Oxidation of white wines implies modification of their organoleptic characteristics and in most c... more Oxidation of white wines implies modification of their organoleptic characteristics and in most cases degradation of their overall quality. The development of oxidative browning is associated with polyphenol oxidation, and it can be accelerated by the presence of metal ions such as Fe 2+ while it may be delayed by the addition of antioxidants, such as selenium (Se) and SO2. The aim of this study was to study the browning capacity of Assyrtiko white wines after Se addition at two temperatures (35 and 50°C) employing the accelerated browning test. For this purpose, two concentrations of Se were added at the wine, either alone or with the simultaneous presence of Fe 2+ , and the absorbance at 420 nm was monitored for twelve days. It was also of interest to evaluate the changes of other analytical parameters which are implicated in wine oxidation such as: SO2 content (free and total). Browning was approached from a kinetic point of view and the study was focused on the implication of oxidants and antioxidants on browning rate. The results showed that the addition of Se protected wine color and preserved total SO2 at 35°C while at 50°C these effects were not any longer observed. GSH content of the samples containing Se after 12 days of accelerated ageing was similar with that of the control.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Two wild-type Saccharomyces cerevisiae yeast strains (Sa and Sb) were tested for white wine produ... more Two wild-type Saccharomyces cerevisiae yeast strains (Sa and Sb) were tested for white wine production using Assyrtiko grape of Santorini. A third commercial Saccharomyces strain was also studied for comparison reasons. Two concentrations of yeast extract and diammonium phosphate (DAP) were added to the must (150 and 250 mg/L) in order to evaluate the effect of nitrogen content on the final wine quality. Analytical methods (HPLC, GC-MS) and sensory analysis were employed to assess the quality of the wines. Fermentation kinetics were monitored throughout the experiment. By the second day of fermentation, all strains showed an approximate consumption of 70% of amino acids. Differences among strains were observed regarding inorganic nitrogen requirements. Sb strain resulted in higher concentrations of higher alcohols (1.9-fold) and ketones (5.6-fold) and lower concentrations of esters (1.2-fold) compared to the control, while Sa strain resulted in higher content of fatty acids (2.1-fol...
Poster presentado en el 10th International Symposium of Enology (OENO 2015), celebrado en Burdeos... more Poster presentado en el 10th International Symposium of Enology (OENO 2015), celebrado en Burdeos del 19 de junio al 1 de julio de 2015.
'Xinomavro' (the second planted red Greek variety behind 'Agiorgitiko') generally produces wines ... more 'Xinomavro' (the second planted red Greek variety behind 'Agiorgitiko') generally produces wines that are light in colour but with increased astringency, possibly related to grape flavonoid amount and composition; although irrigation is accepted as an effective means to enhance grape phenolic maturity, its role has not yet been sufficiently studied in the case of Xinomavro. This study aimed to determine the effect of post-veraison irrigation on berry anthocyanin and proanthocyanidin amount and composition, of field-grown Xinomavro vines (Vitis vinifera L.), under the typical summer conditions of Northern Greece. In a 10-year-old Xinomavro vineyard, two post-veraison watering regimes were applied-irrigation starting 20 days after veraison (mid-ripening irrigation, MRI) and irrigation starting immediately after veraison was completed (after veraison irrigation, AVI)-alongside non irrigated vines (NI), and vines irrigated continuously from berry set through harvest (continuous irrigation, CI). Proanthocyanidin composition was determined in both skins and seeds by employing phloroglucinolysis followed by HPLC-UV and MS detection (high-performance liquid chromatographic with tandem mass spectrometric and ultraviolet absorbance detection), and the anthocyanin profile was identified only in the skin extracts by HPLC-UV (high-performance liquid chromatographic with ultraviolet absorbance detection). Post-veraison irrigation increased yield parameters and reduced anthocyanin levels and the proportion of their stable forms (acylated vs. non-acylated, tri-oxygenated and methoxylated on the Bring vs. di-oxygenated and hydroxylated), compared to NI vines; however, these effects were more pronounced in the case of early post-veraison irrigation (AVI) than late-season irrigation (MRI). Irrigation also increased the mean Degree of Polymerization (mDP) and prodelphinidin percentage of skin tannins and decreased mDP of seed tannins. In the light of the necessity to control the accelerated ripening under the increasingly hotter and drier climatic conditions, late irrigation (MRI) might provide a solution to avoid excessive sugar levels and allow a slightly higher yield without significant reductions in berry phenolic content. The results suggest that the optimisation of the timing of irrigation could provide an effective adaptation strategy to climate change in Mediterranean viticultural areas.
Fourier transform infrared spectroscopy (FT-IR) has gained popularity in the wine sector due to i... more Fourier transform infrared spectroscopy (FT-IR) has gained popularity in the wine sector due to its simplicity and ability to provide a wine’s fingerprint. For this reason, it is often used for authentication and traceability purposes with more than satisfactory results. In this review, an outline of the reasons why authenticity and traceability are important to the wine sector is given, along with a brief overview of the analytical methods used for their attainment; statistical issues and compounds, on which authentication usually is based, are discussed. Moreover, insight on the mode of action of FT-IR is given, along with successful examples from its use in different areas of interest for classification. Finally, prospects and challenges for suggested future research are given. For more accurate and effective analyses, the construction of a large database consisting of wines from different regions, varieties and winemaking protocols is suggested.
Aim: The aim of this project was to identify the characteristic flavor and off-flavor compounds t... more Aim: The aim of this project was to identify the characteristic flavor and off-flavor compounds that could be used as potential oxidation markers to establish the quality of the stored wines and to predict the wines’ shelf life employing a mathematical model.Materials and methods: Six mono-varietal Greek white wines (produced by three varieties) were bottled using two types of corks having different oxygen permeability properties. Volatile compounds, resistance to oxidative degradation and total and free-sulfur dioxide content were recorded in all samples. Results were processed using the root cause analysis versus packaging and storage conditions. Additionally, a predictive model has been constructed to estimate the shelf life of the bottled wine.Results: Physicochemical analysis indicated the absence of significant oxidative degradations during the first 7 months. Furthermore, 12-month stored samples showed a significant alteration in their flavor profile. Based on the concentrati...
The aim of this work was to examine the possible use of High Hydrostatic Pressure (HHP) as an alt... more The aim of this work was to examine the possible use of High Hydrostatic Pressure (HHP) as an alternative method for wine preservation, which could also lead to the production of wines with reduced amounts of SO2. For this purpose, red wine samples containing 0 ppm, 30 ppm, 60 ppm and 100 ppm of sulphur dioxide (SO2) were subjected to pressure of 350 MPa for 10 min at 8 ∘C. A second set of samples containing only SO2 was used as control. Colour parameters, acetic acid, total anthocyanin and phenolic contents and antioxidant activity were determined over a period of twelve months. During the first four months, most of the differences observed regarding the chemical composition of the pressurized and unpressurized wines were not statistically significant. However, after the period of six months, the pressurized samples in general were characterized by higher average values % yellow colour and acetic acid and lower of % red colour, total anthocyanin and phenolic content compared to the...
Journal of Chemical Technology & Biotechnology, 2017
This article has been accepted for publication and undergone full peer review but has not been th... more This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as
Current Research in Nutrition and Food Science Journal, 2016
A Raman spectroscopic method and the conventional distillation method for the determination of al... more A Raman spectroscopic method and the conventional distillation method for the determination of alcohol content % (v/v) in Greek spirit Tsipouro used. A univariate calibration model was constructed employing the band area at 880 cm-1 of standard ethanol solutions. The concentrations of 46 samples were then measured using the calibration model and the results were compared with those obtained using the conventional analysis employing a distillation step. Alcohol content in Greek spirit Tsipouro measured with the conventional method ranged from 35.1 to 71.2 % (v/v). The determination coefficient (R2) value was 0.9997 while the corresponding values of the relative errors ranged between – 13.1 -1.0 %. According to the proposed method the alcohol concentration in Greek spirit Tsipouro ranged from 27.7 to 68.2 % (v/v). The proposed method is simple, rapid, economical and does not require any sample pre-treatment steps. It could be a starting point for the design of more specific models acc...
Oak wood has commonly been used in wine aging but recently other wood types such as Acacia and Ch... more Oak wood has commonly been used in wine aging but recently other wood types such as Acacia and Chestnut, have attracted the interest of the researchers due to their possible positive contribution to wine quality. However, only the use of oak and chestnut woods is approved by the International Enological Codex of the International Organisation of Vine and Wine. In this study Fourier Transform (FT)-mid-infrared spectroscopy combined with Discriminant Analysis was used to differentiate wines aged in barrels made from French oak, American oak, Acacia and Chestnut and in tanks with oak chips, over a period of 12 months. Two red (Mandilaria, Kotsifali) and two white (Vilana, Dafni) native Greek grape varieties where used to produce four wines. The Fourier Transform Infrared (FT-IR) spectra of the samples were recorded on a Zinc Selenide (ZnSe) window after incubation at 40°C for 30 min. A complete differentiation of the samples according to both the type of wood used and the contact time was achieved based on their FT-IR spectra.
Wine quality is a complex attribute, thus single berry parameters are not adequate to define grap... more Wine quality is a complex attribute, thus single berry parameters are not adequate to define grape suitability for the production of specific wines. Fuzzy logic systems are particularly suited for aggregating multiple data to feed multi-variables decision support systems. The aim of the present study was the development of a simple in use and reliable tool based on fuzzy logic multi criteria decision making to objectively classify wine quality based on selected grape attributes. For this purpose, representative berry samples were harvested and vinified for two consecutive years from thirteen commercial vineyards in Nemea, Greece planted with Vitis vinifera cv. Agiorgitiko. Total soluble solids, pH, berry volume, botrytis infection, grape seed colorization, anthocyanin extractability, optical density (OD 520) and skin phenolics (Dpell) were measured at harvest and were used in the tool as inputs. Moreover, the produced wines were sensory evaluated by an experienced and trained panel. The ranking of the vineyards, according to the tasting panel, was compared to the ranking made by the tool and the results showed high general agreement between them suggesting that the latter was able to model expert knowledge successfully. According to the results, the fuzzy logic multi criteria decision making tool could allow the incorporation of grape quality parameters at harvest into a single index providing grape growers and wine producers with a valuable tool for classifying wine quality.
The effect of oxidation on the organoleptic properties of white wines mostly involves increased b... more The effect of oxidation on the organoleptic properties of white wines mostly involves increased browning color, loss of the fruity aromas, and appearance of unpleasant odors. Browning, however, is known to be related with polyphenol oxidation and therefore it may be delayed by the presence of antioxidants such as selenium (Se) and SO2. On the other hand, the presence of oxidants such as metal ions and H2O2 can accelerate browning and oxidation phenomena. The browning capacity, the phenolic composition (both total and individual contents of flavanols and hydroxycinnamic acids), the antioxidant activity, and the SO2 content of Assyrtiko white wines were studied after the addition of Fe2+ and H2O2 and Se at two temperatures, employing an accelerated test. Browning was approached from a kinetic point of view, and the study was focused on the implication of oxidants and antioxidants on browning rate, paying particular attention to the content of major redox-active polyphenols, including ...
Background Soil properties, climatic conditions and cultivation techniques constitute significant... more Background Soil properties, climatic conditions and cultivation techniques constitute significant variables, which affect the quality of the final product. In particular, soil data (soil texture, soil electrical conductivity etc.) and weather data (average temperature, humidity etc.) affect both crop quality data (sugar content, anthocyanins content, phenolic compounds concentrations etc.) and crop quantity data (crop yield, berry weight and size etc.). The aim of this study was to investigate the variations of the microclimatic areas that exist within the same vineyard and their effect on the qualitative and quantitative characteristics of the berry skins and seeds of the grapes. These microclimatic areas could be identified and classified as those which could produce grapes for PDO wines and those which could be used for the production of other types of wines.
Oxidation of white wines implies modification of their organoleptic characteristics and in most c... more Oxidation of white wines implies modification of their organoleptic characteristics and in most cases degradation of their overall quality. The development of oxidative browning is associated with polyphenol oxidation, and it can be accelerated by the presence of metal ions such as Fe 2+ while it may be delayed by the addition of antioxidants, such as selenium (Se) and SO2. The aim of this study was to study the browning capacity of Assyrtiko white wines after Se addition at two temperatures (35 and 50°C) employing the accelerated browning test. For this purpose, two concentrations of Se were added at the wine, either alone or with the simultaneous presence of Fe 2+ , and the absorbance at 420 nm was monitored for twelve days. It was also of interest to evaluate the changes of other analytical parameters which are implicated in wine oxidation such as: SO2 content (free and total). Browning was approached from a kinetic point of view and the study was focused on the implication of oxidants and antioxidants on browning rate. The results showed that the addition of Se protected wine color and preserved total SO2 at 35°C while at 50°C these effects were not any longer observed. GSH content of the samples containing Se after 12 days of accelerated ageing was similar with that of the control.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Two wild-type Saccharomyces cerevisiae yeast strains (Sa and Sb) were tested for white wine produ... more Two wild-type Saccharomyces cerevisiae yeast strains (Sa and Sb) were tested for white wine production using Assyrtiko grape of Santorini. A third commercial Saccharomyces strain was also studied for comparison reasons. Two concentrations of yeast extract and diammonium phosphate (DAP) were added to the must (150 and 250 mg/L) in order to evaluate the effect of nitrogen content on the final wine quality. Analytical methods (HPLC, GC-MS) and sensory analysis were employed to assess the quality of the wines. Fermentation kinetics were monitored throughout the experiment. By the second day of fermentation, all strains showed an approximate consumption of 70% of amino acids. Differences among strains were observed regarding inorganic nitrogen requirements. Sb strain resulted in higher concentrations of higher alcohols (1.9-fold) and ketones (5.6-fold) and lower concentrations of esters (1.2-fold) compared to the control, while Sa strain resulted in higher content of fatty acids (2.1-fol...
Poster presentado en el 10th International Symposium of Enology (OENO 2015), celebrado en Burdeos... more Poster presentado en el 10th International Symposium of Enology (OENO 2015), celebrado en Burdeos del 19 de junio al 1 de julio de 2015.
'Xinomavro' (the second planted red Greek variety behind 'Agiorgitiko') generally produces wines ... more 'Xinomavro' (the second planted red Greek variety behind 'Agiorgitiko') generally produces wines that are light in colour but with increased astringency, possibly related to grape flavonoid amount and composition; although irrigation is accepted as an effective means to enhance grape phenolic maturity, its role has not yet been sufficiently studied in the case of Xinomavro. This study aimed to determine the effect of post-veraison irrigation on berry anthocyanin and proanthocyanidin amount and composition, of field-grown Xinomavro vines (Vitis vinifera L.), under the typical summer conditions of Northern Greece. In a 10-year-old Xinomavro vineyard, two post-veraison watering regimes were applied-irrigation starting 20 days after veraison (mid-ripening irrigation, MRI) and irrigation starting immediately after veraison was completed (after veraison irrigation, AVI)-alongside non irrigated vines (NI), and vines irrigated continuously from berry set through harvest (continuous irrigation, CI). Proanthocyanidin composition was determined in both skins and seeds by employing phloroglucinolysis followed by HPLC-UV and MS detection (high-performance liquid chromatographic with tandem mass spectrometric and ultraviolet absorbance detection), and the anthocyanin profile was identified only in the skin extracts by HPLC-UV (high-performance liquid chromatographic with ultraviolet absorbance detection). Post-veraison irrigation increased yield parameters and reduced anthocyanin levels and the proportion of their stable forms (acylated vs. non-acylated, tri-oxygenated and methoxylated on the Bring vs. di-oxygenated and hydroxylated), compared to NI vines; however, these effects were more pronounced in the case of early post-veraison irrigation (AVI) than late-season irrigation (MRI). Irrigation also increased the mean Degree of Polymerization (mDP) and prodelphinidin percentage of skin tannins and decreased mDP of seed tannins. In the light of the necessity to control the accelerated ripening under the increasingly hotter and drier climatic conditions, late irrigation (MRI) might provide a solution to avoid excessive sugar levels and allow a slightly higher yield without significant reductions in berry phenolic content. The results suggest that the optimisation of the timing of irrigation could provide an effective adaptation strategy to climate change in Mediterranean viticultural areas.
Fourier transform infrared spectroscopy (FT-IR) has gained popularity in the wine sector due to i... more Fourier transform infrared spectroscopy (FT-IR) has gained popularity in the wine sector due to its simplicity and ability to provide a wine’s fingerprint. For this reason, it is often used for authentication and traceability purposes with more than satisfactory results. In this review, an outline of the reasons why authenticity and traceability are important to the wine sector is given, along with a brief overview of the analytical methods used for their attainment; statistical issues and compounds, on which authentication usually is based, are discussed. Moreover, insight on the mode of action of FT-IR is given, along with successful examples from its use in different areas of interest for classification. Finally, prospects and challenges for suggested future research are given. For more accurate and effective analyses, the construction of a large database consisting of wines from different regions, varieties and winemaking protocols is suggested.
Aim: The aim of this project was to identify the characteristic flavor and off-flavor compounds t... more Aim: The aim of this project was to identify the characteristic flavor and off-flavor compounds that could be used as potential oxidation markers to establish the quality of the stored wines and to predict the wines’ shelf life employing a mathematical model.Materials and methods: Six mono-varietal Greek white wines (produced by three varieties) were bottled using two types of corks having different oxygen permeability properties. Volatile compounds, resistance to oxidative degradation and total and free-sulfur dioxide content were recorded in all samples. Results were processed using the root cause analysis versus packaging and storage conditions. Additionally, a predictive model has been constructed to estimate the shelf life of the bottled wine.Results: Physicochemical analysis indicated the absence of significant oxidative degradations during the first 7 months. Furthermore, 12-month stored samples showed a significant alteration in their flavor profile. Based on the concentrati...
The aim of this work was to examine the possible use of High Hydrostatic Pressure (HHP) as an alt... more The aim of this work was to examine the possible use of High Hydrostatic Pressure (HHP) as an alternative method for wine preservation, which could also lead to the production of wines with reduced amounts of SO2. For this purpose, red wine samples containing 0 ppm, 30 ppm, 60 ppm and 100 ppm of sulphur dioxide (SO2) were subjected to pressure of 350 MPa for 10 min at 8 ∘C. A second set of samples containing only SO2 was used as control. Colour parameters, acetic acid, total anthocyanin and phenolic contents and antioxidant activity were determined over a period of twelve months. During the first four months, most of the differences observed regarding the chemical composition of the pressurized and unpressurized wines were not statistically significant. However, after the period of six months, the pressurized samples in general were characterized by higher average values % yellow colour and acetic acid and lower of % red colour, total anthocyanin and phenolic content compared to the...
Journal of Chemical Technology & Biotechnology, 2017
This article has been accepted for publication and undergone full peer review but has not been th... more This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as
Current Research in Nutrition and Food Science Journal, 2016
A Raman spectroscopic method and the conventional distillation method for the determination of al... more A Raman spectroscopic method and the conventional distillation method for the determination of alcohol content % (v/v) in Greek spirit Tsipouro used. A univariate calibration model was constructed employing the band area at 880 cm-1 of standard ethanol solutions. The concentrations of 46 samples were then measured using the calibration model and the results were compared with those obtained using the conventional analysis employing a distillation step. Alcohol content in Greek spirit Tsipouro measured with the conventional method ranged from 35.1 to 71.2 % (v/v). The determination coefficient (R2) value was 0.9997 while the corresponding values of the relative errors ranged between – 13.1 -1.0 %. According to the proposed method the alcohol concentration in Greek spirit Tsipouro ranged from 27.7 to 68.2 % (v/v). The proposed method is simple, rapid, economical and does not require any sample pre-treatment steps. It could be a starting point for the design of more specific models acc...
Oak wood has commonly been used in wine aging but recently other wood types such as Acacia and Ch... more Oak wood has commonly been used in wine aging but recently other wood types such as Acacia and Chestnut, have attracted the interest of the researchers due to their possible positive contribution to wine quality. However, only the use of oak and chestnut woods is approved by the International Enological Codex of the International Organisation of Vine and Wine. In this study Fourier Transform (FT)-mid-infrared spectroscopy combined with Discriminant Analysis was used to differentiate wines aged in barrels made from French oak, American oak, Acacia and Chestnut and in tanks with oak chips, over a period of 12 months. Two red (Mandilaria, Kotsifali) and two white (Vilana, Dafni) native Greek grape varieties where used to produce four wines. The Fourier Transform Infrared (FT-IR) spectra of the samples were recorded on a Zinc Selenide (ZnSe) window after incubation at 40°C for 30 min. A complete differentiation of the samples according to both the type of wood used and the contact time was achieved based on their FT-IR spectra.
Wine quality is a complex attribute, thus single berry parameters are not adequate to define grap... more Wine quality is a complex attribute, thus single berry parameters are not adequate to define grape suitability for the production of specific wines. Fuzzy logic systems are particularly suited for aggregating multiple data to feed multi-variables decision support systems. The aim of the present study was the development of a simple in use and reliable tool based on fuzzy logic multi criteria decision making to objectively classify wine quality based on selected grape attributes. For this purpose, representative berry samples were harvested and vinified for two consecutive years from thirteen commercial vineyards in Nemea, Greece planted with Vitis vinifera cv. Agiorgitiko. Total soluble solids, pH, berry volume, botrytis infection, grape seed colorization, anthocyanin extractability, optical density (OD 520) and skin phenolics (Dpell) were measured at harvest and were used in the tool as inputs. Moreover, the produced wines were sensory evaluated by an experienced and trained panel. The ranking of the vineyards, according to the tasting panel, was compared to the ranking made by the tool and the results showed high general agreement between them suggesting that the latter was able to model expert knowledge successfully. According to the results, the fuzzy logic multi criteria decision making tool could allow the incorporation of grape quality parameters at harvest into a single index providing grape growers and wine producers with a valuable tool for classifying wine quality.
The effect of oxidation on the organoleptic properties of white wines mostly involves increased b... more The effect of oxidation on the organoleptic properties of white wines mostly involves increased browning color, loss of the fruity aromas, and appearance of unpleasant odors. Browning, however, is known to be related with polyphenol oxidation and therefore it may be delayed by the presence of antioxidants such as selenium (Se) and SO2. On the other hand, the presence of oxidants such as metal ions and H2O2 can accelerate browning and oxidation phenomena. The browning capacity, the phenolic composition (both total and individual contents of flavanols and hydroxycinnamic acids), the antioxidant activity, and the SO2 content of Assyrtiko white wines were studied after the addition of Fe2+ and H2O2 and Se at two temperatures, employing an accelerated test. Browning was approached from a kinetic point of view, and the study was focused on the implication of oxidants and antioxidants on browning rate, paying particular attention to the content of major redox-active polyphenols, including ...
Background Soil properties, climatic conditions and cultivation techniques constitute significant... more Background Soil properties, climatic conditions and cultivation techniques constitute significant variables, which affect the quality of the final product. In particular, soil data (soil texture, soil electrical conductivity etc.) and weather data (average temperature, humidity etc.) affect both crop quality data (sugar content, anthocyanins content, phenolic compounds concentrations etc.) and crop quantity data (crop yield, berry weight and size etc.). The aim of this study was to investigate the variations of the microclimatic areas that exist within the same vineyard and their effect on the qualitative and quantitative characteristics of the berry skins and seeds of the grapes. These microclimatic areas could be identified and classified as those which could produce grapes for PDO wines and those which could be used for the production of other types of wines.
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