Enological potential of chestnut wood for aging Tempranillo wines Part II: Phenolic compounds and chromatic characteristics

Alternative Woods in Oenology: Volatile Compounds Characterisation of Woods with Respect to Traditional Oak and Effect on Aroma in Wine, a Review

The interest of winemakers to find new woods that can give their wines a special personality and the need for cooperage wood have led to the use of other woods than traditional oak. The aroma of wines is undoubtedly one of the quality factors most valued by consumers. Volatile compounds from wood are transferred to wines during ageing. The type and quantity of aromas in wood depend on several factors, with the species, origin and cooperage treatments, particularly toasting, being very important. The transfer of volatile compounds to the wine depends not only on the wood but also on the wine itself and the type of ageing. This review therefore aims to recapitulate the volatile composition of alternative oenological woods at different cooperage stages and to compare them with traditional woods. It also summarises studies on the effect of wine aromas during ageing both in barrels and with fragments of alternative woods. In summary, it is observed that both woods and wines aged with alternative species of the Quercus genus present the same volatile compounds as traditional ones, but differ quantitatively; however, non-Quercus woods also differ qualitatively.

Wood powders of different botanical origin as an alternative to barrel aging for red wine

Wood powders are produced in large quantity as by-product of barrel, staves and chips industry. Differently from larger particles (chips), the use of wood powders in winemaking is not admitted (Regulation (CE) n. 934/2019); however, it could represent a cheap and sustainable alternative for the accelerated aging of red wine. To evaluate their potential use in winemaking, a comparative study on the use of wood powders from oak, chestnut and acacia wood for the accelerated aging of red wine (cv. Aglianico) was conducted. This alternative aging was compared to the aging in wood barrels from the same botanical species. The wine aged in contact with powders underwent a quicker evolution of polyphenolic fraction. After 15 days of contact, the loss of total anthocyanins was higher than that observed after 6 months of aging in barrels (from 4 to 14% with respect to the corresponding kind of barrel). The amount of polymeric pigments tannins–anthocyanins–tannins in wines aged in contact with powders was higher respect to the wines aged in barrels (from 7 to 21% with respect to the corresponding kind of barrel), while the greatest loss of total tannins was detected in the oak barrels (28% less with respect to the control). There were several differences in wine phenolic acids due to wood botanical origin, with the clearest differences being between oak and the alternative wood species (chestnut and acacia). Also, there was a significant botanical effect on sensory profiles. Indeed, both among barrels and among powders, oak wood was the one that gave the strongest wood odor character. However, all the treatments with wood powders (oak, acacia and chestnut) preserved the fruity character of wine, conferring in the meanwhile non-dominant woody notes.

Castanea sativa shells: A review on phytochemical composition, bioactivity and waste management approaches for industrial valorization

Castanea sativa is an outstanding species that represents a valuable natural resource for rural populations. C. sativa shells (CSS), an abundant agro-industrial by-product generated during chestnut peeling process, is commonly discarded or used as fuel. Nevertheless, CSS produced are not depleted by this application and huge amounts are still available, being particularly rich in bioactive compounds (polyphenols, vitamin E, lignin and oligosaccharides) with health benefits. Phytochemical studies reported not only antioxidant and antimicrobial activities, but also anti-inflammatory, anticancer, hypolipidemic, hypoglycemic and neuroprotective activities. The application of a suitable extraction technique is required for the isolation of bioactive compounds, being green extraction technologies outstanding for the industrial recovery of chestnut shells' bioactive compounds. CSS were highlighted as remarkable sources of functional ingredients with promising applications in food and nutraceutical fields, mainly as natural antioxidants and effective prebiotics. This review aims to summarize the phytochemical composition and pro-healthy properties of CSS, emphasizing the sustainable extraction techniques employed in the recovery of bioactive compounds and their potential applications in food and nutraceutical industries.

Phenolic Compounds as Markers of Wine Quality and Authenticity

Targeted and untargeted determinations are being currently applied to different classes of natural phenolics to develop an integrated approach aimed at ensuring compliance to regulatory prescriptions related to specific quality parameters of wine production. The regulations are particularly severe for wine and include various aspects of the viticulture practices and winemaking techniques. Nevertheless, the use of phenolic profiles for quality control is still fragmented and incomplete, even if they are a promising tool for quality evaluation. Only a few methods have been already validated and widely applied, and an integrated approach is in fact still missing because of the complex dependence of the chemical profile of wine on many viticultural and enological factors, which have not been clarified yet. For example, there is a lack of studies about the phenolic composition in relation to the wine authenticity of white and especially rosé wines. This review is a bibliographic account on the approaches based on phenolic species that have been developed for the evaluation of wine quality and frauds, from the grape varieties (of V. vinifera and non vinifera), to the geographical origin, the vintage year, the winemaking process, and wine aging. Future perspectives on the role of phenolic compounds in different wine quality aspects, which should be still exploited, are also outlined.

A quarter century of wine pigment discovery

The red grape berry pigments, anthocyanins, were characterized in the early 20th century, but investigations of wine pigments were stymied during that era. The question of their identity was a major challenge for wine chemists. A number of techniques showed that the pigments were polymeric in nature. Some structures were postulated by mid-century based on reactions between anthocyanins and condensed tannin, and later postulated wine pigments were observed in model reactions. Some related compounds were then observed in wine. By the end of the 20th century, the ionization of non-volatiles for mass spectrometry opened the door to these compounds. In addition, a new class of compounds was observed, the pyranoanthocyanins, a product of fermentation and aging metabolites with anthocyanins. These compounds possess the pigment stability to SO₂ and pH change that is characteristic of aged red wine. Aging experiments show a dynamic situation with shifts in the population of pigment classes over time. The very large number of diverse pigments explains why it has been so difficult to answer the century-old question of the structure of wine pigments. Our current understanding is founded on the use of mass spectral analysis using electrospray and related ionization techniques over the last 25 years. Future progress will rely on more sophisticated analysis of this very complex mixture of substances. © 2019 Society of Chemical Industry.

Evolution of the Phenolic Fraction and Aromatic Profile of Red Wines Aged in Oak Barrels

Various changes occur in red wine during aging in oak barrels. Among these, the variation of the polyphenolic fraction and the transfer of aromatic compounds to the wine from oak wood are of great importance. The aim of the present work is to compare the chemical composition of wines aged in different new oak barrels with similar commercial denominations. During 8 months, the total polyphenol index (TPI), color parameters, anthocyanins and pyranoanthocyanins, and wood aromatic compounds were periodically evaluated. The measurement of the TPI and color parameters was similar in all wines, but significant differences were found in total anthocyanin and vitisin content and in certain aromatic compounds belonging to volatile phenols, furanic compounds, and phenolic aldehydes. The results obtained indicate the need for the winemaker to carry out preliminary tests in order to be able to choose the wood that best suits the sensorial profile of the wine.

Green-Sustainable Recovery of Phenolic and Antioxidant Compounds from Industrial Chestnut Shells Using Ultrasound-Assisted Extraction: Optimization and Evaluation of Biological Activities In Vitro

Chestnut processing industry generates large amounts of by-products, including leaves, burs and shells that are a source of bioactive compounds. The purpose of this study was to establish an ultrasound-assisted extraction (UAE) of phenolic and antioxidant compounds from industrial chestnut shells. A central composite design (CCD) was conducted to analyze the effects of time (4–46 min) and temperature (34–76 °C) in the antioxidant activity (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and ferric reducing antioxidant power (FRAP)) and total phenolic compounds (TPC) of chestnut shells extracts. The optimal extraction conditions were obtained at 70 °C for 40 min. The optimal extract was characterized regarding phenolic profile, radical scavenging capacity, and effects on intestinal and dermal cell lines. The optimal extract revealed high amounts of ellagic acid (40.4 µg/mg dw), followed by caffeic acid derivative (15.4 µg/mg dw) and epigallocatechin (15.3 µg/mg dw). Indeed, the extract exhibited the highest scavenging efficiencies against NO● (IC₅₀ = 0.1 µg/mL) and HOCl (IC₅₀ = 0.7 µg/mL) and did not conducted to a decrease on HaCaT and HFF-1 viability up to 100 μg/mL. Oppositely, a decrease on Caco-2 and HT29-MTX viability was observed. This study suggests that UAE could be a sustainable option to valorize chestnut shells as raw material for different industries.

Volatilome fingerprint of red wines aged with chips or staves: Influence of the aging time and toasting degree

The influence on aroma compounds chips or staves and toasting degree have been analyzed in red wines aged for two periods of time. Ethyl propanoate, ethyl butanoate, ethyl octanoate, ethyl acetate, isoamyl acetate, isobutanol, 2-methyl-1-butanol, 2-phenylethanol, E-2-hexenol, octanal, nonanal, decanal, γ-nonalactone, furfural, 5-methylfurfural, 2-methoxy-4-vinylphenol and cis-whiskey lactone were the compounds that contribute the most to the aroma series profile. By means of principal components analysis, esters were related to the aging time; cis-whiskey lactone with the type of wood pieces and octanal, 5-methyl furfural and cis-whiskey lactone with the toasting degree. Star plot show that woody aroma compounds are dominant in wines aged with low toasting degree oak pieces, whereas medium plus toasted pieces increased the concentration of aroma compounds with fruity aroma descriptors. Wines with prominent fruity or woody aromas can be obtained depending upon the degree of toasting of wood pieces used for aging.

Use of Oak Fragments during the Aging of Red Wines. Effect on the Phenolic, Aromatic, and Sensory Composition of Wines as a Function of the Contact Time with the Wood

The use of oak fragments allows wine cellars to reduce costs and the length of wine aging compared to traditional aging in oak barrels in the winery. The main objective of this work was to study the effect of the use of oak fragments on the volatile, phenolic, and organoleptic characteristics of Tempranillo red wines, as a function of the contact time between the wood and the wine. The results showed important changes in the wines’ colorimetric parameters after two months of contact time. Extraction kinetics of volatile compounds from the wood was highest during the first month of contact for chips, variable for staves, and slower and continuous over time for barrels. Wines macerated with fragments showed the best quality in short periods of aging, while barrel-aged wines improved over the time they spent in the barrel. In addition, the results allowed an analytical discrimination between the wines aged with oak fragments and those aged in oak barrels, and between chips and staves, just as at the sensory level with triangular tasting tests. In conclusion, the use of oak fragments is a suitable practice for the production of red wines, which may be an appropriate option for wines destined to be aged for short periods.

Different Woods in Cooperage for Oenology: A Review

Contact of wine with wood during fermentation and ageing produces significant changes in its chemical composition and organoleptic properties, modifying its final quality. Wines acquire complex aromas from the wood, improve their colour stability, flavour, and clarification, and extend their storage period. New trends in the use of barrels, replaced after a few years of use, have led to an increased demand for oak wood in cooperage. In addition, the fact that the wine market is becoming increasingly saturated and more competitive means that oenologists are increasingly interested in tasting different types of wood to obtain wines that differ from those already on the market. This growing demand and the search for new opportunities to give wines a special personality has led to the use of woods within the Quercus genus that are different from those used traditionally (Quercus alba, Quercus petraea, and Quercus robur) and even woods of different genera. Thus, species of the genus Quercus, such as Quercus pyrenaica Willd., Quercus faginea Lam., Quercus humboldtti Bonpl., Quercus oocarpa Liebm., Quercus frainetto Ten, and other genera, such as Robinia pseudoacacia L. (false acacia), Castanea sativa Mill. (chestnut), Prunus avium L. and Prunus cereaus L. (cherry), Fraxinus excelsior L. (European ash), Fraxinus americana L. (American ash), Morus nigra L, and Morus alba L. have been the subject of several studies as possible sources of wood apt for cooperage. The chemical characterization of these woods is essential in order to be able to adapt the cooperage treatment and, thus, obtain wood with oenological qualities suitable for the treatment of wines. This review aims to summarize the different species that have been studied as possible new sources of wood for oenology, defining the extractable composition of each one and their use in wine.

New Strategies to Improve Sensorial Quality of White Wines by Wood Contact

Ageing wine is a common practice used in winemaking, since the quality and sensory profile increase due to the extractable compounds coming from wood, by means of barrels or chips. The quantitative and qualitative compounds of the wood depend on the species, its origins and the treatments applied in cooperages. Traditionally, oak wood species are most often used in cooperage, specifically Quercus alba (Q. alba), Known as American oak and Quercus robur (Q. robur) and Quercus petraea (Q. petraea), both known as French oak. Although this stage is very common for red wines, its use is still restricted in the case of white wines. However, this topic is particularly interesting, since due to the sensorial benefits of wood contact, the option for ageing white wines in barrels or chips could be chosen by winemakers. This review compiles the novel strategies applied to white wines by means of wood contact in recent years with the aim to increase wine quality and sensorial features.

Cytotoxic triterpenoids isolated from sweet chestnut heartwood (Castanea sativa) and their health benefits implication

For centuries wood containers have been used in aging of wines and spirits, due to the pleasant flavors they give to the beverages. Together with oak, sweet chestnut wood (Castanea sativa) have been often used for such purpose. The maturation process involves the transfer of secondary metabolites, mainly phenolics, from the wood to the liquid. At the same time, other metabolites, such as triterpenoids and their glycosides, can also be released. Searching for the extractable triterpenoids from sweet chestnut heartwood (C. sativa), two new ursane-type triterpenoid saponins named chestnoside A (1) and chestnoside B (2), together with two known oleanen-type analogs (3 and 4) were isolated and characterized. The cytotoxicity of isolated compounds was tested against two cancer cell lines (PC3 and MCF-7), and normal lymphocytes. Breast cancer cells (MCF-7) were more affected by tested compounds than prostate cancer cells (PC3). Chestnoside B (2) exhibited the strongest cytotoxicity with an IC₅₀ of 12.3 μM against MCF-7 cells, lower than those of positive controls, while it was moderately active against normal lymphocytes (IC₅₀ = 67.2 μM). These results highlight the occurrence of triterpenoid saponins in sweet chestnut heartwood and their potential for the chemoprevention of breast cancer.

Impact of Sucrose Addition on the Physiochemical Properties and Volatile Compounds of “Shuangyou” Red Wines

“Shuangyou,” a Vitis amurensis Rupr. variety, is widely cultivated in northeastern and western China. Its berries have high acidity and low sugar content. In this study, different proportions of sucrose were added to the must samples during fermentation to investigate the effect of sugar on the physicochemical properties and volatile compounds of “Shuangyou” wines. The addition of sucrose significantly improved yeast growth and alcohol production, altered the color qualities, and slightly decreased titratable acidity during fermentation. The highest tested proportion of added sucrose resulted in the highest maximum yeast counts and final ethanol concentrations. Moreover, 37 volatile compounds (esters, alcohols, fatty acids, ketones, and aldehydes) were identified and quantified by solid-phase microextraction with gas chromatography-mass spectrometry. The concentrations of these compounds were correlated with the addition of sucrose. Furthermore, the addition of 100 g/L sucrose was sufficient for improving the concentrations of the aromatic compounds. The increase in ester, alcohol, and fatty acid concentration led to a positive OAVs impact (odor activity value > 1) at the end of fermentation.

A review of polyphenolics in oak woods

Polyphenolics, which are ubiquitous in plants, currently are among the most studied phytochemicals because of their perceptible chemical properties and antioxidant activity. Oak barrels and their alternatives, which are widely used in winemaking nowadays, contribute polyphenolics to wines and are thought to play crucial roles in the development of wines during aging. This study summarizes the detailed information of polyphenolics in oak woods and their products by examining their structures and discussing their chemical reactions during wine aging. This paper evaluates the most recent developments in polyphenolic chemistry by summarizing their extraction, separation, and their identification by the use of chromatographic and spectral techniques. In addition, this paper also introduces polyphenol bioactive ingredients in other plant foods.

Castanea sativa by-products: a review on added value and sustainable application

Castanea sativa Mill. is a species of the family Fagaceae abundant in south Europe and Asia. The fruits (chestnut) are an added value resource in producing countries. Chestnut economic value is increasing not only for nutritional qualities but also for the beneficial health effects related with its consumption. During chestnut processing, a large amount of waste material is generated namely inner shell, outer shell and leaves. Studies on chestnut by-products revealed a good profile of bioactive compounds with antioxidant, anticarcinogenic and cardioprotective properties. These agro-industrial wastes, after valorisation, can be used by other industries, such as pharmaceutical, food or cosmetics, generating more profits, reducing pollution costs and improving social, economic and environmental sustainability. The purpose of this review is to provide knowledge about the type of chestnut by-products produced, the studies concerning its chemical composition and biological activity, and also to discuss other possible applications of these materials.

The phenolic chemistry and spectrochemistry of red sweet wine-making and oak-aging

A natural sweet wine (NSW) was made with dried grapes from Vitis vinifera L. cv Garnacha Tintorera. A fortified sweet wine (FSW) was also obtained: the maceration-alcoholic fermentation of Garnacha Tintorera must was stopped by addition of ethanol 96% (v/v). UV/Vis spectrophotometry and HPLC/DAD-ESI/MS were applied to determine, respectively, the evolution of colour and phenolic compounds in Garnacha Tintorera based-sweet wines during aging. In sweet wines, aging decreased a(∗) (red/green), colour saturation and lightness and increased b(∗) (yellow/blue), and hue angle. Most of the phenolic compounds determined, such as anthocyanins, esters of hydroxycinnamic acids, flavan-3-ols monomers, oligomers and polymers decreased in both sweet wines during aging. On the contrary, hydroxybenzoic and hydroxycinnamic acids and vitisins increased after one year of aging. Despite that both terminal and extension subunit compositions show very small changes, mean degree of polymerisation of proanthocyanidins decline slightly as aging progressed in both sweet wines.