PROTEOMIC INSIGHTS INTO BREAD-MAKING: FERMENTATION EFFECTS ON WHEAT PROTEIN PROFILES

Common wheat (T. aestivum) dominates cultivated wheat at around 95%. Gluten proteins confer distinct rheological properties, are the main responsible for viscoelasticity, facilitate dough leavening and structural maintenance in breadmaking. Advanced proteomic techniques like UHPLC-MS/MS aid in deciphering protein contributions to end product quality and identifying optimal wheat cultivars for baking. This research explored how S. cerevisiae fermentation affects protein profiles in breads from two wheat flours: ORS Agile (bread/improver wheat) and ORS Vintecinco (biscuit wheat). Proteins were categorized by solubility (AG, Gli, reduced Glu) and assessed using RP-HPLC and Kjeldahl methods. Proteomic data was obtained by NanoLC-MS/MS analysis on a Q Exactive Plus Orbitrap, processed via MaxQuant using UniprotKB Triticum database. Total protein ranged from 8.2% to 12.9%. ORS Agile had lower extractability (62%) than ORS Vintecinco (98%). Both genotypes showed reduced AG and Gli, and increased Glu levels in breads. Glu increase was more significant in ORS Vintecinco (~200%) than ORS Agile (~54%). Impact during breadmaking was notable for α-gliadin and γ-gliadin, with reduced expression intensities after kneading, dough formation and fermentation. LMW-GS contents increased after processing, while HMW-glutenins exhibited variable behavior depending on the analyzed genotype. Considering proteomic analysis, 250 proteins were evaluated (187 for ORS Agile, 122 for ORS Vintecinco, 59 common). Distinctive proteins could serve as potential biomarkers for flour composition and bread origin. Proteomic analysis unveiled composition differences among products from contrasting flour samples. Discrepancies in structure and composition of gluten proteins between genotypes could influence the susceptibility to modifications induced by processing. ORS Vintecinco was notably more affected by processing when compared to ORS Agile. The hypothesis to explain this finding is that weak wheat flour may be more inclined to suffer changes in gluten content during processing due to its lower gluten content when compared to strong wheat flour, facilitating protein polymerization.