Effect of the type of oak barrels employed during ageing on the ellagitannin profile of wines

[EN] Background and Aims: Ellagitannins released from wood to wine during barrel ageing can affect wine colour and astringency. This work aimed to examine the influence that oak wood type (French or American) and age (first-fill or second-fill) of barrels has on the concentration of individual ellagitannins and their evolution during winemaking and ageing. Methods and Results: The ellagitannin composition of red wines during ageing was determined by HPLC-MS/MS-multiple reaction monitoring. Differences in the extractability and stability of the individual ellagitannins were observed. Moreover, the ellagitannin composition of wines was determined by the type of barrel. Wines aged in new French oak barrels showed a concentration of ellagitannin about twofold higher than that aged in American or in second-fill French ones. The vescalagin/castalagin ratio was higher in wines aged in French oak barrels than that in wines aged in American barrels. Wine samples were grouped by discriminant analysis into three groups depending on the type of barrel employed during ageing. Conclusions: The ellagitannin profile of aged red wines is strongly influenced by the type of oak barrel employed.Wines aged in new French oak barrels can be differentiated from those aged in second-fill French or in new American oak barrels by the ellagitannin concentration, whereas the vescalagin/castalagin ratio may assist in tracing the oak type (French or American) of the barrels. Significance of the Study: The ellagitannin concentration along with the vescalagin/castalagin ratio in red wines aged in oak barrels can be employed for tracing the oak type of the barrels

Understanding the ellagitannin extraction process from oak wood

[EN] The extractability of the main oak ellagitannins has been studied in five model solutions containing different types of oak chips (two sizes and different toasting degrees for each size). A new extraction kinetic model has been proposed from the quantitative experimental results obtained by means of HPLCeESI-MS/MS-multiple reaction monitoring method. The model considers an initial extraction (i.e., washing step) followed by a diffusion step, which involves two different processes that follow first-order kinetics at different rates. Differences in the extractability of the ellagitannins in the different model solutions have been observed and explained on the basis of the kinetic model here proposed

Validation of a Mass Spectrometry Method To Quantify Oak Ellagitannins in Wine Samples

[EN] Detection and individual quantification of oak wood ellagitannins in oak barrel aged red wine samples are difficult mainly due to their low levels and the similarity between their structures. In this work, a quantification method using mass spectrometry has been developed and validated to quantify wine ellagitannins after sample fractionation with a previously reported method. The use of an internal standard is a requirement to correct mass signal variability. (−)-Gallocatechin, among the different tested compounds, was the only one that proved to be a suitable internal standard making possible the accurate and individual quantification of the main oak wood ellagitannins. The developed methodology has been used to detect and quantify these ellagitannins in different Spanish commercial wines, proving its usefulness

Chemistry of Secondary Polyphenols Produced during Processing of Tea and Selected Foods

This review will discuss recent progress in the chemistry of secondary polyphenols produced during food processing. The production mechanism of the secondary polyphenols in black tea, whisky, cinnamon, and persimmon fruits will be introduced. In the process of black tea production, tea leaf catechins are enzymatically oxidized to yield a complex mixture of oxidation products, including theaflavins and thearubigins. Despite the importance of the beverage, most of the chemical constituents have not yet been confirmed due to the complexity of the mixture. However, the reaction mechanisms at the initial stages of catechin oxidation are explained by simple quinone–phenol coupling reactions. In vitro model experiments indicated the presence of interesting regio- and stereoselective reactions. Recent results on the reaction mechanisms will be introduced. During the aging of whisky in oak wood barrels, ellagitannins originating from oak wood are oxidized and react with ethanol to give characteristic secondary ellagitannins. The major part of the cinnamon procyanidins is polymerized by copolymerization with cinnamaldehyde. In addition, anthocyanidin structural units are generated in the polymer molecules by oxidation which accounts for the reddish coloration of the cinnamon extract. This reaction is related to the insolubilization of proanthocyanidins in persimmon fruits by condensation with acetaldehyde. In addition to oxidation, the reaction of polyphenols with aldehydes may be important in food processing

Interactions between wine phenolic compounds and human saliva in astringency perception

[EN] Astringency is a complex perceptual phenomenon involving several sensations that are perceived simultaneously. The mechanism leading to these sensations has been thoroughly and controversially discussed in the literature and it is still not well understood since there are many contributing factors. Although we are still far from elucidating the mechanisms whereby astringency develops, the interaction between phenolic compounds and proteins (from saliva, oral mucosa or cells) seems to be most important. This review summarizes the recent trends in the protein–phenol interaction, focusing on the effect of the structure of the phenolic compound on the interaction with salivary proteins and on methodologies based on these interactions to determine astringency

First Results of Evaluation of a Falls Clinic

Background: A falls clinic was established at the Waldkrankenhaus St. Marien, Erlangen, Germany. Risk factors for falls in community dwelling elderly adults were assessed and targeted interventions were recommended. Methods: The assessment consisted of patient history, physical examination, evaluation of medication intake, clinical gait assessment, and static posturography and electronic gait analysis. The results of the first 61 assessments are reported in this study. Results: Forty-two participants reported at least one fall in the last 6 months, with half reporting multiple falls. Gait impairments were discovered in 32 participants. Eight participants were diagnosed to suffer from a fall disease (recurring falls during the past 12 months), while nine participants were diagnosed with a fall syndrome (recurring falls during the past 12 months leading to severe injuries). A significant difference between fallers and nonfallers (p < 0.05) was discovered during the patient history and balance assessment using static posturography (p < 0.05). The participants received medical advice, recommendations for individually targeted interventions, and suggestions to see other specialists. Compared to an age-matched local population, our sample showed a higher prevalence of falls. Conclusion: The results showed that a high-risk population attended our falls clinic. We presume that the falls clinic will have a beneficial effect in reducing the prevalence of falls in a high-risk population. Further studies are necessary to test this hypothesis

Decoding the Nonvolatile Sensometabolome of Orange Juice (Citrus sinensis)

Activity-guided fractionation in combination with the taste dilution analysis, followed by liquid chromatography–tandem mass spectrometry and nuclear magnetic resonance experiments, led to the identification of 10 polymethoxylated flavones (PMFs), 6 limonoid glucosides, and 2 limonoid aglycones as the key bitterns of orange juice. Quantitative studies and calculation of dose-over-threshold factors, followed by taste re-engineering, demonstrated for the first time 25 sensometabolites to be sufficient to reconstruct the typical taste profile of orange juices and indicated that not a single compound can be considered a suitable marker for juice bitterness. Intriguingly, the taste percept of orange juice seems to be created by a rather complex interplay of limonin, limonoid glucosides, PMFs, organic acids, and sugars. For the first time, sub-threshold concentrations of PMFs were shown to enhance the perceived bitterness of limonoids. Moreover, the influence of sugars on the perceived bitterness of limonoids and PMFs in orange juice relevant concentration ranges was quantitatively elucidated