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The potentiality of a Waveguide Vector Spectrometer combined with multivariate data analysis was explored in order to set up predictive models of the main quality parameters of vinegar samples. Gain and phase spectra were acquired from 1.6 to 2.7 GHz and were used to build Partial Least Squares regression models. Segmented cross validations evidenced good accuracies for all the explored qualitative parameters with coefficient of determination values up to 0.997 (dry matter content).

Exposure to dissolved oxygen during the winemaking process adversely affects the sensory properties of wines such as loss of colour, aromatic defects and increase of astringency. For decades the management of juice browning in enology has been managed by adding sulphur dioxide as a powerful antioxidant and antimicrobial agent. However, since sulfites are growingly rejected by consumers because of their chemical nature and known allergenic properties, developing biologically relevant alternatives is an expanding field in enology. Recently chitosan, an abundant biopolymer obtained by deacetylation of chitin from animal or vegetal sources, has been recommended as alternative fining agent in wines, showing antimicrobial, biodegradable and non-allergenic properties. Chitin derivatives also demonstrated metal chelating effects (which slower oxidation in wines), interacting with grape polyphenols such as caftaric acid (whose enzymatic oxidation results in excessive browning [1]), and inhibiting (+)-catechin oxidation in model white wines [2]. Using electron paramagnetic resonance (EPR) techniques involving nitrones spin traps and standard oxyradical generating systems, this study presents for the first time complementary facets of the antioxidant action of chitosan, including direct scavenging of hydroxyl radical (a highly oxidizing species formed during wine oxidation) and chelation of metals (iron and copper). Experiments were conducted in aqueous medium, wine matrix, and commercial white wines, and different chitosans were tested at concentrations (0.12 g/L) allowed by enology regulations. Altogether, EPR data support the preferential use of chitosan as a reliable alternative for the reduction of sulphur dioxide to maintain wine freshness.

BACKGROUND: The use of a grapevine-shoot extract (VIN) is being studied as an alternative to sulfur dioxide (SO2). VIN stabilizes anthocyanins and preserves polyphenolic compounds, and thus improves chromatic wine properties. In this study, selected aroma compounds (esters, C13-norisoprenoids, oxidation and vine-shoot-related compounds), sensory analysis and the olfactometric profile were determined in the wines treated with VIN at two concentrations. RESULTS: Treatment with VIN hardly modified the content of esters and oxidation-related compounds in the wines. However, the high β-damascenone and isoeugenol contents and the increase in astringency at tasting in VIN wines were noteworthy, as were some odorant zones. All these were established as VIN markers after the chemometric data analysis. CONCLUSION: These data revealed that only the lowest dose tested may be recommended as a suitable alternative to SO2. Although some aromatic properties of these wines may change, these changes are not considered to affect the quality of the wines negatively. These results are useful for wineries, which face having to discover the aroma-related processes in the challenge of producing SO2-free wines without detriment to their sensory properties. © 2018 Society of Chemical Industry.

Verdelho is a white-grape-vine, traditionally used in Madeira wine production, which grows well in the Granite Belt region of the Australian state of Queensland, where it usually originate dry white wines. In this work, a complete volatile characterisation of Verdelho wines from the 2012 vintage produced in the Granite Belt region was carried out. Volatile compounds were isolated by Solid Phase Extraction (SPE), and identified and quantified using Gas Chromatography-Mass Spectrometry analysis (GC-MS). At the same time, a corresponding sensory characterisation of this distinctive Australian wine style has been investigated, by subjecting the most characteristic wines to a sensory descriptive analysis. The chemical compounds that mostly contributed to the flavour of these Verdelho wines were related to fruity sweet notes (ethyl esters and acetates), grass notes (3-hexenol), floral aromas (2-phenylethanol and β-linalool) and cheesy aromas (fatty acids). The results from sensory analysis confirmed that all the Verdelho wines analysed were characterised by fruity aroma attributes, especially of “tree-fruit” and “rockmelon”, together with “herbaceous”, while some significant differences in the other sensory attributes were found between samples.

Chitosan is an additive used in the food industry thanks to its proven anti-microbial, chelating and anti-oxidant activities. In 2011, the EU inserted chitosan to the list of additives permitted for use in winemaking practices to stabilize proteins, for microbial control and for the reduction of contaminants and heavy metals. However, even today, there are few studies with regards to the antioxidant capacity of this molecule in matrices similar to wine. In this study the efficacy of chitosan, in controlling the oxidation of (+)-catechin in a synthetic white wine under notable oxidative conditions, was tested and compared to that of sulfur dioxide, glutathione and ascorbic acid. The formation of intermediate oxidation compounds was determined using chromatographic HPLC-DAD-MS analyses and spectrophotometry. The results showed that chitosan had a notable capacity to delay the oxidative degradation of (+)-catechin and that this phenomena can be the result of mechanisms that involve the chelation of metals, the absorption of intermediate molecules and an anti-radical activity. The presence of chitosan also contributed to limit the oxidation of the thiol components found in the model solutions tested in this study. Based on the results obtained it is possible to propose chitosan as a potential additive capable to complement or substitute sulfur dioxide in winemaking processes aimed at reducing the sulfite content of white wines.

Introduction: In wines, the presence of sulfur compounds is the resulting of several contributions among which yeast metabolism. The characterization of the starter Saccharomyces cerevisiae needs to be performed also taking into account this ability even if evaluated together with the overall metabolic profile. Results and Discussion: In this perspective, principal aim of this experimental research was the evaluation of the volatile profiles, throughout GC/MS technique coupled with solid phase microextraction, of wines obtained throughout the fermentation of 10 strains of S.cerevisiae. In addition, the production of sulfur compounds was further evaluated by using a gas-chromatograph coupled with a Flame Photometric Detector. Specifically, the 10 strains were inoculated in Trebbiano musts and the fermentations were monitored for 19 days. In the produced wines, volatile and sulfur compounds as well as amino acid concentrations were investigated. Also the physico-chemical characteristics of the wines and their electronic nose profiles were evaluated.

Ad eccezione delle occasioni in cui la presenza di ossigeno sia una pratica enologica desiderata (ad esempio, ossigenazione controllata dei vini rossi), nella grande maggioranza dei casi il contatto (involontario) dei vini con l’ossigeno si traduce in un peggioramento della qualità complessiva del prodotto. L’insieme dei fenomeni che presiedono all’evoluzione ossidativa dei vini è assai complesso. Questa complessità è dovuta, in primo luogo, alla presenza di un consistente numero di sostanze (endogene o aggiunte nel corso del processo produttivo) in grado di partecipare al processo di ossidazione, rendendone talvolta imprevedibili le fasi e l’entità complessiva. Sebbene utilizzata da oltre un secolo, ad esempio, solo negli ultimi 15 anni si sono definite con maggior esattezza le interazioni ed i meccanismi chimici coinvolti nell’attività antiossidante della SO2. Questa molecola, principale additivo utilizzato nella filiera enologica per il controllo delle ossidazioni, è in grado di esplicare la propria azione attraverso una serie di reazioni che coinvolgono, tra l’altro, a seconda della loro presenza nel mezzo, le sostanze fenoliche (gli o-difenoli), i metalli (soprattutto Cu+ e Fe++), l’acido ascorbico o il glutatione. D’altro canto, le caratteristiche allergeniche dell’anidride solforosa hanno stimolato i produttori verso la riduzione del suo uso in vinificazione e alimentato la ricerca di possibili alternative tecnologiche. In questa ottica, l’utilizzo dell’acido ascorbico ha fornito risultati contrastanti, spesso legati alla necessità della contemporanea presenza di adeguate quantità di anidride solforosa ad evitare fenomeni pro-ossidativi. L’uso di tannini idrolizzabili è una ulteriore opzione a disposizione degli enologi che vogliano limitare i problemi legati all’ossidazione dei vini. Il tannino di galla, in particolare, ha dimostrato di possedere una rilevante capacità antiradicalica, sebbene pochi siano gli studi riguardanti un suo utilizzo in condizioni assimilabili a quelle del vino. Questo lavoro si è proposto di indagare gli effetti della presenza di SO2, acido ascorbico e tannino di galla, da soli od in combinazione, sulla ossidazione di una soluzione modello contenente (+)-catechina. Per ciascuna tesi predisposta è stato valutato il consumo di ossigeno disciolto, l’imbrunimento e la cinetica del consumo di (+)-catechina. Allo stesso tempo, è stata valutata la progressiva formazione degli ioni xantilio, pigmenti responsabili dello sviluppo delle nuances gialle tipiche delle soluzioni sottoposte ad ossidazione. I possibili meccanismi ossidativi sono stati discussi alla luce dei risultati ottenuti.

L’affinamento in legno è una tecnica idonea alla produzione di vini di qualità. Il contatto con il legno, infatti, oltre a favorire la migrazione nel vino di sostanze aromatiche, permette la dissoluzione di quantità di ossigeno in grado di promuovere la stabilizzazione della sostanza colorante e l’evoluzione della componente tannica del prodotto. Per questi fenomeni, un ruolo rilevante è ricoperto dalle catechine, dalle procianidine oligomere e, più in generale, da tutti quei composti fenolici in grado di interagire con l’ossigeno. La presenza e l’evoluzione di questi polifenoli nei vini in fase di affinamento è funzione della dotazione iniziale del prodotto, dell’entità dei fenomeni ossidativi e della cessione da parte dell’essenza legnosa impiegata. Tradizionalmente, le specie legnose utilizzate per l’affinamento di vini e distillati appartengono al genere Quercus spp. Negli ultimi anni, però, altre specie di uso locale hanno suscitato l’interesse dei produttori, grazie ai minori costi o al positivo contributo sensoriale. In questo lavoro, dopo aver caratterizzato la frazione fenolica estraibile da legno di ciliegio (Prunus avium), si è valutata l’evoluzione dei composti fenolici non antocianici in vini rossi affinati per 4 mesi in barriques o fusti ottenuti con lo stesso tipo di legno. I risultati sono stati posti a confronto con quelli ottenuti con l’utilizzo di barriques di rovere. L’uso di legno di ciliegio è stato contraddistinto dalla presenza, nel vino, di alcuni flavoni che potrebbero considerarsi markers del trattamento.

Taking into account the new European Higher Education Area (EHEA), the internationalization and cooperation among different universities is an essential aspect to be developed. The new Agrifood Campus of International Excellence (CeiA3) of Andalusia provides the possibility to researchers and professional workers of the Agrifood sector of improving their training by means of different courses of specialization called “Technical Training Courses”. A group of professors from the University of Cádiz, with the cooperation of a foreign professor from the University of Bologna (Italy) developed one of these courses in the academic year 2011/2012, whose title was “Analysis of oenological products by means of advanced chromatographic techniques”, and it was focused on graduates and professional of the agricultural sector from any part of Andalusia. The length of the course was 35 hours, a part of it was taught in English. The main teaching objectives of this course were on the one hand, to develop lessons from a very practical point of view, avoiding the typical master class and to establish a close report with students. And on the other hand, to improve the training of researchers and professional workers, offering them the possibility of receiving a course in a different place from them, with the most exhaustive and comprehensive scientific material. The mobility of the students was finally achieved because a high percentage of them were external from the University of Cádiz. Moreover, as can be derived from a final questionnaire submitted to students, the obtained opinions of the course were excellent and all the students were very satisfied with both the scientific material provided and the practical teaching methodology. However, only with a low number of students (10), this methodology could be successfully carried out. Finally, during the development of the mentioned course, the different professors involved improved as well several adeptness or competences, that are included in the Grade titles and therefore are evaluated during the academic teaching activity. Examples of these competences can be the following: oral expression, work group, resolution of practical scientific problems or communication in a second language

L’affinamento in legno è una pratica utilizzata in enologia al fine di migliorare le caratteristiche organolettiche dei vini. Tra gli altri, uno dei fenomeni che concorre a questa evoluzione è legato alla stabilizzazione della componente antocianica attraverso una serie di reazioni di addizione e condensazione tra i pigmenti stessi ed alcuni dei composti presenti nei vini. Sebbene tradizionalmente questo processo sia condotto utilizzando fusti di rovere (francese o americano), negli ultimi anni è progressivamente cresciuto l’interesse verso l’uso di essenze legnose alternative, di minor costo o più vicine a specifiche tradizioni enologiche regionali. Lo scopo della presente ricerca è stato quello di porre a confronto l’evoluzione del colore e dei derivati antocianici in vini affinati in contenitori di rovere (225 L) e di ciliegio (225L e 1000L). I dati ottenuti dimostrano come le tesi affinate in ciliegio siano evolute in maniera più rapida, probabilmente a causa di una maggiore porosità del legno. Nonostante un tenore finale in antocianine monomere pari a circa 1/3 rispetto alle prove affinate in rovere, le tesi conservate in barriques di ciliegio mostravano tonalità ed intensità coloranti non dissimili da quelle ottenute in legno di rovere, grazie alla maggior presenza di derivati antocianici e di polimeri colorati. Le tesi hanno evidenziato, inoltre, differenze significative nella evoluzione delle antocianine acilate. L’uso di fusti di ciliegio da 1000L è apparso promuovere il miglior compromesso tra rapidità dei fenomeni di stabilizzazione del colore ed adeguato mantenimento del patrimonio antocianico endogeno.