Monastrell Grapes Research Articles

Extraction and Partial Purification of β-Galactosidase from Grape Berry Skin (Vitis viniferaL.) with Triton X-114

Monastrell grape skins show a high percentage of galactose, likely due to low β-galactosidase activity. Little is known about the characteristics of this enzyme. A simple method to extract and partially purify β-galactosidase from grape berry skin is presented. The kinetic properties of this enzyme are comparable to those of β-galactosidase from other fruits. In this method Triton X-114 (a non-ionic detergent) has a double effect: solubilizing skin components to liberate the enzyme and removing most phenols and hydrophobic proteins, giving rise to a 56-fold increase in specific activity. The method proposed may be useful to easily extract and partially purify this enzyme during grape berry ripening.

Application and comparison of four selected procedures for the isolation of cell-wall material from the skin of grapes cv. Monastrell

In order to choose an appropriate cell-wall material (CWM) isolation procedure in grapes cv. Monastrell, four different standard procedures have been tested, and a comparison made of the amount of cell-wall material obtained, its composition and morphology. The CWM was isolated as the 70% ethanol insoluble residue (de Vries method), as the absolute ethanol insoluble residue filtered sequentially through nylon mesh (Nunan method), as the insoluble residue in sodium deoxycholate–phenol–acetic acid–water (Selvendran method) and as the N-[2-hydroxyethyl]-piperazine-N′-2-ethanesulfonic acid (HEPES) insoluble residue (Vidal method). All extractions were done in triplicate and the efficiency of the extractive procedure established. Carbohydrates, proteins, and phenolic compounds were analysed, as the main constituents of CWM. The morphology of the isolated CWM was visualized by scanning electron microscopy (SEM). The Selvendran method had the highest efficiency, while the Nunan method had the lower one. Regarding the carbohydrates composition, the four different CWM were rich in uronic acids and glucose, together with varying amounts of arabinose, xylose, mannose and galactose. The Selvendran method had the lower value of total carbohydrates and the CWM shows more plasmatic membrane impurities in SEM images. The chemical results of the Vidal and de Vries methods were quite similar, but the Vidal method was more time consuming than the de Vries method. According to the results, the de Vries method was chosen to produce a representative cell-wall material fraction from Monastrell grapes skin.

Study of the Evolution of Nitrogen Compounds during Grape Ripening. Application to Differentiate Grape Varieties and Cultivated Systems

The aim of this work was to study the evolution of amino acids and ammonium during grape ripening and to evaluate its application to differentiate grape varieties and cultivated systems (organic and nonorganic). For this purpose, Monastrell, Syrah, Merlot, and Petit Verdot grapes produced using conventional agriculture and Monastrell grape cultivated using organic agriculture, collected during two consecutive harvests at different stages of ripening, were studied. These years of harvest were very different climatic years; even so, the grape varieties presented similar qualitative compositions. Therefore, the percentage of amino acids at harvest moment allowed differentiation of grapes according to variety and cultivated system, regardless of the year. The nitrogen composition could allow estimation of the fermentative aroma potential of grapes. Thus, Syrah was the grape with the greatest aroma potential at harvest. Monastrell nonorganic grape had a concentration of nitrogen compounds superior to that of Monastrell organic grape. In Monastrell, Syrah, and Merlot, traditional varieties in the area, the highest concentration of nitrogen compounds coincided with the highest degrees Baume/total acidity ratio and color index during 2007. Consequently, technological and phenolic maturity of these grape varieties coincided with the maximum composition of nitrogen compounds. However, in 2008, this did not happen because grape ripening was irregular as a consequence of different climatological conditions.

Characterisation of the main enzymatic activities present in six commercial macerating enzymes and their effects on extracting colour during winemaking of Monastrell grapes

SummaryNumerous studies have reported on the use of enzymes in wineries to facilitate the extraction of grape phenolics and to aid colour stability, although no clear conclusions were reached. Information concerning the enzymatic activities of industrial preparations is very difficult to obtain despite its importance. The aim of this work was to characterise and quantify the activities of six macerating enzyme preparations to optimise their use, and to study their effect on the chromatic characteristics of a Monastrell wine. The results indicate that differences exist in the type of enzymatic activities present in the preparations and in their concentration. The chromatic characteristics of the resulting wines, both at the end of alcoholic fermentation and after 12 months of storage in stainless steel tanks, showed differences with the use of the different maceration enzymes when comparing with control wine, although very little differences were observed between the different enzyme treatments. The enzyme‐treated wines showed, at the end of alcoholic fermentation, a higher OD280 and tannin content, and after 12 months, a higher colour intensity too. The main effect of all the preparations was an increase in the total phenol content, probably by facilitating the release of skin tannins.

Changes in skin cell wall composition during the maturation of four premium wine grape varieties

AbstractBACKGROUND: Grape skin cell walls form a barrier against the diffusion of colour. The colour of red wines is mainly due to anthocyanins, although their concentration in wine is not always correlated with the anthocyanin content of grape skins. The cell wall composition changes during fruit ripening, so it was thought that a study of the ripening behaviour of four premium varieties might provide information on how the composition changes during ripening and explain the technological differences.RESULTS: The largest quantities of skin cell wall material (CWM) were isolated from Monastrell grapes, probably owing to the greater number of cell layers they contain and the thicker cell walls. During ripening, a loss of skin CWM (e.g. 120–60 and 65–45 mg CWM g−1 fresh skin for Monastrell J and Cabernet Sauvignon respectively) and galactose (e.g. 36–20 and 55–30 mg g−1 CWM for Cabernet Sauvignon and Monastrell J respectively) was observed, together with a decrease in the degree of pectin methylation and acetylation, except in Syrah, in which pectin methylation remained unchanged. These changes were accompanied by the accumulation of glucose, while other neutral sugars showed no significant variations. A correlation was found between the degree of ripening and those constituents changing in the grape skin cell wall.CONCLUSION: The cell wall composition differs sufficiently between grape varieties to allow discrimination between them. Ripening was associated with a decrease in the quantity of CWM and galactose in the cell walls. Monastrell showed the largest quantities of both throughout ripening. The differences observed between Monastrell and the other varieties would explain the technological differences between them. Copyright © 2007 Society of Chemical Industry

Differences in morphology and composition of skin and pulp cell walls from grapes (Vitis vinifera L.): technological implications

The morphology and composition of skin and pulp cell walls of four premium red wine grape (Vitis vinifera L.) varieties were studied to determine whether the technological differences observed in previous studies between the four different varieties during the winemaking process (especially, the anthocyanin extractability) could be partly explained by their respective cell wall compositions. Monastrell grapes showed the highest amount of cell wall material in their skins (55–57 mg cell wall/g skin), while Syrah showed the largest amount of cell wall material in the pulp (5.1 mg cell wall/g pulp). The highest percentage of galactose and cellulosic glucose in skin and pulp cell walls was also found in Monastrell grapes. The cell wall composition of Monastrell grapes, together with their morphology, suggests that the firmer pulp and skin are responsible for the difficulties this variety shows for anthocyanin extraction (extractability index varying from 37 to 60). As cell wall composition may be modulated by the action of enzymes, the activity of pectinmethylesterase, polygalacturonase, cellulase and α- and β-galactosidase was studied. No polygalacturonase and cellulase activity was found. The two galactosidases showed higher activity than pectinmethylesterase (25–290 units/g tissue versus 0.3–0.4 units/g tissue), especially in Cabernet Sauvignon grapes, although in Monastrell grapes α- and β-galactosidase activity was low, which may explain the large amount of galactose in Monastrell grapes cell wall.

Influence of the yeast strain on Monastrell wine colour

Abstract Two commercial yeast strains were assayed during the winemaking process of Monastrell grapes to determine their influence on colour and phenolic composition of the resulting wines during alcoholic fermentation and maturation. The results showed that in 2002, the wines did not present great differences but in 2003 higher colour intensity and phenolic compounds content were detected when one of the commercial strains was used. A discriminant statistical analysis clearly showed that different yeasts led to different wines as regard their chromatic characteristics. Industrial relevance The importance of yeast in winemaking is extensively known since they are responsible for the transformation of sugars into ethanol and for the formation of the most significant aroma compounds in wines. However, they may also participate in wine colour and this role is usually not taken into account in the wine industry. The choice of a yeast strain is an important factor since these microorganisms have the capacity to retain or adsorb phenolic compounds and, on the other hand, yeast may contribute to stabilizing wine colour, as a result of participating in the formation of vitisins during fermentation or liberating mannoproteins that have the capacity to bind to anthocyanins and tannins, protecting them from precipitation. Two commercial yeast strains were assayed during the winemaking process of Monastrell grapes to determine their influence on colour and phenolic composition of the resulting wines during alcoholic fermentation and maturation. The results showed that higher colour intensity and phenolic compounds content were detected when one of the commercial strains was used, both during fermentation and wine aging, and may be used as a tool during winemaking for obtaining stable and highly coloured wines.

Anthocyanin fingerprint of grapes: environmental and genetic variations

AbstractThe anthocyanin content and fingerprint of four different Vitis vinifera L. varieties (Cabernet Sauvignon, Merlot, Syrah and Monastrell), the last grown in two different locations, were studied during three growing seasons to determine how seasonal conditions and location affect the content of berry anthocyanins and their relative percentages. Important differences in the content of anthocyanins were detected among varieties—Monastrell grapes from one of the locations presenting the highest anthocyanin content—when expressed as µg g−1 of skin. However, due to the large berry size of Monastrell grapes, when the results were expressed as mg kg−1 of berry, Cabernet Sauvignon and Syrah grapes presented the highest concentration. Significant differences were found as regards growing season, the concentration of anthocyanins being lowest in 2003, the warmest year. As regards the relative percentage of the different anthocyanins, substantial differences were found between varieties, but again, the results were also influenced by the year under study. When the percentages of anthocyanins were used as variables in a discriminant analysis, a 100% correct classification of the four different varieties was obtained. Moreover, to check the suitability of this tool for classifying varieties, data referring to the anthocyanin percentages of the four varieties grown in very different agroecological conditions and at different ripening stages were tested with the model we have built, 89% of correct classification being achieved. Copyright © 2006 Society of Chemical Industry

A first approach towards the relationship between grape skin cell-wall composition and anthocyanin extractability

The composition of skin cell-walls from four different grape varieties ( Vitis vinifera L., cv. Cabernet Sauvignon, Merlot, Syrah and Monastrell, the later harvested in three different locations) has been studied, trying to correlate those differences found in cell-wall composition among varieties with their degree of ripeness and with the easiness of anthocyanin extractability. The results of an anthocyanin extractability assay showed that the anthocyanins from Monastrell grape skins might be more difficult to extract than those from the other varieties. The study of the cell-wall composition showed some differences in uronic acids, cellulosic glucose, proteins and polyphenol content of cell-walls among varieties, and also differences between the Monastrell grapes cultivated in different locations were detected. Little differences could be found among the different samples regarding the non-cellulosic neutral sugars. In trying to look if differences in the extractability index were related to cell-wall composition and to help to clarify some of the mechanism involved in the anthocyanin extractability, a multiple regression analysis was conducted. The results showed that a model could be built up explaining a high percentage of the variability in the extractability index, using the content of the different components of the skin cell-wall as independent variables. Following this approach, the differences on the easiness of anthocyanin extractability in grape samples could be based in differences in pectin and cellulose content, but also, differences occurring on arabinoxylan, arabinogalactan and xyloglucan could be of importance.

Differences in Anthocyanin Extractability from Grapes to Wines According to Variety

The anthocyanin concentration of <i>Vitis vinifera</i> L. cvs. Cabernet Sauvignon, Merlot, Syrah, and Monastrell grape skins was determined together with anthocyanin extractability at the exact time of harvest (measured by an extractability assay based on the comparison of the anthocyanin concentration of two different solutions obtained after macerating the grapes for four hours at two different pH values). These data were compared with the anthocyanin concentration and chromatic characteristics of the resulting wines. Monastrell grapes from the Jumilla area had the highest anthocyanin concentration (whether expressed as μg/g or mg/kg of berries), but the extractability assay indicated the difficulty of their extraction. The extractability assay for Cabernet Sauvignon, Merlot, and Syrah indicated that their anthocyanins could be extracted easily, which was confirmed by the chromatic analysis of the resulting wines. Cabernet Sauvignon and Syrah wines presented the highest wine color intensity, although their anthocyanin concentration in the grapes was lower than that of Monastrell grapes. Results indicated that the above extractability assay could be useful for predicting some important chromatic wine parameters and for planning the fermentation process according to the characteristics of the grapes at the exact time of harvest and the desired wine.

Effect of moderate irrigation on grape composition during ripening

The effect of moderate irrigation on berry composition during the ripening of Monastrell grapes and the quality of wines produced from these grapes in a very dry area of southeastern Spain have been studied. The results showed that irrigated grapes reached higher weights but this did not impair sugar accumulation. Titratable acidity and pH were only slightly affected by irrigation, titratable acidity was higher in only one year in the most irrigated grapes at the end of ripening, mainly due to a higher malic acid content. Anthocyanin content in must was slightly lower in irrigated grapes. The results of the sensory analysis of the wines showed that wines made from non irrigated grapes usually obtained the highest scores for quality and intensity of color and aroma although differences were small.

Effect of deficit irrigation on anthocyanin content of Monastrell grapes and wines

&lt;p style="text-align: justify;"&gt;The results showed that moderately irrigated vines produced berries with a higher anthocyanin content (expressed as mg/100 berries) than non-irrigated vines. These findings suggest that moderate levels of water doses may actually improve the physiological status of vines grown in very dry areas, resulting in higher yields and higher quality grapes. The higher yields were mainly related to larger berry size which led to a lower anthocyanin content when expressed as mg/kg, due to a dilution effect. This fact is also responsible for the lower anthocyanin content of the wines elaborated with grapes from irrigated vines although irrigation per se did not decrease the concentration of anthocyanins in grapes.&lt;/p&gt;

The maceration process during winemaking extraction of anthocyanins from grape skins into wine

The rate of anthocyanin extraction from skins of Monastrell grapes into wine during the maceration process has been studied by following anthocyanin accumulation in wine and its decrease in crushed skins. The most important changes occurred during the first 7 days of maceration; the following 7 days saw very little variation in the levels of the anthocyanins found in the wine or the crushed skins. The anthocyanin profile of the wines was quite different from that of the grape skins, whereas the crushed grape skins had a profile very similar to the profile of the grape skins at the time of harvest. Any differences in the proportions of the different anthocyanins found in Monastrell grapes and wines cannot therefore be attributed to different rates of extraction for each of the anthocyanins during winemaking. Other explanations, such as degradation or yeast cell wall adsorption, must be sought.

Effect of Organic Farming Practices on the Level of Latent Polyphenol Oxidase in Grapes

: The levels of polyphenol oxidase (PPO) in organic as compared with conventional Monastrell grapes were examined in this study. The enzyme was partially purified using the Triton X-114 method, and in both cases it was obtained in a latent state, being activated by different methods (acid shocking, detergents, and proteases). PPO purified from both organic and conventional Monastrell grapes had the same isoenzymatic form, appearing as the same single band in polyacrylamide gel electrophoresis. However, diphenolase activity of activated PPO in organic grapes was 2 times higher than in conventional grapes, independent of the activation method used. Moreover, the proteolytic activation method, using trypsin, was the most effective for this latent PPO.

Determination of piceid and resveratrol in Spanish wines deriving from Monastrell (Vitis vinifera L.) grape variety.

The presence of stilbenes in wine is becoming an important issue due to their claimed relation to a low incidence in coronary diseases and their increasing implication as cancer chemopreventive and neuroprotective agents. Total resveratrol content, quantified as glucoside and aglycone forms of resveratrol, has been determined in a survey of 45 Monastrell monovarietal Spanish red wine types (around 135 wine samples), belonging to Alicante and Bullas appellations. The average between ratio glucoside/aglycone forms of resveratrol in these wines was considerably high, ranging from 82 to 91% of resveratrol in its glycosidic form. This characteristic was observed in a high percentage of the studied wines, which were made under different winemaking procedures, and from different vintages (1995-2002). In addition, wines made using macerative fermentations with double amount of solid parts ("doble pasta") reached the highest levels of total stilbene content expressed as resveratrol equivalent, i.e., 30 mg/L (average of 18.8 mg/L). It can be concluded that high resveratrol glucoside concentration and low free isomer content can be considered characteristics of the Monastrell variety, as it happens to red wines deriving from other varieties grown at warm climates. This fact, also observed for other French and Portuguese red varieties, might play an important role in food habits involving these types of wines.

Stir bar sorptive extraction applied to volatile constituents evolution during Vitis vinifera ripening.

The stir bar sorptive extraction (SBSE) technique is used to determine volatile constituents in Monastrell grapes. The method proposed involves a maceration step lasting 2 h and a sorption time of 6 h. The coefficients of variation obtained were <4% in the case of the volatile compounds and <2% for the internal standard. The behavior of the volatiles during grape ripening was studied, and 34 compounds were determined, among which geranyl acetone, geranyl butyrate, farnesol, and a bicycloterpene, tentatively identified as 6-methylene[3.1.0]byciclohexane, were recorded for the first time in this variety. The highest terpene and norisoprenoid contents together with the lowest values of C6 compounds were observed during the fifth week of ripening, meaning that this would be the optimal time for harvesting in terms of volatile compounds.

Evolution of chlorpyrifos, fenarimol, metalaxyl, penconazole, and vinclozolin in red wines elaborated by carbonic maceration of Monastrell grapes.

The influence of the different steps involved in the wine-making process on the disappearance of chlorpyrifos, fenarimol, metalaxyl, penconazole, and vinclozolin in red wines elaborated by carbonic maceration of Monastrell grapes was studied. The initial levels of the residues in grapes ranged from 0.28 mg/kg (penconazole) to 1 mg/kg (chlorpyrifos). Ten days after the beginning of maceration, the compound that had decreased least was chlorpyrifos (83% of initial value remaining), whereas metalaxyl, the least persistent of the residues, had decreased to 49% of its initial value. In the free-run juice, on the other hand, the highest percentage remaining corresponded to metalaxyl (10%) and the lowest to chlorpyrifos (0. 1%). After pressing, the percentages of initial values eliminated in pomace varied from 82.7% for chlorpyrifos to 17.7% for metalaxyl, whereas in the press juice the opposite was the case (37% metalaxyl and 2% chlorpyrifos remaining). In finished wine, there were residues of all the pesticides, with the exception of chlorpyrifos, metalaxyl (21%) being the most persistent. The percentages eliminated in the lees varied from 1.5 to 2.5% of the initial value.

Multivariate classification of wines from seven clones of Monastrell grapes

Multivariate classification of wines from seven clones of Monastrell grapes

Multivariate classification of wines from seven clones of Monastrell grapes

The enological characteristics of different clones of Monastrell grapes have been studied. The wines obtained from different clones were subjected to chemical analyses, including the determination of organic acids, colour characteristics and mineral elements. Significant differences were found among clones. To check if these analytical parameters could correctly classify the wine samples, multivariate statistical analysis was done. Cluster and principal component analysis classified correctly samples belonging to the same clone. © 2000 Society of Chemical Industry

Effect of diverse enzyme preparations on the extraction and evolution of phenolic compounds in red wines

In this report, the effect of diverse enzyme preparations normally used in the elaboration of red wines, on certain colouring indices has been studied: the colouring intensity, tone, anthocyanins, index of total polyphenols, index of Folin-Cicalteu and anthocyanin broken up into monomers, red polymers and brown polymers. Wines elaborated with the Monastrell grape variety have been used and the evolution of these compounds during the vinification and the conservation process in bottles has been followed. It has been proved that all the enzyme preparations increase the extraction of polyphenols and the quality of colour obtained and the changes of these parameters in the conservation process, is the same in the control wine as in the treated wines.