Corky off-flavor compounds in cork planks at different storage times before processing. Influence on the quality of the final stoppers.

BACKGROUND: Cork companies store cork planks before processing them for a minimum of 6 months to dry up and to stabilize their texture and chemical composition, although many companies extend this storage period up to 12 months. However, there is no information about the influence of this seasoning period on their 'corky' off flavors. For this reason, the main compounds responsible for the 'cork taint' of planks stored before processing from 6 to 12 months were investigated. RESULTS: Four haloanisoles and three halophenols were identified: 2,4,6-trichloroanisole (TCA), 2,3,4,6-tetrachloroanisole (TeCA), pentachloroanisole (PCA), 2,4,6-tribromoanisole (TBA), 2,4,6-trichlorophenol (TCP), 2,3,4,6-tetrachlorophenol (TeCP), and 2,4,6-tribromophenol (TBP). All of the planks presented some haloanisole or halophenol after 6 and 9 months of storage, which practically disappeared after a year of storage. These compounds were only detected in the cork stoppers made from planks with 6 and 9 months of storage. Of the alkylmethoxypyrazines, 2-methoxy-3,5-dimethylpyrazine (MDMP), 3-isopropyl-2-methoxypyrazine (IPMP), and 3-isobutyl-2-methoxypyrazine (IBMP) were identified. The MDMP was detected in a larger number of planks with 6 months of storage and at higher concentrations than IPMP and IBMP. However, MDMP was not detected in the cork stoppers made from planks at 6, 9, and 12 months of storage. CONCLUSION: A storage time of 6 months before processing of raw cork planks would be sufficient to obtain cork stoppers with low concentrations of corky off-flavor compounds. An increase in storage up to 9 or 12 months would result in practically 'cork taint'-free natural stoppers. © 2021 Society of Chemical Industry.

Fingerprints of acacia aging treatments by barrels or chips based on volatile profile, sensorial properties, and multivariate analysis.

BACKGROUND: Despite the acceptance of the use of chips as an alternative enological practice to traditional barrels, there is substantial interest in looking for parameters that enable the aging technique to be identified. In the present study, the volatile compound composition and sensorial characteristics of wines aged with chips and barrels of acacia wood were monitored with the aim of finding fingerprints that could be used to discriminate between the two types of aging. RESULTS: Principal component analysis (PCA) calculated from chemical outputs permitted the two aging techniques to be distinguished. After 4 months of aging in barrels, concentrations of vanillin, ferulic acid, syringaldehyde, and furfural decreased considerably due to the higher oxidation produced by the acacia wood's porosity. This fact made it more difficult to discriminate between those wines aged in barrels for the longest times. On the other hand, PCA applied to sensorial data allowed a clear differentiation between wines aged in acacia barrels for longer periods and those macerated with chips, due to the notable presence of sensory attributes described as acacia wood, nutty, honeyed, and toasty. CONCLUSION: Chemical and sensorial data can be regarded as complementary methods to obtain fingerprints that enable differentiation between the two different aging techniques by means of acacia wood. © 2018 Society of Chemical Industry.

Cyclic polyalcohols: fingerprints to identify the botanical origin of natural woods used in wine aging.

Cyclic polyalcohol composition of 80 natural wood samples from different botanical species, with the majority of them used in the oenology industry for aging purposes, has been studied by gas chromatography-mass spectrometry (GC-MS) after its conversion into their trimethylsilyloxime derivatives. Each botanical species showed a different and specific cyclic polyalcohol profile. Oak wood samples were characterized by the richness in deoxyinositols, especially proto-quercitol. Meanwhile, other botanical species showed a very low content of cyclic polyalcohols. The qualitative and quantitative study of cyclic polyalcohols was a useful tool to characterize and differentiate woods of different botanical origin to guarantee the authenticity of chips used in the wine-aging process. Monosaccharide composition was also analyzed, showing some quantitative differences among species, but cyclic polyalcohols were the compounds that revealed the main differentiation power.