Enhance Wine Production Potential by Using Fresh and Dried Red Grape and Blueberry Mixtures with Different Yeast Strains for Fermentation.

Red grapes and blueberries are known for their high content of bioactive compounds and antioxidant properties. In Mediterranean winemaking, traditional sun-drying can be replaced by controlled-airflow-chamber-drying, which provides better quality, higher phenolic content, and increased antioxidants. This study aimed to increase the sugar content and phenolic compounds of the must by drying the fruits to fifty per cent of their original moisture content. Two musts were prepared: the first one was prepared by combining fresh red grapes and dried blueberries (M1), while the other was created using dried red grapes and fresh blueberries (M2), followed by fermentation at 25 °C with M05 Mead and X5 yeast strains. The M2 must showed the highest levels of phenolic compounds, red color (A520), total anthocyanins, and antioxidant activity. During fermentation, the anthocyanin content increased mainly in the dried blueberry macerates, where it increased between 4- to 5.5-fold. More bioactive compounds were extracted from the wines produced using yeast inoculation despite the shorter maceration times. A sensory analysis demonstrated consumers' acceptance of the wines in terms of color, flavor, and aroma. In conclusion, the use of red grapes in the production of blueberry red wine proved to be effective, providing higher sugar and must yields, while the dried fruits improved the fermentable sugar content obtaining wines with an alcoholic content between 10 and 11% (v/v). The higher levels of bioactive compounds increased the antioxidant capacity of the resulting red fruit wines.

FaMYB123 interacts with FabHLH3 to regulate the late steps of anthocyanin and flavonol biosynthesis during ripening.

In this work, we identified and functionally characterized the strawberry (Fragaria × ananassa) R2R3 MYB transcription factor FaMYB123. As in most genes associated with organoleptic properties of ripe fruit, FaMYB123 expression is ripening-related, receptacle-specific, and antagonistically regulated by ABA and auxin. Knockdown of FaMYB123 expression by RNAi in ripe strawberry fruit receptacles downregulated the expression of enzymes involved in the late steps of anthocyanin/flavonoid biosynthesis. Transgenic fruits showed a parallel decrease in the contents of total anthocyanin and flavonoid, especially malonyl derivatives of pelargonidin and cyanidins. The decrease was concomitant with accumulation of proanthocyanin, propelargonidins, and other condensed tannins associated mainly with green receptacles. Potential coregulation between FaMYB123 and FaMYB10, which may act on different sets of genes for the enzymes involved in anthocyanin production, was explored. FaMYB123 and FabHLH3 were found to interact and to be involved in the transcriptional activation of FaMT1, a gene responsible for the malonylation of anthocyanin components during ripening. Taken together, these results demonstrate that FaMYB123 regulates the late steps of the flavonoid pathway in a specific manner. In this study, a new function for an R2R3 MYB transcription factor, regulating the expression of a gene that encodes a malonyltransferase, has been elucidated.

Influence of Fermentation Time on the Phenolic Compounds, Vitamin C, Color and Antioxidant Activity in the Winemaking Process of Blueberry (Vaccinium corymbosum) Wine Obtained by Maceration.

Flavonoid compounds, including anthocyanins and flavan-3-ol derivatives, total tannins, total vitamin C and resveratrol were analyzed by HPLC in blueberry fruits, their skin and pulp, as well as in wines produced from them. Two wines were elaborated, with different times of fermentation. The fruit analysis provided information on the distribution of bioactive compounds in the berries, showing that the skin had the highest concentrations of all compounds. The winemaking process needed a maceration stage to extract these compounds from skins to wine. This maceration process increased the concentration of all compounds and the antioxidant activity values measured by the DPPH assay, but long maceration times decreased the compounds and the antioxidant activity, due to the phenolic compounds that were involved in several reactions, such as polymerization, copigmentation, degradation, formation of pyranoanthocyanins and reactions between anthocyanins and tannins. The sensorial analysis of wines showed that partial fermentation wine had better characteristics than total fermentation wine, although both wines had a high acidity.

Comparison of physicochemical properties, amino acids, mineral elements, total phenolic compounds, and antioxidant capacity of Cuban fruit and rice wines.

Physicochemical characterization, amino acids contents, minerals composition, total phenolic compounds, and antioxidant capacity of Cuban wines from different raw materials were studied. The wines studied were grape wines, tropical fruit wines, and rice wines. Twenty-one amino acids were identified and quantified, being Asp and Glu detected in all wines. The highest concentration of total amino acid content was found in wines elaborated from Cimarrona grape subjected to maceration with grape skins, while the raisined mixture grape wine presented the lowest values, probably caused by the amino acid degradation during the dehydration process by sun exposure. Minerals quantified were range amount limits of acceptable according to the OIV recommendation. Total phenolic compounds and antioxidant capacity showed the greatest values in wine from roasting rice. No statistical separation could be clearly observed by multivariate principal component analysis; however, 3 wine groups could be defined taking account the scores on the PC1.

The influence of berry perforation on grape drying kinetics and total phenolic compounds.

BACKGROUND: Drying is one of the traditional methods used for the conservation of fruits. In recent years, different methods have been developed to obtain higher quality products. Chamber-drying methods with hot air at controlled temperature are reliable and easy to use. The effect of piercing the structure of grape berries on their drying time was studied experimentally during convective drying within a temperature range of 30-50 °C. Experimental moisture loss results were fitted to different mathematical models, evaluated for goodness of fit by comparing their respective R2 , χ2 , and root mean square error. RESULTS: The Midilli et al. model provided a better prediction to describe the drying of whole grapes than the other models evaluated. However, punched grapes showed a better fit for the two-term model at 30 and 40 °C, and the approximation of diffusion model at 50 °C. The values of effective moisture diffusivity fluctuated between 8.04 × 10-12 and 7.31 × 10-11  m2  s-1 . Activation energy was 56.49 and 54.43 kJ mol-1 for whole and punched grapes, respectively. All the drying processes produced an increase of total phenolic compounds and antioxidant activity in grapes, these increases being higher in whole grape drying. CONCLUSION: The drying of punched grapes was faster and the activation energy higher than with drying of whole grapes; however, whole grapes presented more total phenolic compounds and antioxidant activity. © 2019 Society of Chemical Industry.

Optimization and validation of a DHS-TD-GC-MS method to wineomics studies.

A dynamic headspace sorptive extraction (DHS) combined with thermal desorption (TD) and coupled with gas chromatography-mass spectrometry (GC/MS) was developed for the determination of forty-four volatile aroma metabolites (VAMs) which describe aroma fingerprints of wines. The response surface methodology (RSM) and a central composite design (CCD) was used to obtain the optimal values for the experimental extraction variables, and the results were assessed by an analysis of variance (ANOVA) and a principal component analysis (PCA). The VAMs exhibited optimal extraction with the high levels of salt concentration (1.5 g NaCl) and using an extraction temperature of 40 °C during 10 min, and a subsequent purge volume of 300 mL. Subsequently, the calibration curves were created for the quantification of each VAMs with seven levels of concentration obtaining a correlation coefficients (R2) above 0.9900 for all of them. The proposed method was successfully validated and showed good precision and accuracy values for all VAMs. Lastly, the method was applied to quantify VAMs, responsible for the aroma fingerprints of white and red wines, from different Denomination of Origin.

Chemical and morphological characterization of Chardonnay and Gewürztraminer grapes and changes during chamber-drying under controlled conditions.

In this work, the morphological and chemical properties of Chardonnay and Gewürztraminer aromatic grapes (northern Spain) have been studied with the aim to assess their response to chamber-drying under controlled conditions and compare it with that of Pedro Ximenez grapes (southern Spain). Morphological characteristics, such as weight, size and roundness, and other of the skin such as thickness, enabled discrimination of the two types of grapes varieties. Changes in browning index, colour, antioxidant activity, aroma compounds determined by GC-MS and flavan-3-ols and flavonols concentrations determined by HPLC-DAD were studied during drying. Based on the results, Chardonnay and Gewürztraminer grapes contained increased amounts of flavan-3-ol derivatives, which are the greatest contributors to polymerization and condensation reactions. Also, their smaller size resulted in faster drying and leads to sugary musts that were lighter-coloured, less brown and more aromatic than Pedro Ximenez grapes.

Optimization and validation of an automated DHS-TD-GC-MS method for the determination of aromatic esters in sweet wines.

A dynamic headspace sorptive extraction (DHS) combined with thermal desorption (TD) and coupled with gas chromatography-mass spectrometry (GC/MS) was developed for the determination of 11 esters which contribute to the fruity aroma in sweet wines. A full factorial (4 factors, 2 level) experiment design was used to optimize the extraction conditions and the results were evaluated by multiple linear regression (MLR) and principal component analysis (PCA). The esters showed optimal extraction using an extraction temperature of 30°C during 20 min, and a subsequent purge volume of 300 mL and dry volume of 50 mL. Afterwards, quantification was achieved using calibration curves constructed for each ester with linear regression equations having correlation coefficients (R(2)) ranging from 0.9894 to 0.9981. The proposed method was successfully validated and showed good intermediate precision, repeatability and accuracy values for all the monitored compounds. Finally, the method was applied to quantify esters, with fruity aromatic notes, of sweet white and red wines, elaborated with different winemaking processes.

Influence of bottle storage time on colour, phenolic composition and sensory properties of sweet red wines.

Changes in colour and phenolic composition in sweet red wines made from Merlot, Syrah and Tempranillo grapes were studied in order to assess the influence of bottle storage over a period of 12months. For this purpose, wine colour parameters, sensory analysis and concentrations of monomeric anthocyanins, pyranoanthocyanins, methylmethine-mediated condensation adducts, flavan3-ol derivatives and flavonols were measured. Hue increased and red colours decreased with the storage time, particularly over the first 3months. The concentrations of low molecular weight flavan-3-ol derivatives decreased with time due to the effect of their conversion into tannins of high molecular weight. In addition, the glycosylated flavonols decreased through hydrolysis to give the corresponding aglycones. Overall, the concentration of phenolic compounds decreased markedly with storage time, whereas the antioxidant activity in the wines remained constant throughout. A panel of expert tasters judged the colour, aroma and flavour of all initial and final wines to be acceptable.

Anthocyanin evolution and color changes in red grapes during their chamber drying.

In this work, the effects of chamber drying under controlled temperature and moisture conditions on three varieties of red grapes (Merlot, Tempranillo, and Syrah) cultivated in warm areas in southern Spain were studied. This drying was made with a view to their use in the production of sweet red wines. Analyses included color parameters, browning index, and anthocyanin concentrations measured by HPLC-DAD/MS. Based on the results, drying increases color and the concentration of these phenolic compounds by the effect of dehydration of the berries and diffusion of the colored compounds from the skin to the pulp due to the structural alterations in their skin. In addition, drying increased the browning index (OD 420), although less markedly than OD 520, as well as decreased the hue (OD 420/OD 520). The musts exhibited the typical color of red wines and a marked darkness by the effect of their low lightness (L* < 20 CIELAB units). Although the sugar content of the musts obtained at 24 h of drying was less, these musts were better to use in the vinification process, even without the maceration step as a result of their higher anthocyanin content, less browning, and darker color. To increase the content of the high-molecular weight compounds and anthocyanin derivatives, more raisining time could be required.

Formation of vitisins and anthocyanin-flavanol adducts during red grape drying.

This study evaluated the formation of anthocyanin-derived compounds during the production of sweet red wines from Merlot and Syrah grapes previously chamber-dried under controlled-temperature conditions. The musts from both grape varieties were found to contain pelargonidin-3-glucoside throughout the vinification process. Besides, HPLC-DAD-MS revealed the presence of pyranoanthocyanins in unfermented musts from the raisins. These compounds are adducts resulting from the cycloaddition of pyruvic acid (type A vitisins) and acetaldehyde (type B vitisins) to anthocyanin molecules. The analyses additionally revealed the presence of products of the condensation via a methylmethine bridge between anthocyanins and (epi)catechin, which requires the presence of acetaldehyde. The absence of pyruvic acid, acetaldehyde, and ethanol in the musts from fresh grapes and their presence in those from dried grapes support the idea that these compounds result from enzymatic transformations because the vinification of the musts involves no alcoholic fermentation. The drying process alters the permeability of grape membranes by the lipoxygenase activation effect (LOX), a switch to an anaerobic metabolism and the resulting triggering of the alcohol dehydrogenase enzyme (ADH). The activation of these and several other enzymes confirmed the occurrence of enzymatic transformations and the formation of vitisin A, acetylvitisin A, and the B vitisins of malvidin-3-glucoside, peonidin-3-glucoside, peonidin-3-acetylglucoside, and malvidin-3-acetylglucoside, as well as the adducts Pn-3-glc-methylmethine(epi)catechin, Mv-3-glc-methylmethine(epi) catechin, and Mv-3-acetylmethylmethine(epi)catechin.

Changes in hydrophilic and lipophilic antioxidant activity in relation to their phenolic composition during the chamber drying of red grapes at a controlled temperature.

The purpose of this work was to study the variation of phenol compounds, as measured by HPLC, during the chamber drying under controlled temperature conditions of red grapes of the Merlot and Tempranillo varieties in relation to antioxidant activity. Both lipophilic and hydrophilic antioxidant activities in these grapes increased during the drying process; the former was measured via proton transfer in the coupled oxidation reaction between linoleic acid and ß-carotene, and the second via electron transfer in the DPPH assay. The hydrophilic component was invariably greater in Tempranillo grapes, and so was the lipophilic component in Merlot grapes. Only the increase in hydrophilic antioxidant activity obtained a significant correlation with the phenolic compounds during the drying process. However, based on the phenolic fraction analysis, this result was primarily due to phenolic polymers and, to a lesser extent, also to phenolic acids, flavans, and some flavonols and anthocyans.

Changes of ochratoxin A in grapes inoculated with Aspergillus carbonarius and subjected to chamber-drying under controlled conditions.

The production pattern for ochratoxin A in grapes inoculated with Aspergillus carbonarius and changes in its concentration during raisining of Merlot, Syrah, Tempranillo, and Cabernet Sauvignon red grapes and Pedro Ximenez white grape were studied. Grapes were chamber-dried under controlled temperature and humidity conditions, with and without dipping pretreatments in alkaline emulsions of olive oil or ethyl oleate. Based on the results for the grapes that developed the fungus (Merlot and Pedro Ximenez), a temperature of 50 °C in the absence of dipping stopped ochratoxin A production and even degraded part of the toxin already formed. Both dipping pretreatments facilitated removal of the toxin and led to its virtually complete disappearance. However, dipping in the ethyl oleate emulsion caused substantial changes in the sensory characters of the musts obtained from the raisins, so it should be avoided to ensure the expected quality in the sweet wines elaborated from them.

Drying of Pedro Ximenez grapes in chamber at controlled temperature and with dipping pretreatments. Changes in the color fraction.

The drying of Pedro Ximenez grapes in chamber at a controlled temperature of 40 or 50 degrees C is studied. Compared to traditional sun-drying, the chamber-drying shortened the drying time by about 40% at 50 degrees C. In color terms, the musts obtained from grapes dried at 50 degrees C were closer in CIELab coordinates to those obtained by sun-dried grapes, with similar h(ab) values and slightly lower L* and C(ab)*. To shorten further the drying times at 50 degrees C, the grapes were dipped in olive oil or ethyl oleate emulsions containing potassium carbonate. The ethyl oleate pretreatment shortened additionally the drying time by about 25%, providing musts with chroma, lightness, and hue similar to those without grape pretreatment. In general, except for the phenolic compounds corresponding to the drying with ethyl oleate pretreatment, most of these compounds in the remainding conditions studied increased to a lesser extent than expected because of water losses of the grapes during drying, revealing degradation reactions.

Changes in color and phenolic compounds during the raisining of grape cv. Pedro Ximenez.

Changes in color parameters and phenolic compounds during the sun-drying grape raisining of cv. Pedro Ximenez to obtain sweet wines are studied. Browning increases during the process as a result of the contribution to a greater extent of the low and medium molecular size polymers than the high molecular size polymers. Raisining decreases hue and lightness and increases chroma, all measured as CIELab parameters, indicating a color change to dark reddish hues that is also preferentially due to low and medium molecular size polymers. Most of the phenols studied increase in concentration during raisining, essentially through the concentration effect resulting from the loss of water in the grapes. The concentration changes, however, are comparatively small for hydroxycinnamic esters and flavan-3-ol derivatives, suggesting that these phenolic fractions undergo predominantly oxidative degradation reactions by enzymatic pathways, contributing strongly to the browning of grapes.