{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/64708"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/64708","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Fluorometric determination of sulfhydrl plus disulfide as an index to heat treatment of half-and-half","abstract":"A fluorometric technique was developed for measuring -SH + -SS- groups in acid whey from half-and-half at pH 4.6. Measurements were based on proportional decreases (quenching) by these groups of the fluorescence of fluorescein mercuric acetate. Percent quenching was determined with a fluorometer at exciting wavelengths of 415 to 436 nm and 515 nm for measurement. Calculations were made according to the formula: µmoles of -SH + -SS- (X) = percent quenching (Y)/10,256 + 0.00068. Heat treatments of half-and-half between 65.6°C and 82.2°C for 30 min caused progressive decreases in the -SH + -SS- content of the acid whey. A linear regression analysis relating µmoles of -SH + -SS- per ml of whey (Y) on processing temperatures (X) was: Y = 7.69 - 0.089X. There were no additional decreases in these groups by heat treatments between 82.2°C and 93.3°C. After removal of the heat denaturable whey proteins, the acid whey contained 0.44 + 0.04 µmoles of -SH + -SS- per ml of whey or 19.5% of the total in unheated acid whey. Percentage decreases in whey protein nitrogen were closely related to the decreases in -SH + -SS-. The correlation coefficient was 0.99. Fluorometric measurement of -SH + -SS-, however, reflected a wider range of heat treatments than semimicro-Kjeldahl measurement of whey protein nitrogen.","abstract_html":"A fluorometric technique was developed for measuring -SH + -SS- groups in acid whey from half-and-half at pH 4.6. Measurements were based on proportional decreases (quenching) by these groups of the fluorescence of fluorescein mercuric acetate. Percent quenching was determined with a fluorometer at exciting wavelengths of 415 to 436 nm and 515 nm for measurement. Calculations were made according to the formula: µmoles of -SH + -SS- (X) = percent quenching (Y)/10,256 + 0.00068. Heat treatments of half-and-half between 65.6°C and 82.2°C for 30 min caused progressive decreases in the -SH + -SS- content of the acid whey. A linear regression analysis relating µmoles of -SH + -SS- per ml of whey (Y) on processing temperatures (X) was: Y = 7.69 - 0.089X. There were no additional decreases in these groups by heat treatments between 82.2°C and 93.3°C. After removal of the heat denaturable whey proteins, the acid whey contained 0.44 + 0.04 µmoles of -SH + -SS- per ml of whey or 19.5% of the total in unheated acid whey. Percentage decreases in whey protein nitrogen were closely related to the decreases in -SH + -SS-. The correlation coefficient was 0.99. Fluorometric measurement of -SH + -SS-, however, reflected a wider range of heat treatments than semimicro-Kjeldahl measurement of whey protein nitrogen.","abstract_has_math":false,"creators":["Siribunrit, Visit"],"institution":"Virginia Polytechnic Institute and State University","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":[],"committee_members":[],"year":1974,"date_issued":"1974","date_published":"1974","updated_at":"2026-07-22T22:19:51Z","subjects":[],"languages":["en"],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/10919/64708","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.department","label":"Department","values":["Food Science and Technology"]},{"key":"dc:creator","label":"Author","values":["Siribunrit, Visit"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2016-02-01T18:05:44Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2016-02-01T18:05:44Z"]},{"key":"dc:date.issued","label":"Date","values":["1974"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Polytechnic Institute and State University"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.dcmitype","label":"Dc Type Dcmitype","values":["Text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Food Science and Technology"]},{"key":"thesis:degree_level","label":"Degree Level","values":["masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/64708"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["A fluorometric technique was developed for measuring -SH + -SS- groups in acid whey from half-and-half at pH 4.6. Measurements were based on proportional decreases (quenching) by these groups of the fluorescence of fluorescein mercuric acetate. Percent quenching was determined with a fluorometer at exciting wavelengths of 415 to 436 nm and 515 nm for measurement. Calculations were made according to the formula: µmoles of -SH + -SS- (X) = percent quenching (Y)/10,256 + 0.00068. Heat treatments of half-and-half between 65.6°C and 82.2°C for 30 min caused progressive decreases in the -SH + -SS- content of the acid whey. A linear regression analysis relating µmoles of -SH + -SS- per ml of whey (Y) on processing temperatures (X) was: Y = 7.69 - 0.089X. There were no additional decreases in these groups by heat treatments between 82.2°C and 93.3°C. After removal of the heat denaturable whey proteins, the acid whey contained 0.44 + 0.04 µmoles of -SH + -SS- per ml of whey or 19.5% of the total in unheated acid whey. Percentage decreases in whey protein nitrogen were closely related to the decreases in -SH + -SS-. The correlation coefficient was 0.99. Fluorometric measurement of -SH + -SS-, however, reflected a wider range of heat treatments than semimicro-Kjeldahl measurement of whey protein nitrogen."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Fluorometric determination of sulfhydrl plus disulfide as an index to heat treatment of half-and-half"]}]}],"canonical_facts":{"dc:contributor.department":["Food Science and Technology"],"dc:creator":["Siribunrit, Visit"],"dc:date.accessioned":["2016-02-01T18:05:44Z"],"dc:date.available":["2016-02-01T18:05:44Z"],"dc:date.issued":["1974"],"dc:description.abstract":["A fluorometric technique was developed for measuring -SH + -SS- groups in acid whey from half-and-half at pH 4.6. Measurements were based on proportional decreases (quenching) by these groups of the fluorescence of fluorescein mercuric acetate. Percent quenching was determined with a fluorometer at exciting wavelengths of 415 to 436 nm and 515 nm for measurement. Calculations were made according to the formula: µmoles of -SH + -SS- (X) = percent quenching (Y)/10,256 + 0.00068. Heat treatments of half-and-half between 65.6°C and 82.2°C for 30 min caused progressive decreases in the -SH + -SS- content of the acid whey. A linear regression analysis relating µmoles of -SH + -SS- per ml of whey (Y) on processing temperatures (X) was: Y = 7.69 - 0.089X. There were no additional decreases in these groups by heat treatments between 82.2°C and 93.3°C. After removal of the heat denaturable whey proteins, the acid whey contained 0.44 + 0.04 µmoles of -SH + -SS- per ml of whey or 19.5% of the total in unheated acid whey. Percentage decreases in whey protein nitrogen were closely related to the decreases in -SH + -SS-. The correlation coefficient was 0.99. Fluorometric measurement of -SH + -SS-, however, reflected a wider range of heat treatments than semimicro-Kjeldahl measurement of whey protein nitrogen."],"dc:description.degree":["Master of Science"],"dc:format.mimetype":["application/pdf"],"dc:identifier.uri":["http://hdl.handle.net/10919/64708"],"dc:language.iso":["en"],"dc:publisher":["Virginia Polytechnic Institute and State University"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:title":["Fluorometric determination of sulfhydrl plus disulfide as an index to heat treatment of half-and-half"],"dc:type":["Thesis"],"dc:type.dcmitype":["Text"],"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":"2026-07-22T22:19:51Z"}