{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/46209"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/46209","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"The effects of different processing parameters (cold soak and percent alcohol (v/v) at dejuicing) on the concentrations of grape glycosides and glycoside fractions and glycosidase activities in selected yeast and lactic acid bacteria","abstract":"Grape-derived aroma and flavor precursors exist partially as non-volatile, sugar-bound glycosides. Hydrolysis of these compounds may modify sensory attributes and potentially enhance wine quality. Cold soak (prefermentation skin contact) at two temperatures and alcohol content (%, v/v) at dejuicing were monitored to determine effects on Cabernet Sauvignon glycoside concentration. Total, phenolic-free, and red-free glycoside concentrations were estimated by the quantification of glycosyl-glucose. Cold soak (5 days at 10° C) increased total glycosides by 77%, red-free glycosides by 80%, and phenolic-free glycosides by 96%. Ambient soak (3 days at 20° C) enhanced color extraction, and increased total glycosides by 177%, red-free glycosides by 144%, and phenolic-free glycosides by 106%. Wines produced by early pressing (10% sugar) had 25% more total and red-free glycosides than late press (0.25% sugar). After post-fermentation malolactic fermentation, total glycosides were 14% lower and phenolic-free glycosides were 35% lower. In a second study, the activities of a-L-arabinofuranosidase, b-glucosidase, and a-L-rhamnoyranosidase were determined in model systems for thirty-two strains of yeasts belonging to the following genera: Aureobasidium, Candida, Cryptococcus, Hanseniaspora, Hansenula, Kloeckera, Metschnikowia, Pichia, Saccharomyces, Torulaspora, and Brettanomyces (10 strains); and seven bacteria (Leuconostoc oenos strains). Only one Saccharomyces strain exhibited -glucosidase activity, but several non-Saccharomyces yeast species had substantial production. Aureobasidium pullulans hydrolyzed a-L-arabinofuranoside, b-glucoside, and a-L-rhamnoyranoside. Eight Brettanomyces strains had -glucosidase activity. Location of enzyme activity was determined for those species with enzymatic activity. The majority of -glucosidase was located in the whole cell fraction (66%), followed by the permeabilized fraction (35%), and extracellular production (2%). Aureobasidium pullulans was also capable of hydrolyzing grape glycosides.","abstract_html":"Grape-derived aroma and flavor precursors exist partially as non-volatile, sugar-bound glycosides. Hydrolysis of these compounds may modify sensory attributes and potentially enhance wine quality. Cold soak (prefermentation skin contact) at two temperatures and alcohol content (%, v/v) at dejuicing were monitored to determine effects on Cabernet Sauvignon glycoside concentration. Total, phenolic-free, and red-free glycoside concentrations were estimated by the quantification of glycosyl-glucose. Cold soak (5 days at 10° C) increased total glycosides by 77%, red-free glycosides by 80%, and phenolic-free glycosides by 96%. Ambient soak (3 days at 20° C) enhanced color extraction, and increased total glycosides by 177%, red-free glycosides by 144%, and phenolic-free glycosides by 106%. Wines produced by early pressing (10% sugar) had 25% more total and red-free glycosides than late press (0.25% sugar). After post-fermentation malolactic fermentation, total glycosides were 14% lower and phenolic-free glycosides were 35% lower. In a second study, the activities of a-L-arabinofuranosidase, b-glucosidase, and a-L-rhamnoyranosidase were determined in model systems for thirty-two strains of yeasts belonging to the following genera: Aureobasidium, Candida, Cryptococcus, Hanseniaspora, Hansenula, Kloeckera, Metschnikowia, Pichia, Saccharomyces, Torulaspora, and Brettanomyces (10 strains); and seven bacteria (Leuconostoc oenos strains). Only one Saccharomyces strain exhibited -glucosidase activity, but several non-Saccharomyces yeast species had substantial production. Aureobasidium pullulans hydrolyzed a-L-arabinofuranoside, b-glucoside, and a-L-rhamnoyranoside. Eight Brettanomyces strains had -glucosidase activity. Location of enzyme activity was determined for those species with enzymatic activity. The majority of -glucosidase was located in the whole cell fraction (66%), followed by the permeabilized fraction (35%), and extracellular production (2%). Aureobasidium pullulans was also capable of hydrolyzing grape glycosides.","abstract_has_math":false,"creators":["McMahon, Heather"],"institution":"Virginia Tech","degree_name":"Master of Science","degree_level":"masters","degree_discipline":"Food Science and Technology","degree_department":"Food Science and Technology","school":null,"contributors":[],"advisors":[],"committee_chairs":["Zoecklein, Bruce W."],"committee_members":["Fugelsang, Kenneth","Claus, George William","Eigel, William N. III"],"year":1998,"date_issued":"1998-12-03","date_published":"1998-12-03","updated_at":"2026-07-22T22:19:16Z","subjects":["Cabernet Sauvignon","cold soak","glycosidases","glycosides","yeast"],"languages":[],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-121498-094044"],"render_values":[{"text":"etd-121498-094044","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/46209","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Zoecklein, Bruce W."]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Fugelsang, Kenneth","Claus, George William","Eigel, William N. 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Hydrolysis of these compounds may modify sensory attributes and potentially enhance wine quality. Cold soak (prefermentation skin contact) at two temperatures and alcohol content (%, v/v) at dejuicing were monitored to determine effects on Cabernet Sauvignon glycoside concentration. Total, phenolic-free, and red-free glycoside concentrations were estimated by the quantification of glycosyl-glucose. Cold soak (5 days at 10° C) increased total glycosides by 77%, red-free glycosides by 80%, and phenolic-free glycosides by 96%. Ambient soak (3 days at 20° C) enhanced color extraction, and increased total glycosides by 177%, red-free glycosides by 144%, and phenolic-free glycosides by 106%. Wines produced by early pressing (10% sugar) had 25% more total and red-free glycosides than late press (0.25% sugar). After post-fermentation malolactic fermentation, total glycosides were 14% lower and phenolic-free glycosides were 35% lower. In a second study, the activities of a-L-arabinofuranosidase, b-glucosidase, and a-L-rhamnoyranosidase were determined in model systems for thirty-two strains of yeasts belonging to the following genera: Aureobasidium, Candida, Cryptococcus, Hanseniaspora, Hansenula, Kloeckera, Metschnikowia, Pichia, Saccharomyces, Torulaspora, and Brettanomyces (10 strains); and seven bacteria (Leuconostoc oenos strains). Only one Saccharomyces strain exhibited -glucosidase activity, but several non-Saccharomyces yeast species had substantial production. Aureobasidium pullulans hydrolyzed a-L-arabinofuranoside, b-glucoside, and a-L-rhamnoyranoside. Eight Brettanomyces strains had -glucosidase activity. Location of enzyme activity was determined for those species with enzymatic activity. The majority of -glucosidase was located in the whole cell fraction (66%), followed by the permeabilized fraction (35%), and extracellular production (2%). Aureobasidium pullulans was also capable of hydrolyzing grape glycosides."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:title","label":"Title","values":["The effects of different processing parameters (cold soak and percent alcohol (v/v) at dejuicing) on the concentrations of grape glycosides and glycoside fractions and glycosidase activities in selected yeast and lactic acid bacteria"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Zoecklein, Bruce W."],"dc:contributor.committeemember":["Fugelsang, Kenneth","Claus, George William","Eigel, William N. III"],"dc:contributor.department":["Food Science and Technology"],"dc:creator":["McMahon, Heather"],"dc:date.accessioned":["2014-03-14T21:51:25Z"],"dc:date.available":["2014-03-14T21:51:25Z","1999-12-16"],"dc:date.issued":["1998-12-03"],"dc:description.abstract":["Grape-derived aroma and flavor precursors exist partially as non-volatile, sugar-bound glycosides. Hydrolysis of these compounds may modify sensory attributes and potentially enhance wine quality. Cold soak (prefermentation skin contact) at two temperatures and alcohol content (%, v/v) at dejuicing were monitored to determine effects on Cabernet Sauvignon glycoside concentration. Total, phenolic-free, and red-free glycoside concentrations were estimated by the quantification of glycosyl-glucose. Cold soak (5 days at 10° C) increased total glycosides by 77%, red-free glycosides by 80%, and phenolic-free glycosides by 96%. Ambient soak (3 days at 20° C) enhanced color extraction, and increased total glycosides by 177%, red-free glycosides by 144%, and phenolic-free glycosides by 106%. Wines produced by early pressing (10% sugar) had 25% more total and red-free glycosides than late press (0.25% sugar). After post-fermentation malolactic fermentation, total glycosides were 14% lower and phenolic-free glycosides were 35% lower. In a second study, the activities of a-L-arabinofuranosidase, b-glucosidase, and a-L-rhamnoyranosidase were determined in model systems for thirty-two strains of yeasts belonging to the following genera: Aureobasidium, Candida, Cryptococcus, Hanseniaspora, Hansenula, Kloeckera, Metschnikowia, Pichia, Saccharomyces, Torulaspora, and Brettanomyces (10 strains); and seven bacteria (Leuconostoc oenos strains). Only one Saccharomyces strain exhibited -glucosidase activity, but several non-Saccharomyces yeast species had substantial production. Aureobasidium pullulans hydrolyzed a-L-arabinofuranoside, b-glucoside, and a-L-rhamnoyranoside. Eight Brettanomyces strains had -glucosidase activity. Location of enzyme activity was determined for those species with enzymatic activity. The majority of -glucosidase was located in the whole cell fraction (66%), followed by the permeabilized fraction (35%), and extracellular production (2%). Aureobasidium pullulans was also capable of hydrolyzing grape glycosides."],"dc:description.degree":["Master of Science"],"dc:identifier.other":["etd-121498-094044"],"dc:identifier.uri":["http://hdl.handle.net/10919/46209"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:subject":["Cabernet Sauvignon","cold soak","glycosidases","glycosides","yeast"],"dc:title":["The effects of different processing parameters (cold soak and percent alcohol (v/v) at dejuicing) on the concentrations of grape glycosides and glycoside fractions and glycosidase activities in selected yeast and lactic acid bacteria"],"dc:type":["Thesis"],"thesis:degree_discipline":["Food Science and Technology"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:19:16Z"}