Impact of Sequential Inoculation with the Non-Saccharomyces T. delbrueckii and M. pulcherrima Combined with Saccharomyces cerevisiae Strains on Chemicals and Sensory Profile of Rosé Wines.

Controlled inoculations of non-Saccharomyces yeasts are becoming increasingly used to produce high-quality wines due to their enological potential. In this study, we evaluated the impact of sequential inoculation with the commercial non-Saccharomyces yeasts (Torulaspora delbrueckii and Metschnikowia pulcherrima) in combination with Saccharomyces cerevisiae on the chemical and sensory profile of rosé wines. Sequential inoculation with T. delbrueckii produced wines with an overall reduction in esters, mainly explained by the lower concentrations of ethyl esters of medium-chain fatty acids and isoamyl acetate. The lower ester concentrations of these wines were related to a reduction in fruity descriptors. An increase was observed, however, in other minor esters such as cinnamates and ethyl esters of branched acids. Zinc, ethyl isobutyrate, and ethyl dihydrocinnamate were selected as potential markers for this fermentation strategy. Sequential inoculation with M. pulcherrima resulted in rosé wines with an enhanced ester profile, reduced acetaldehyde, and increased anthocyans and tannins. Compared to the control wines fermented with S. cerevisiae, the changes observed in these wines were far subtler, especially for the volatile profile, sensory characteristics, and color parameters, with isobutyl hexanoate and isoamyl butyrate being selected as potential markers.

Multivariate optimization of headspace solid-phase microextraction coupled to gas chromatography-mass spectrometry for the analysis of terpenoids in sparkling wines.

A headspace solid-phase microextraction coupled to gas-chromatography and mass spectrometry (HS-SPME-GC-MS) was developed and validated for the determination of 26 terpenes in sparkling wines. The use of a Box-Behnken experimental design, together with the desirability function D, allowed the extraction conditions of the method to be optimized. The optimal extraction conditions were found at a dilution ratio of 2:3, the addition of 3.5 g of NaCl, an extraction temperature of 46 °C and an extraction time of 52 min, using the DVB/CAR/PDMS fibre. Afterwards, the analytical method was successfully validated in terms of linearity, matrix effect, limit of detection and quantification, precision and accuracy. To test the developed method, 35 commercial sparkling wines from different grape varieties, geographical regions and ageing times were analysed and their terpenoid profile was monitored. The use of multivariate statistical tools made it possible to highlight differences in the samples related to the terpene profile. Finally, the most important compounds involved in the discrimination of the samples were identified by means of iterative variable selection procedures.

A critical evaluation of the use of gas chromatography- and high performance liquid chromatography-mass spectrometry techniques for the analysis of microbial metabolites in human urine after consumption of orange juice.

The present study compared and validated two analytical methods, HPLC-HRMS, and GC-MS using MSTFA as derivatization agent, for the analysis of microbiota-derived phenolic acids and aromatic compounds accumulating in urine, collected over a 24 h period after the consumption of 500 mL of orange juice. In addition, purification procedures using SDB-L and HLB solid phase cartridges were compared when HPLC-HRMS technique was used. Both HPLC-HRMS and GC-MS methodologies were successfully validated in terms of specificity, sensitivity, limit of detection and quantification, recovery and matrix effects. HPLC-HRMS, unlike GC-MS, does not require sample derivatization prior to analysis. GC-MS was not suitable for the analysis of phenolic sulfate and glucuronide metabolites because of their lack of volatility. These phase II metabolites could, however, be analysed by HPLC-HRMS which, as a consequence, provided more detailed and complete information on the phenolic compounds derived from microbiota-mediated degradation of orange juice (poly)phenols. Furthermore, the use of SDB-L and HLB cartridges for sample purification prior to HPLC-HRMS analysis is suitable for free phenolics and glucuronide metabolites but not sulfate derivatives. These findings highlight that the use of an inappropriate analytical protocol can adversely affect studies on the bioavailability of dietary (poly)phenols in which microbiota-derived phenolic catabolites play an important role.

Sulfur free red wines through the use of grapevine shoots: Impact on the wine quality.

Following a preliminary study to determine the possibility of using a grapevine shoot extract (VIN) as a sustainable alternative to sulfur dioxide (SO2), in this study, the chromatic features, phenolic composition, and sensory analysis of wines treated with VIN at two concentrations were studied during storage in bottle for the first time. The highest differences were found in phenolic compounds after 12months of storage in bottle. The VIN wines had a low content of free anthocyanins and were high in vinyl-pyranoanthocyanins, and B-type vitisins. Consequently, they showed better chromatic characteristics. Moreover VIN, especially at high dose, preserved non-anthocyanin phenolic compounds better than SO2. However, at this high dose some organoleptic properties were affected. VIN, when used at a low dose, is able to preserve wine composition without loss of quality.

The influence of pre-fermentative maceration and ageing factors on ester profile and marker determination of Pedro Ximenez sparkling wines.

The influence of pre-fermentative maceration and ageing factors on the ester profiles of Pedro Ximenez sparkling wines was evaluated. The pre-fermentative maceration consisted of the skin-maceration of musts at 10°C for 6h. The sparkling wines were produced following the Champenoise method. Samples were monitored at 3, 6 and 9months of ageing on lees. Sparkling wines with pre-fermentative maceration displayed higher contents of ethyl esters of branched acids and cinnamates. Meanwhile, those without maceration showed higher levels of ethyl esters of fatty acids and higher alcohol acetates. The study of statistical interactions elucidated different hydrolytic kinetics and developments in higher alcohol acetates and ethyl esters of branched acids during ageing. The application of a dual criterion based on univariate (ANOVA) and multivariate analyses (OPLS-DA) allowed us to identify new potential volatile markers related to pre-fermentative maceration and ageing time, reported for the first time in sparkling wines.

Quantitative Profiling of Ester Compounds Using HS-SPME-GC-MS and Chemometrics for Assessing Volatile Markers of the Second Fermentation in Bottle.

A quantitative approach using HS-SPME-GC-MS was performed to investigate the ester changes related to the second fermentation in bottle. The contribution of the type of base wine to the final wine style is detailed. Furthermore, a discriminant model was developed based on ester changes according to the second fermentation (with 100% sensitivity and specificity values). The application of a double-check criteria according to univariate and multivariate analyses allowed the identification of potential volatile markers related to the second fermentation. Some of them presented a synthesis-ratio around 3-fold higher after this period and they are known to play a key role in wine aroma. Up to date, this is the first study reporting the role of esters as markers of the second fermentation. The methodology described in this study confirmed its suitability for the wine aroma field. The results contribute to enhance our understanding of this fermentative step.

Assessing a traceability technique in fresh oranges (Citrus sinensis L. Osbeck) with an HS-SPME-GC-MS method. Towards a volatile characterisation of organic oranges.

A targeted approach using HS-SPME-GC-MS was performed to compare flavour compounds of 'Navelina' and 'Salustiana' orange cultivars from organic and conventional management systems. Both varieties of conventional oranges showed higher content of ester compounds. On the other hand, higher content of some compounds related with the geranyl-diphosphate pathway (neryl and geranyl acetates) and some terpenoids were found in the organic samples. Furthermore, the partial least square discriminant analysis (PLS-DA) achieved an effective classification for oranges based on the farming system using their volatile profiles (90 and 100% correct classification). To our knowledge, it is the first time that a comparative study dealing with farming systems and orange aroma profile has been performed. These new insights, taking into account local databases, cultivars and advanced analytical tools, highlight the potential of volatile composition for organic orange discrimination.

Grapevine-shoot stilbene extract as a preservative in red wine.

This paper reports the use of a grapevine-shoot stilbene extract (Vineatrol®) as a preservative in red wine. Its effectiveness to preserve red wine quality under two different winemaking systems (traditional and Ganimede) was studied at bottling and after twelve months of storage in bottle. Enological parameters, color related parameters, volatile composition, sensory analysis and olfactometric profile were evaluated. At bottling wines treated with Vineatrol showed higher color related parameters and higher score in sensory analysis than those treated with SO2. The use of SO2 increased ester and alcohol volatile compounds in relation to the use of Vineatrol. Wine olfactometric profile was modified by Vineatrol addition. Two new odorant zones with high modified frequency appeared in wines treated with Vineatrol. After 12months of storage in bottle, wines treated with Vineatrol showed parameters related to oxidation. The weak point of the process seemed to be the evolution during the storage in bottle.

Effect of Organic and Conventional Management on Bio-Functional Quality of Thirteen Plum Cultivars (Prunus salicina Lindl.).

In this study, thirteen Japanese plum cultivars (Prunus salicina Lindl.) grown under conventional and organic conditions were compared to evaluate the influence of the culture system on bioactive compounds. Their organic acids content (malic, citric, tartaric, succinic, shikimic, ascorbic and fumaric acid), total polyphenols, total anthocyanins, total carotenoids and antioxidant capacity (FRAP, ABTS) were evaluated. The study was performed during two consecutive seasons (2012 and 2013) in two experimental orchards located at the IFAPA centre Las Torres-Tomejil (Seville, SW Spain). The culture system affected all the studied parameters except for total carotenoid content. The organic plums had significantly higher polyphenol and anthocyanin concentrations and a greater antioxidant capacity. Additionally, significant differences between cultivars were also found. 'Showtime' and 'Friar' were the cultivars with the highest polyphenol concentration and antioxidant capacity. 'Black Amber' had the highest anthocyanin content and 'Larry Ann' and 'Songold' the highest carotenoid content. 'Sapphire' and 'Black amber' were the cultivars with the highest concentration of ascorbic acid. Our results showed a strong year effect. In conclusion, organic management had an impact on the production of phytochemical compounds in plums.