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.

Two commercial enzyme preparations were used in the production of wine from the Croatian autochthonous red grape variety Plavac Mali in order to improve the extraction of polyphenolic components from grapes, chromatic parameters, and sensory quality. During two vintages, the conventional maceration without enzymes was compared with the maceration using products with different characteristics: pectinase with additional cellulase and hemicellulase activity and pectinase with inactive yeast cells. Both products affected polyphenolic extraction and colour parameters: intensity and hue, and ratio between the yellow, red, and blue colour in young wines (2 months after fermentation) and at the moment of bottling (9 months after fermentation). The correlation between anthocyanins and colour intensity was very strong. The expected reduction of quantitative chromatic parameters during aging was confirmed. Significantly better results were observed in wines produced with pectinase, in relation to all analysed physical and chemical parameters. The sensory analysis showed that wines produced with pure pectolytic enzymes were significantly better than those produced without the enzymes. A product of the combination of pectolytic enzymes and inactive yeast cells had a partial influence on the improvement of the phenolic and sensory quality. The overall quality was significantly more expressed in wines produced with pectolytic enzymes, especially in young wines.

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.

The purpose of this research was to determine the effect of commercial pectolytic enzymes on the anthocyanin composition, colour parameters and specific sensory atributes in young wines produced of Croatian autochthonous variety Babić. The maceration without commercial enzymes was compared with two different enzymes: pectinase with additional cellulase and hemicellulase activity (A) and the pectinase with inactive yeast cells (B), during two harvests. Both products had a positive effect on the anthocyanin content and composition, but with different intensities. The influence of enzymes was confirmed through the colour parameters; intensity, hue and the ratio between yellow, red and blue, depending on product. Young wines produced with pectinase enzyme were significantly better, for all parameters. The sensory analysis showed that wines produced with pectinase enzyme (product A) were significantly better than those produced without enzymes. The combination of pectolytic enzymes and inactive yeast cells (product B) had a partial positive effect on the anthocyanins, colour parameters and sensory quality during two harvests. The use of specific commercial pectolytic enzymes can be a good and beneficial technological treatment in production of Babić young wine, based on preliminary research. These data confirmed the need to carry out research prior to use in real production, to select and recommend certain commercial enzyme products, according to the particular grape variety and certain wine properties that want to be improved.

Wine sensory testing is carried out by assessors who are usually selected and prepared depending on the test type, and their skills may vary depending on various factors. Expert wine assessors should have superior sensory evaluation abilities, an expert grape and wine knowledge level but even more assessment competence. The aim of this research was to test the competencies of certified Croatian expert wine assessors using a less-familiar descriptive sensory methodology with no preliminary training. These assessors are highly educated in viticulture and/or enology and work in this sector. They have certified sensory skills and shorter or longer experience in sensory testing wines with Geographical indications. Twenty-three assessors participated in the study, and the results were segmented by gender and age. The testing was performed in a laboratory accredited by ISO/IEC 17025. Graševina and Zweigelt wines were tested, and two groups of attributes were analyzed (main quality attributes and specific aroma descriptors). Qualitative and quantitative statistics showed that expert wine assessors had a very similar approach in the choice of descriptors and the perception of their intensity. No difference was obtained in testing any attribute and descriptor, neither for any wine nor between segmented groups concerning age. A significant difference was observed only between women and men in their perception of the two specific aroma descriptors. The results confirmed that combining expert knowledge and experience based on professional education and continuous analytical work can replace a lack of experience in some less-familiar methods.