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.

Due to possible various physiological errors in sensory testing, regardless of knowledge and experience, it is necessary to control the results and assessors. This paper aims the possibility of some statistical tools based on laboratory control charts to monitor assessors in wine sensory analyses done in the certification procedure. The data of control charts and reliable results were processed, and individually the results of "100 points" and "Yes/No" methods. The possibility of checking the consistency and concordance of the assessors using wine faults descriptors is also presented. It has been observed that the Chi-square test and some graphical statistics, such as scatter with correlation analysis, can be a good tool in assessors monitoring. The results of sensory analyses affect the wine declaring, and therefore, continued development of technical conditions and tools in the monitoring of assessor's performance is expected to reduce subjectivity and potential errors.

Miris vina je kompleksna i kreativna referenca kakvoće i vrlo važan čimbenik u izboru vina. Nepoželjni mirisi stoga nisu prihvatljivi, a neki mogu biti i štetni za zdravlje. Posljednjih dvadesetak godina posebice se bilježi porast kompleksnih neugodnih sumpornih mirisa. Cilj ovog rada bio je analizirati učestalost pojave nepoželjnih mirisa u hrvatskim vinima prije stavljanja na tržište. U analizi su korišteni rezultati senzornih ispitivanja vina za razdoblje 2008.-2019., za oksidaciju, octikavost, etil acetat, sumporovodik i merkaptanske mirise, kao glavne probleme mirisa. Uočen je trend pada udjela loših uzoraka u odnosu na čitavo promatrano razdoblje. Dodatna analiza provedena je za sumporne nepoželjne mirise, za razdoblje 2014.-2019., pri čemu je utvrđen porast problema reduktivnih mirisa općenito, a posebno izražen porast mirisa merkaptanskih spojeva. Obzirom na brojnost i složenost čimbenika kakvoće, ovi rezultati upućuju na potrebu kontinuirane kontrole proizvodnje i traženja načina za sprečavanje nastanka nepoželjnih mirisa vina.

“Portugizac Mlado vino” is a local red wine with Protected designation of origin and Traditional term, and it is usually consumed very soon after alcoholic fermentation as a young wine. The maturation and aging of the wine affect the aroma composition, which is generally not pronounced and specific in the case of most red wines, but, as a sensory property, it is important for the perception of quality and consumer choice. The objective of this work was to analyze the most important aroma compounds of esters and higher alcohols, with the unpleasant volatile phenols too, in “Portugizac” wines, related to aging. The 9 young wines “Portugizac”, PDO “Plešivica” were analyzed after 3 and after 15 months of bottle storage at 16 ºC. Ethyl esters of butanoic and hexanoic acid along with isoamyl acetate are considered to be the most important esters in the fruity aroma of wine, and their concentrations in all analyzed “Portugizac” young wine samples were higher than their perception thresholds. The concentration of ethyl acetate was in the range 30-123 mg/L. The concentrations of ethyl esters of octanoic and decanoic acid, as well as 2-phenyl ethyl acetate and diethyl succinate in all analyzed wines, were lower than their perception thresholds. The concentrations of higher alcohols were much higher than their perception threshold. Bottle storage significantly affected the concentrations of analyzed compounds; after 15 months, the concentrations of acetate and ethyl esters (except ethyl acetate and diethyl succinate), as well as terpene (linalool), decreased, while higher alcohols and ethyl phenols slightly increased if compared to three months. In general, the compounds responsible for the desired fresh, fruity aroma tones were altered in an undesirable manner, while, undesirable compounds of 4-ethyl-phenol and 4-ethyl-quaiacol, which were not present in young wines, were detected in aged wines. It can be concluded that the bottle aging affects the aroma profile, undesirable changes were more pronounced than positive ones and therefore the consumption of young wine “Portugizac” might be more sensory attractive.