Sandra Cortés - Academia.edu (original) (raw)

Papers by Sandra Cortés

Research paper thumbnail of Differentiation of Spanish Alcoholic Drinks, Orujo , Obtained from Red and White Grape Pomace Distillation: Volatile Composition

International Journal of Food Properties, 2011

A total of 61 samples of Galician (NW Spain) Orujo spirits, 28 from white grape pomace and 33 fro... more A total of 61 samples of Galician (NW Spain) Orujo spirits, 28 from white grape pomace and 33 from red grape pomace, were analyzed by gas Chronoatography with flameionization detector (GC-FID) in order to determine which volatile compounds show significant differences (p ≤ 0.05). Orujo spirits obtained from white grape residues showed a higher concentration of methanol, hexanols, hexenols, ethyl lactate, benzaldehyde, 2-butanol, and rate 1-propanol/2-methyl-1-propanol, which indicated a high trend to the degradation by anaerobic microorganisms during the storage and alcoholic fermentation of the raw material. However, in the spirits from red grape, the concentration of ethyl esters was higher as was the concentration of the compounds that are derived from the activity of aerobic bacteria or oxygen contact with the fermented grape pomace, especially acetaldehyde and ethyl acetate.

Research paper thumbnail of Effect of the Glass Shape on Flavor Perception of "Toasted Wine" from Ribeiro (NW Spain)

Journal of Sensory Studies, 2008

The objective of this study was to determine the effect of geometries of nine glass types on the ... more The objective of this study was to determine the effect of geometries of nine glass types on the sensory perception of sweet "toasted wine" from the Appellation of Origin Ribeiro wine. Nine wine tasters conducted the sensory evaluation. The subjects compared six Ribeiro wines with nine different glasses. Visual, nose and taste expression of wines were rated repeatedly before and after drinking in each type of glass. Harmony and functionality were rated as well.

Research paper thumbnail of Use of a PGU1 recombinant Saccharomyces cerevisiae strain in oenological fermentations

Journal of Applied Microbiology, 2000

Aim: The aim of this work was the construction of an oenological Saccharomyces cerevisiae strain ... more Aim: The aim of this work was the construction of an oenological Saccharomyces cerevisiae strain able to overexpress the PGU1 gene in order to be used in trial fermentations. Methods and Results: The recombinant strain is able to secrete an active endopolygalacturonase into the medium leaving its fermentation ability essentially unchanged. Wines obtained with the recombinant strain and the untransformed counterpart did not differ in their physicochemical parameters or major sensory characteristics. The time needed for wine ®ltration was dramatically reduced in wines elaborated with the PGU1 recombinant strain, and was comparable to the ®ltration time shown by wines elaborated from must supplemented with fungal pectolytic enzymes. Conclusions: The oenological strain constructed in this work secretes an endopolygalacturonase into the wine in an ef®cient manner, resulting in an improvement in wine ®ltration but preserving wine typicality and keeping the methanol levels unchanged. Signi®cance and Impact of the Study: The PGU1 recombinant strains could be used in oenological fermentations as an alternative to commercial pectolytic enzymes of fungal origin.

Research paper thumbnail of Extraction of Phenolic Acids by Alkaline Hydrolysis from the Solid Residue Obtained after Prehydrolysis of Trimming Vine Shoots

Journal of Agricultural and Food Chemistry, 2010

Contents of hydroxycinnamic and hydroxybenzoic acids were determined in trimming vine shoots afte... more Contents of hydroxycinnamic and hydroxybenzoic acids were determined in trimming vine shoots after sequential treatments of prehydrolysis and alkaline hydrolysis. These treatments allow the complete use of the main fractions involved: cellulose, hemicelluloses and lignin. The alkaline hydrolysis was studied using a factorial design where reaction time (in the range 30-120 min), temperature (50-130 degrees C), and NaOH concentration (4-12 wt % of solution) were the independent variables. The interrelationship between dependent and operational variables was well fitted (R(2) > 0.90) to models including linear, interaction and quadratic terms. Ferulic acid was the most abundant hydroxycinnamate with concentrations ranging from 25.7 to 141.0 mg/L followed by p-coumaric acid (15.5-31.5 mg/L). Gallic acid was the hydroxybenzoic acid released in higher concentration (in the range 2.5-164.6 mg/L). Because of their properties and low toxicity, these compounds are widely used in the food, pharmaceutical and cosmetic industries. Additionally, ferulic acid is used as feedstock for the biotechnological production of flavorings and aroma compounds, including vanillin and vinylguaiacol, or as a constituent in the preparation of foods and skin protection agents, or as a cross-linking agent for the elaboration of food gels. Consequently, ferulic acid solutions can be obtained from renewable plant cell wall materials as a prospective pathway.

Research paper thumbnail of Development of Cost-Effective Media to Increase the Economic Potential for Larger-Scale Bioproduction of Natural Food Additives by Lactobacillus rhamnosus, Debaryomyces hansenii, and Aspergillus niger

Journal of Agricultural and Food Chemistry, 2009

Yeast extract (YE) is the most common nitrogen source in a variety of bioprocesses in spite of th... more Yeast extract (YE) is the most common nitrogen source in a variety of bioprocesses in spite of the high cost. Therefore, the use of YE in culture media is one of the major technical hurdles to be overcome for the development of low-cost fermentation routes, making the search for alternative-cheaper nitrogen sources particularly desired. The aim of the current study is to develop cost-effective media based on corn steep liquor (CSL) and locally available vinasses in order to increase the economic potential for larger-scale bioproduction. Three microorganisms were evaluated: Lactobacillus rhamnosus , Debaryomyces hansenii , and Aspergillus niger . The amino acid profile and protein concentration was relevant for the xylitol and citric acid production by D. hansenii and A. niger , respectively. Metals also played an important role for citric acid production, meanwhile, D. hansenii showed a strong dependence with the initial amount of Mg(2+). Under the best conditions, 28.8 g lactic acid/L (Q(LA) = 0.800 g/L.h, Y(LA/S) = 0.95 g/g), 35.3 g xylitol/L (Q(xylitol) = 0.380 g/L.h, Y(xylitol/S) = 0.69 g/g), and 13.9 g citric acid/L (Q(CA) = 0.146 g/L.h, Y(CA/S) = 0.63 g/g) were obtained. The economic efficiency (E(p/euro)) parameter identify vinasses as a lower cost and more effective nutrient source in comparison to CSL.

Research paper thumbnail of Aromatic Compounds in Wines Produced During Fermentation: Effect of Three Red Cultivars

International Journal of Food Properties, 2007

... Mar Vilanova a * , Sandra Cortés b , José Luis Santiago a , Carmen Martínez a & Esperanza... more ... Mar Vilanova a * , Sandra Cortés b , José Luis Santiago a , Carmen Martínez a & Esperanza Fernández c pages 867-875. ... SAS. 2000. “The SAS System”. In SAS Online Doc. HTML, version 8 , Cary, NC: SAS Institute. View all references]. RESULTS AND DISCUSSION. ...

Research paper thumbnail of Contribution of some grape-derived aromatic compounds to the primary aroma in red wines from cv. Caiño Tinto, cv. Caiño Bravo and cv. Caiño Longo grapes

The Journal of Agricultural Science, 2008

Research paper thumbnail of Differentiation of Spanish Alcoholic Drinks, Orujo , Obtained from Red and White Grape Pomace Distillation: Volatile Composition

International Journal of Food Properties, 2011

A total of 61 samples of Galician (NW Spain) Orujo spirits, 28 from white grape pomace and 33 fro... more A total of 61 samples of Galician (NW Spain) Orujo spirits, 28 from white grape pomace and 33 from red grape pomace, were analyzed by gas Chronoatography with flameionization detector (GC-FID) in order to determine which volatile compounds show significant differences (p ≤ 0.05). Orujo spirits obtained from white grape residues showed a higher concentration of methanol, hexanols, hexenols, ethyl lactate, benzaldehyde, 2-butanol, and rate 1-propanol/2-methyl-1-propanol, which indicated a high trend to the degradation by anaerobic microorganisms during the storage and alcoholic fermentation of the raw material. However, in the spirits from red grape, the concentration of ethyl esters was higher as was the concentration of the compounds that are derived from the activity of aerobic bacteria or oxygen contact with the fermented grape pomace, especially acetaldehyde and ethyl acetate.

Research paper thumbnail of Effect of the Glass Shape on Flavor Perception of "Toasted Wine" from Ribeiro (NW Spain)

Journal of Sensory Studies, 2008

The objective of this study was to determine the effect of geometries of nine glass types on the ... more The objective of this study was to determine the effect of geometries of nine glass types on the sensory perception of sweet "toasted wine" from the Appellation of Origin Ribeiro wine. Nine wine tasters conducted the sensory evaluation. The subjects compared six Ribeiro wines with nine different glasses. Visual, nose and taste expression of wines were rated repeatedly before and after drinking in each type of glass. Harmony and functionality were rated as well.

Research paper thumbnail of Use of a PGU1 recombinant Saccharomyces cerevisiae strain in oenological fermentations

Journal of Applied Microbiology, 2000

Aim: The aim of this work was the construction of an oenological Saccharomyces cerevisiae strain ... more Aim: The aim of this work was the construction of an oenological Saccharomyces cerevisiae strain able to overexpress the PGU1 gene in order to be used in trial fermentations. Methods and Results: The recombinant strain is able to secrete an active endopolygalacturonase into the medium leaving its fermentation ability essentially unchanged. Wines obtained with the recombinant strain and the untransformed counterpart did not differ in their physicochemical parameters or major sensory characteristics. The time needed for wine ®ltration was dramatically reduced in wines elaborated with the PGU1 recombinant strain, and was comparable to the ®ltration time shown by wines elaborated from must supplemented with fungal pectolytic enzymes. Conclusions: The oenological strain constructed in this work secretes an endopolygalacturonase into the wine in an ef®cient manner, resulting in an improvement in wine ®ltration but preserving wine typicality and keeping the methanol levels unchanged. Signi®cance and Impact of the Study: The PGU1 recombinant strains could be used in oenological fermentations as an alternative to commercial pectolytic enzymes of fungal origin.

Research paper thumbnail of Extraction of Phenolic Acids by Alkaline Hydrolysis from the Solid Residue Obtained after Prehydrolysis of Trimming Vine Shoots

Journal of Agricultural and Food Chemistry, 2010

Contents of hydroxycinnamic and hydroxybenzoic acids were determined in trimming vine shoots afte... more Contents of hydroxycinnamic and hydroxybenzoic acids were determined in trimming vine shoots after sequential treatments of prehydrolysis and alkaline hydrolysis. These treatments allow the complete use of the main fractions involved: cellulose, hemicelluloses and lignin. The alkaline hydrolysis was studied using a factorial design where reaction time (in the range 30-120 min), temperature (50-130 degrees C), and NaOH concentration (4-12 wt % of solution) were the independent variables. The interrelationship between dependent and operational variables was well fitted (R(2) > 0.90) to models including linear, interaction and quadratic terms. Ferulic acid was the most abundant hydroxycinnamate with concentrations ranging from 25.7 to 141.0 mg/L followed by p-coumaric acid (15.5-31.5 mg/L). Gallic acid was the hydroxybenzoic acid released in higher concentration (in the range 2.5-164.6 mg/L). Because of their properties and low toxicity, these compounds are widely used in the food, pharmaceutical and cosmetic industries. Additionally, ferulic acid is used as feedstock for the biotechnological production of flavorings and aroma compounds, including vanillin and vinylguaiacol, or as a constituent in the preparation of foods and skin protection agents, or as a cross-linking agent for the elaboration of food gels. Consequently, ferulic acid solutions can be obtained from renewable plant cell wall materials as a prospective pathway.

Research paper thumbnail of Development of Cost-Effective Media to Increase the Economic Potential for Larger-Scale Bioproduction of Natural Food Additives by Lactobacillus rhamnosus, Debaryomyces hansenii, and Aspergillus niger

Journal of Agricultural and Food Chemistry, 2009

Yeast extract (YE) is the most common nitrogen source in a variety of bioprocesses in spite of th... more Yeast extract (YE) is the most common nitrogen source in a variety of bioprocesses in spite of the high cost. Therefore, the use of YE in culture media is one of the major technical hurdles to be overcome for the development of low-cost fermentation routes, making the search for alternative-cheaper nitrogen sources particularly desired. The aim of the current study is to develop cost-effective media based on corn steep liquor (CSL) and locally available vinasses in order to increase the economic potential for larger-scale bioproduction. Three microorganisms were evaluated: Lactobacillus rhamnosus , Debaryomyces hansenii , and Aspergillus niger . The amino acid profile and protein concentration was relevant for the xylitol and citric acid production by D. hansenii and A. niger , respectively. Metals also played an important role for citric acid production, meanwhile, D. hansenii showed a strong dependence with the initial amount of Mg(2+). Under the best conditions, 28.8 g lactic acid/L (Q(LA) = 0.800 g/L.h, Y(LA/S) = 0.95 g/g), 35.3 g xylitol/L (Q(xylitol) = 0.380 g/L.h, Y(xylitol/S) = 0.69 g/g), and 13.9 g citric acid/L (Q(CA) = 0.146 g/L.h, Y(CA/S) = 0.63 g/g) were obtained. The economic efficiency (E(p/euro)) parameter identify vinasses as a lower cost and more effective nutrient source in comparison to CSL.

Research paper thumbnail of Aromatic Compounds in Wines Produced During Fermentation: Effect of Three Red Cultivars

International Journal of Food Properties, 2007

... Mar Vilanova a * , Sandra Cortés b , José Luis Santiago a , Carmen Martínez a & Esperanza... more ... Mar Vilanova a * , Sandra Cortés b , José Luis Santiago a , Carmen Martínez a & Esperanza Fernández c pages 867-875. ... SAS. 2000. “The SAS System”. In SAS Online Doc. HTML, version 8 , Cary, NC: SAS Institute. View all references]. RESULTS AND DISCUSSION. ...

Research paper thumbnail of Contribution of some grape-derived aromatic compounds to the primary aroma in red wines from cv. Caiño Tinto, cv. Caiño Bravo and cv. Caiño Longo grapes

The Journal of Agricultural Science, 2008