Reversed-phase high-performance liquid chromatography–fluorescence detection for the analysis of glutathione and its precursor γ-glutamyl cysteine in wines and model wines supplemented with oenological inactive dry yeast preparations

El pdf del artículo es la versión pre-print.A reversed-phase high-performance liquid chromatography-fluorescence detection methodology involving a pre-column derivatization procedure using 2,3-naphtalenedialdehyde in the presence of 5 and 0. 5 mM of dithiothreitol to determine total and reduced glutathione (GSH) and γ-glutamyl-cysteine (γ-glu-cys) in musts and wines has been set up and validated. The proposed method showed good linearity (R 2 >99% for reduced and total GSH, and R 2 >98% for γ-glu-cys) in synthetic wines, over a wide range of concentration (0-10 mg L -1). The limits of detection for reduced GSH in synthetic and real wines were almost the same (0. 13 and 0. 15 mg L -1, respectively) and slightly higher for γ-glu-cys (0. 24 mg L -1). The application of the method allowed knowing, for the first time, the amount of total and reduced GSH and γ-glu-cys released into synthetic wines by oenological preparations of commercial inactive dry yeast (IDY). In addition, the evolution of these three compounds during the winemaking and shelf life (0-9 months) of an industrially manufactured rosé wine supplemented with a GSH-enriched IDY showed that although GSH is effectively released from IDY, it is rapidly oxidized during alcoholic fermentation, contributing to the higher total GSH content determined in wines supplemented with GSH-enriched IDYs compared to control wines. © 2011 Springer Science+Business Media, LLC.IAO and JJRB acknowledge CAM and CSIC for their respective research grants. This work has been founded by PET2007-0134 project.Peer Reviewe

Targeted Metabolomic Analysis of Polyphenols with Antioxidant Activity in Sour Guava (Psidium friedrichsthalianum Nied.) Fruit

Psidium is a genus of tropical bushes belonging to the Myrtaceae family distributed in Central and South America. The polar extract of Psidium friedrichsthalianum Nied. was partitioned with ethyl ether, ethyl acetate, and n-butanol, and the total phenolic content and antioxidant activity were measured by Folin-Ciocalteu and ABTS assays, respectively. The ethyl acetate fraction exhibited both the highest phenolic content and antioxidant activity. Due to the complexity of this fraction, an analytical method for the comprehensive profiling of phenolic compounds was done by UPLC-ESI/QqQ in MRM (multiple reaction monitoring) mode. In this targeted analysis, 22 phenolic compounds were identified, among which several hydroxybenzoic, phenylacetic, and hydroxycinnamic acid derivatives were found. This is the first time that (+)-catechin, procyanidin B1, procyanidin B2, and (−)-epicatechin have been reported as constituents of sour guava. A fractionation by exclusion size, C18-column chromatography, and preparative RRLC (rapid resolution liquid chromatography) allowed us to confirm the presence of ellagic acid and isomeric procyanidins B, well-known bioactive compounds. The content of phenolic compounds in this fruit shows its potential for the development of functional foods

Feasibility and application of a retronasal aroma‐trapping device to study in vivo aroma release during the consumption of model wine‐derived beverages

New types of wine-derived beverages are now in the market. However, little is known about the impact of ingredient formulation on aroma release during consumption, which is directly linked to consumer preferences and liking. In this study, the optimization and validation of a retronasal aroma-trapping device (RATD) for the in vivo monitoring of aroma release was carried out. This device was applied to assess the impact of two main ingredients (sugar and ethanol) in these types of beverages on in vivo aroma release. Two aroma-trapping materials (Lichrolut and Tenax) were firstly assayed. Tenax provided higher recovery and lower intra- and inter-trap variability. In in vivo conditions, RATD provided an adequate linear range (R(2) > 0.91) between 0 and 50 mg L(−1) of aroma compounds. Differences in the total aroma release were observed in equally trained panelists. It was proven that the addition of sugar (up to 150 mg kg(−1)) did not have effect on aroma release, while ethanol (up to 40 mg L(−1)) enhanced the aroma release during drinking. The RATD is a useful tool to collect real in vivo data to extract reliable conclusions about the effect of beverage components on aroma release during consumption. The concentration of ethanol should be taken into consideration for the formulation of wine-derived beverages

Application of an in vivo ptr-tof-ms approach to determine differences in wine aroma release among wines spiked with different types of oenological tannins

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Role of saliva on wine aroma release by using in vitro static and dynamic headspace conditions

Unlike other food products, the number of studies regarding aroma release during wine consumption using in vitro or in vivo approaches is very scarce, and research on the role of different intra-oral factors (such as saliva), which might be involved in aroma release during wine drinking is still incipient (1). Although the relatively short-intra-oral period of consumption of liquid foods, could indicate a limited effect of saliva on aroma release, the formation of intra-oral (and pharyngeal) aroma depots (2), and the fact that natural swallowing of saliva is continuously performed, makes the idea that saliva might exert an important role in the perception of wine aroma during consumption perfectly viable. However, only a couple of studies with contradictory results have attempted to determine the role of saliva on wine aroma release (3, 4). The fact that aroma release has been monitored using different extraction methodologies (static vs. dynamic headspace conditions) and others factors such as differences in matrix composition (ethanol, non-volatile wine matrix components) could also explain these differences.Therefore, the objective of this work was to determine the role of saliva on wine aroma release by using both static and dynamic headspace conditions. To follow a systematic study, avoiding the influence of different factors other than those of interest in this work (saliva effect and wine type) both methodologies were applied to reconstituted wines (with different non-volatile wine matrix composition) and a synthetic wine (with no matrix effect) keeping the same concentration of ethanol and aroma compounds. In addition, two types of saliva (human and artificial) and control samples (with water) were used to better understand the different mechanisms that saliva might induce on the release of aroma compounds from wine. Results from this work showed that in static conditions, red wines were more affected than white and synthetic wines by saliva, specifically human saliva, which provoked a reduction in aroma release for most of the assayed aroma compounds independent of their chemical structure. The application of dynamic headspace conditions using a saliva bioreactor at two different sampling points (t=0 and t=10 min) corresponding with oral (25.5 ºC) and post-oral phases (36 ºC), showed a lesser effect of saliva than matrix composition and a high influence of temperature on aroma release. (1) Munoz-Gonzalez, C.; Rodriguez-Bencomo, J. J.; Moreno-Arribas, M. V.; Pozo-Bayon, M. A. Anal. Bioanal. Chem. 2011, 401, 1497-1512.(2) Munoz-Gonzalez, C.; Martin-Alvarez, P. J.; Victoria Moreno-Arribas, M.; Angeles Pozo-Bayon, M.A J. Agr. Food Chem. 2014, 62, 66-73. (3) Genovese, A.; Piombino, P.; Gambuti, A.; Moio, L. Food Chem. 2009, 114, 100-107.(4) Mitropoulou, A.; Hatzidimitriou, E.; Paraskevopoulou, A. Food Res. Int. 2011, 44, 1561-1570

Effect of using glutathione-enriched inactive dry yeast preparations on the phenolic composition of rosé Grenache wines during winemaking

Aim: To know the effect of the addition of a commercial glutathione-enriched Inactive Dry Yeast (G-IDY) oenological preparation on the phenolic profile and colour parameters of rosé Grenache wines. Methods and results: A Control wine (Cont-W) and a wine with the G-IDY preparation (G-IDY-W) were industrially manufactured. The evolution of the phenolic composition (anthocyanins and non-anthocyanins) and colour of both types of wines was evaluated during winemaking and their shelf-life (after 1, 2, 3 and 9 months of bottle aging). Results revealed that wines manufactured with the G-IDY preparation showed differences in both their phenolic composition and colour characteristics with respect to the control wines, particularly after 9 months of aging. These differences were more evident in the anthocyanin than in the non-anthocyanin compounds. Conclusions: The G-IDY wines showed a greater decrease of the anthocyanins from grape origin, probably due to the formation of anthocyanin-polysaccharide complexes, and a higher concentration of some anthocyanin-derived pigments. These changes can be related to the slower colour evolution determined in wines produced using G-IDY preparations. Significance and impact of the study: The addition of the G-IDY preparation during winemaking modifies the anthocyanin composition of the resulting wines, which seems to provoke a slower colour evolution during their shelf-life

Chromatography-Fluorescence detection for the analysis 2 of glutathione and its precursor γ-glutamyl cysteine in 3 wines and model wines supplemented with oenological 4 inactive dry yeast preparations 5

Abstract 22 A Reverse Phase-High Performance Liquid Chromatography-Fluorescence detection 23 (RP-HPLC-FL) methodology involving a pre-column derivatization procedure using 24 2,3-naphtalenedialdehyde (NAD) in presence of 5 and 0.5 mM of dithiothreitol (DTT) 25 to determine total and reduced glutathione (GSH) and γ-glutamyl-cysteine (γ-glu-cys) in 26 musts and wines has been set up and validated. The proposed method showed good 27 linearity (R 2 > 99 % for reduced and total GSH, and R 2 > 98 % for γ-glu-cys) in 28 synthetic wines, over a wide range of concentration (0-10 mg L -1 ). The limits of 29 detection (LODs) for reduced GSH in synthetic and real wines were almost the same 30 (0.13 and 0.15 mg L -1 respectively) and slightly higher for γ-glu-cys (0.24 mg L -1 ). The 31 application of the method allowed knowing for the first time, the amount of total and 32 reduced GSH and γ-glu-cys released into synthetic wines by oenological preparations of 33 commercial inactive dry yeast (IDY). In addition, the evolution of these three 34 compounds during the winemaking and shelf-life (0-9 months) of an industrially 35 manufactured rosé wine supplemented with a GSH enriched IDY showed that although 36 GSH is effectively released from IDY, it is rapidly oxidized during alcoholic 37 fermentation, contributing to the higher total GSH content determined in wines 38 supplemented with GSH enriched IDYs compared to control wines