect with anthocyanins for the binding sites of flesh.

Oenological potential of wines produced from disease-resistant grape cultivars

Within the EU, changes in policy and public sentiment have made it more urgent to consider the adoption of sustainable agricultural practices. Consequently, one of the EU's goals is to reduce pesticide use by 50 per cent by 2030, including in viticulture. One of the proposed approaches is to expand the use of disease resistant hybrid grape-cultivars (DRHGC), such as 'PIWI' grapes (German, Pilzwiderstandsfähige Rebsorten), and to introduce new DRHGCs. However, the characteristics of DRHGCs are different from those of Vitis vinifera, which makes it necessary to take measures and make changes in winemaking technology to maintain high wine quality. This paper examines the chemistry of wines made from DRHGC and discusses their impact on aroma and flavor profiles. It also reviews the main winemaking practices suggested to produce high-quality wines from DRHGCs. The chemistry of DRHGCs is different to wine produced from V. vinifera, which can lead to both challenges during winemaking and unusual flavor profiles. Although newer DRHGCs have been bred to avoid unexpected flavors, many DRHGCs are still rich in proteins and polysaccharides. This can make tannin extraction difficult and produce wines with little astringency. In addition to this, new or alternative winemaking techniques such as thermovinification and the use of alternative yeast strains (non-Saccharomyces) can be used to produce wines from DRHGCs that are acceptable to consumers.

Strategies in vineyard establishment to face global warming in viticulture: a mini review

Different technological solutions are developing in the wine industry to mitigate the negative effects of the current global warming to mainly achieve wines with a lower alcohol content. These proposed solutions mostly act at the oenological level and are focused on intervening in the raw material to be transformed; that is, on reducing the concentration of sugar in the must using filtration techniques or also on wine dealcoholizing by physical processes. These techniques are intended to offer solutions and respond to new consumer expectations, but they may be considered too artificial to be widely accepted. In this way, viticultural strategies may offer a natural solution to obtain grapes with low sugar content, maximizing their quality by delaying ripening. This mini review surveys the viticultural strategies that can be applied in the establishment of a vineyard - that is, when it comes to planting of a new vineyard - such as vineyard altitude, latitude, orientation, and slope, as well as rootstock, variety, clone, training system, and row orientation and slope, with the aim to mitigate the negative effects of climate change on grape and wine quality and to delay grape maturation. Finally, we propose a ponderation of the strategies discussed to contextualize its importance to face global warming in viticulture. © 2020 Society of Chemical Industry.

Impact of a double post-fermentative maceration with ripe and overripe seeds on the phenolic composition and color stability of Syrah red wines from warm climate

The post-fermentative double addition of Pedro Ximénez cv seeds obtained from natural matured grapes (ripe seeds, RS) and postharvest sun-dried grapes (overripe seeds, OS) were studied as sustainable enological alternatives to conventional vinification (CW) to improve the stability of Syrah wines produced in a warm climate. The phenolic composition was assessed by rapid resolution liquid chromatography, copigmentation/polymerization processes by spectrophotometry, and color quality and stability by Differential Colorimetry. OSW and RSW wines enriched their total phenolic content, being the effect more pronounced with overripe seeds (by 23% versus 10%). OSW differences were found for gallic acid, monomeric flavan-3-ols, and procyanidins compared to CW, and for (+)-catechin, procyanidin B2-3-O-gallate and the tetramer to RSW. Phenolic changes were related to higher color intensity in seed-added wines. OSW having higher percentage of polymeric pigments maintained for longer time the chromatic improvement, being visually darker and more intense than final CW and RSW.

Pre-fermentative cold maceration in presence of non-Saccharomyces strains: Evolution of chromatic characteristics of Sangiovese red wine elaborated by sequential inoculation

Two different Metschnikowia strains (M. pulcherrima MP 346 or M. fructicola MF 98-3) were applied for the first time, during pre-fermentative cold maceration (PCM) in order to enhance the properties and stability of Sangiovese wine color. During the 2014 and 2015 vintages a total of eight wines were produced with 24 h of cold maceration (PCM 24 h) or 72 h (PCM 72 h), respectively. PCM was carried out in presence of MP 346 or MF 98-3 or pectic enzyme (Cuvée Rouge). The sequential inoculation of S. cerevisiae strain was carried out at the end of PCM. After 12 months in the bottle, the MP 346 and MF 98-3 wines contained much higher levels of total flavonoids than the Control sample for both vintages and regardless PCM duration. Moreover, in both vintages only MF 98-3 showed a higher color intensity than the Control sample after 12 months in the bottle. However, neither PCM duration nor the microbial/enzymatic treatment increased the level of anthocyanins at draining off. Both wines produced by the pre-fermentative inoculum with Metschnikowia strains (MP 346 and MF 98-3) retained their red hue, regardless the duration of pre-fermentative and fermentative macerations, while the Control wines were characterized by faster rates of color loss.