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It is well known that grape aromatic composition is directly correlated to the final wine quality. To determine this composition, a previous stage of selective extraction is necessary, since the aromatic compounds are found in very low concentrations in the grapes. Therefore, in this work, the thin film microextraction technique (TF-SPME) was optimized, for first time, with the aim to analyze the volatile composition of the grape musts. The results obtained with the two commercially available absorbent materials for TF-SPME, polydimethylsiloxane/carboxene (PDMS/CAR) and PDMS/divinylbenzene (PDMS/DVB), were optimized and compared. To carry out the optimization, a randomized factorial design was performed combining the following factors and levels: extraction mode (headspace (HS), or direct immersion (DI)), stirring speed (500 and 1000 rpm), extraction time (1, 3 and 6 h), and extraction temperature (20, 40 and 60 °C). After performing a principal component analysis (PCA) and an analysis of variance (ANOVA) multifactorial, it was concluded that the best conditions for TF-SPME with PDMS/CAR were: direct immersion (DI), 500 rpm, 6 h, and 20 °C, while for TF-SPME with PDMS/DVB no conditions were found that maximized the extraction of most compounds, therefore compromise conditions were chosen: headspace (HS), 500 rpm, 6 h, and 40 °C. Finally, the comparison between the results obtained with both absorbents indicated that the absorbent that extracted better the volatile compounds from the musts with the TF-SPME technique, was PDMS/CAR, under the conditions: direct immersion (DI), 500 rpm, 6 h, and 20 °C., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

The amino acid concentration assessment along grape ripening would provide valuable information regarding harvest scheduling, wine aroma potential and must nitrogen supplement addition. In this work the use of Visible (Vis) and near-infrared (NIR) spectroscopy to estimate the grape amino acid content along maturation on intact berries was investigated. Spectral data on two ranges (570-1000 and 1100-2100 nm) were acquired contactless from intact Grenache berries. A total of 22 free amino acids in 128 grape clusters were quantified by HPLC. Partial least squares was used to build calibration, cross validation and prediction models. The best performances (R 2 P ~ 0.60) were found for asparagine (SEP: 0.45 mg N/l), tyrosine (SEP: 0.33 mg N/l) and proline (SEP: 17.5 mg N/l) in the 570-1000 nm range, and for lysine (SEP: 0.44 mg N/l), tyrosine (SEP: 0.26 mg N/l), and proline (SEP: 15.54 mg N/l) in the 1100-2100 nm range. Remarkable models (R 2 P ~0.90, SEP~1.60 ºBrix, and RPD~3.79) were built for total soluble solids in both spectral ranges. Contactless, non-destructive spectroscopy could be an alternative to provide information about grape amino acids composition., (Copyright © 2019 Elsevier B.V. All rights reserved.)

A method has been developed to analyse the glycosidic aroma precursor of non aromatic red grapes in terms of glucose GG. Due to the matrix interferences, an extract free of glycosylated polyphenols (especially anthocyanins and flavonols) and free glucose has been prepared. Such interferences have been eliminated by combining the use of Oasis MCX SPE and Fehling reagent. The glycosyl aroma precursor's fraction was subjected to an acidic hydrolysis (pH 1, 100°C, 1h), where equimolecular proportions of glucose (glucose GG) were released from their respective aglycones and quantified HPLC-IR. Compared with methods that require detailed analysis of the volatile aglycones, this one is able to estimate with good reproducibility the potential aroma of grapes by the only measurement of glucose GG., (Copyright © 2011 Elsevier B.V. All rights reserved.)

The aim of this work was to study the variability of 36 Saccharomyces cerevisiae wild strains isolated from different grape varieties and from two very distant zones, located in Northern and Southern Italy. The strains were differentiated on the basis of parameters of technological interest, such as resistance to antimicrobial compounds frequently present in wine, and the production of volatile aromatic compounds (VOC), determined by SPME procedure in the experimental wines obtained by inoculated fermentations. The VOC profile allowed to differentiate the yeasts in function of isolation area: S. cerevisiae isolated from Southern Italy grapes were able to produce more volatile compounds than those from Northern Italy. The compounds synthesized by all the yeasts, besides the ethanol, were 3-methyl-1-butanol and ethyl acetate. The production of acids during the alcoholic fermentation was a characteristic of Southern yeast strains. The screening of S. cerevisiae strains for technological parameters, such as sulphur dioxide, copper and ethanol resistance or hydrogen sulphide production, revealed similar behaviour for sulphur dioxide resistance among Northern and Southern S. cerevisiae strains. Copper resistance and sulphur dioxide production were correlated to isolation area: S. cerevisiae "Northern" strains showed higher copper resistance and lowest hydrogen sulphide production than that exhibited from "Southern" strains.