Abstract
In this study, changes in hydrophobic interactions among gluten proteins were analyzed during dough mixing. Size-exclusion high-performance chromatography and two-dimensional fluorescence difference gel electrophoresis were performed on proteins extracted with 1-propanol by weakening the hydrophobic interaction. The amount of proteins extracted with 30% 1-propanol increased from the start of mixing to peak consistency, suggesting that the hydrophobic interactions among the strongly aggregated proteins weakened and resulted in disaggregation. The amount of proteins extracted with 10% 1-propanol decreased during hydration, indicating that these proteins aggregated through relatively weak hydrophobic interactions. The proteins that extractability decreased were mainly low molecular weight glutenin, α-gliadin, and γ-gliadin. The amount of monomeric proteins extracted with 30% 1-propanol decreased after peak consistency. The decreased protein was mainly ω-gliadin, indicating that ω-gliadin aggregated with other proteins through hydrophobic interactions. A front-face fluorescence analysis was performed on the dough with the addition of 8-anilino-1-naphthalenesulfonic acid or thioflavin T. The fluorescence intensity increased as a result of exposure to the hydrophobic groups of the gluten proteins and the formation of protein aggregates during dough mixing. These results indicate the importance of hydrophobic interactions in dough formation.
Highlights
IntroductionPublisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations
In our previous investigation [21], we reported that noncovalent bonds weaken and the molecular size of polymeric proteins decrease during dough mixing, while ω-gliadin aggregates with other proteins through noncovalent bonds
The monomeric proteins and protein aggregates extracted with 10% 1-propanol decreased significantly when water was added in high-protein flour (HF), whereas only the monomeric proteins decreased in low-protein flour (LF)
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. In terms of changes in protein during dough mixing, a decrease in glutenin macropolymer [13,14], a decrease in unextractable polymeric protein (UPP) by sodium dodecyl sulfate (SDS), and a decrease in the molecular weight of UPP have been reported [15]. These results have been attributed to protein depolymerization [13,14,15]. In our previous investigation [21], we reported that noncovalent bonds weaken and the molecular size of polymeric proteins decrease during dough mixing, while ω-gliadin aggregates with other proteins through noncovalent bonds. We used the front-face fluorescence method to examine the changes in the hydrophobic interactions during dough formation
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