Atypical aging off-flavour and relation between sensory recognition and 2-aminoacetophenone in Croatian wines

Abstract

Atypical aging off-flavour (UTA) is not a common wine fault but it is still an interesting topic, due to the complexity of the occurrence, chemical markers, and sensory descriptors. Although 2-aminoacetophenone (AAP) is the main chemical marker, an increase in AAP concentration does not necessarily result with the higher sensory expression of UTA. The goal of this study was to investigate the presence of UTA and the link between UTA olfactory perception and AAP concentration in Croatian wines. All the samples that were rejected due to the UTA in sensory testing during the certification procedure for the market during 2013 -2017 were included in research. The relevant data of origin were analyzed to filter out potential factors of UTA appearance. Sensory analyses were performed with the "100 points" and the "Yes/No" methods, and AAP analyses were done by GC-MS. The appearance of UTA may be associated with the regional origin and extremely poor climatic conditions of a particular year. The results of AAP analyses corroborated the presence of UTA in all samples; the concentrations of AAP were 0.3 -4.4 µg/L. A respective correlation between sensory recognition and the concentration of AAP was specified. This is the first study of sensory detection of UTA and the interconnection with 2-AAP in Croatian wines. The results indicate the need to detect as many volatiles as possible, to explain the difference in olfactory perception of this fault.

Wine Faults: State of Knowledge in Reductive Aromas, Oxidation and Atypical Aging, Prevention, and Correction Methods

“…When this occurs, it is called “atypical wine aging”. Atypical aging (ATA) is not considered a common fault but based on its presence and contribution to the olfactory perception of wine from the view of its chemical and sensory characteristics, it is still a hot topic [ 111 ]. The causes of its occurrence can be found in the vineyard, from where the basic ingredient for wine-producing comes [ 13 ].…”

“…Recognition of ATA off-flavors is due to the wine complexity not being set to the threshold value of AAP concentration, however, several studies into the possible connection between the concentration of AAP and the appearance of off-odors have not confirmed a clear positive correlation [ 111 , 112 , 114 , 115 ]. Although in general, AAP is perceived as the main factor responsible for ATA development.…”

“…In general, threshold concentrations of AAP vary from 0.5 to 1.0 μg L −1 , and in red wines, aroma alteration is observed in concentrations over 1.5 μg L −1 [ 116 ]. Typical off-odors can be masked by the intensive fresh and fruity wine aroma [ 111 ]. Even lower threshold concentrations (less than 0.5 μg L −1 ) have been observed in meager and light wines [ 112 , 114 ].…”

“…This fault is mentioned directly in the scoring system of some sensory wine competitions among the fundamental faults of wine. The organizers thus warn the assessors to take the ATA phenomenon seriously [ 111 , 117 ].…”

“…Olfactory perception of ATA and its connection with the AAP levels was investigated in Croatian wines by Alpeza et al [ 111 ]. Wines with the occurrence of ATA were evaluated by the sensory analysis by the methods of “100 points” and “Yes/No” and AAP analyses were done by GC-MS.…”