1:00 pm - 2:00 pm
A graduate exam seminar is a presentation of the student’s final research project for their degree.
This is an ALES MSc Final Exam Seminar by Savanna Won. This seminar is open to the general public to attend.
LC-MS/MS quantitation of bioactive proteins and peptides during sourdough breadmaking
MSc with Dr. Michael Gaenzle and Dr. Jonathan Curtis
Sourdough refers to the fermentation of flour with yeast and lactic acid bacteria and has increasingly captured the interest of industrial and artisanal bakers. It modifies wheat proteins through pH-dependent proteolysis and accumulation of low molecular weight thiols, such as glutathione (GSH). By altering protein structure, sourdough may reduce the bioactivity of wheat allergens, such as alpha-amylase/trypsin inhibitors (ATI). The purpose of this investigation was to develop LC-MS/MS approaches to quantify the ATI protein CM3 and GSH in sourdough during breadmaking to understand how fermentation affects their abundances. GSH and CM3 were extracted from wheat sourdough, MRM-based methods were designed, and the analytes were quantified using LC-QTRAP MS. Doughs were prepared using two wheat cultivars, Red Fife and Brennan, and fermented with Fructilactobacillus sanfranciscensis, F. sanfranciscensis ΔgshR and Latilactobacillus sakei; chemically acidified dough and straight dough served as controls. The abundance of GSH in wheat flour was 35-55 nmol/g flour. Across all treatments, GSH decreased after mixing and after proofing, but increased after baking (P<0.001). CM3 relative abundance remained similar after mixing and after proofing but decreased after baking (P<0.001), regardless of fermentation. This trend was supported by SDS-PAGE analysis of the ATI extracts (P<0.001). Overall, the baking process exerted a greater effect on GSH and CM3 abundance than individual fermentation conditions. Application of LC-MS/MS for analysis of CM3 and GSH will be valuable in elucidating the ability of sourdough to modify wheat allergens for increased tolerability by wheat sensitive consumers.