Impact of cocoa (Theobroma cacao L.) fermentation on composition and concentration of polyphenols: Development of fermentation model system and utilization of yeast starter cultures

Simple item page
dc.contributor.authorLee, Andrew H.en
dc.contributor.committeechairStewart, Amanda C.en
dc.contributor.committeememberOgejo, Jactone Arogoen
dc.contributor.committeememberNeilson, Andrew P.en
dc.contributor.committeememberO'Keefe, Sean F.en
dc.contributor.departmentFood Science and Technologyen
dc.date.accessioned2019-03-23T06:00:44Zen
dc.date.available2019-03-23T06:00:44Zen
dc.date.issued2017-09-28en
dc.description.abstractConsumption of cocoa and dark chocolate products has been associated with positive health outcomes including reduced onset of cardiovascular disease, inflammation, diabetes, obesity, and platelet disorders. Cocoa polyphenols, putatively responsible for these beneficial activities, are highly impacted by cocoa variety, agronomic effects and processing history. However, the difference in polyphenol concentration and composition between cocoa products originating from different hybrid clones (selected for high yield) or from different fermentation conditions is not fully understood. Detailed polyphenol characterization including determination of total polyphenol and total procyanidin concentrations, and qualitative and quantitative analysis of (mean) degree of polymerization was conducted. Significant differences in total polyphenol and procyanidin concentrations were observed between five genetic clones grown by the USDA-ARS Cocoa Germplasm Repository located in Mayagüez, Puerto Rico. To facilitate cocoa fermentation research in laboratories distant from cocoa harvesting sites, a laboratory-scale cocoa fermentation model system was developed in this study. This model system used dried, unfermented, cocoa beans and simulated pulp medium as the starting material. The model system supported growth of the essential succession of cocoa fermenting microorganisms and generated similar chemical changes to those observed in on-farm cocoa fermentation. Using this model system, the impact of inoculation with proprietary yeast strains Saccharomyces cerevisiae Lev F and Saccharomyces cerevisiae Lev B on cocoa polyphenol concentration and composition was evaluated. Inoculation with both yeast strains resulted in increased fermentation rate and Lev B inoculation resulted in higher total polyphenol and procyandin contents at the end of fermentation. Overall, the present work addressed the influence of cocoa variety selection and fermentation process conditions on the composition and concentration of polyphenols. These findings will contribute to continued efforts to develop cocoa products with optimized bioactivity and maximum disease preventative effects.en
dc.description.degreePHDen
dc.format.mediumETDen
dc.identifier.othervt_gsexam:12630en
dc.identifier.urihttp://hdl.handle.net/10919/88515en
dc.publisherVirginia Techen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectCocoa fermentationen
dc.subjectlaboratory model systemen
dc.subjectyeast starter inoculationen
dc.subjectmicrobial identificationen
dc.subjectmetabolite analysis (HPLC)en
dc.subjectvolatile compound analysis (GC-MS)en
dc.subjecttotal polyphenolen
dc.subjecttotal procyanidinen
dc.subjectdegree of polymerizationen
dc.titleImpact of cocoa (Theobroma cacao L.) fermentation on composition and concentration of polyphenols: Development of fermentation model system and utilization of yeast starter culturesen
dc.typeDissertationen
thesis.degree.disciplineFood Science and Technologyen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePHDen

Files

Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
Lee_AH_D_2017.pdf
Size:
32.66 MB
Format:
Adobe Portable Document Format
Download

Collections

Doctoral Dissertations