Changes in Protein Non-Covalent Bonds and Aggregate Size during Dough Formation.

Sonoo Iwaki,Katsuyuki Hayakawa,Chikako Otobe,Bin Xiao Fu,Shiro Aono

doi:10.3390/foods9111643

Sonoo Iwaki, Katsuyuki Hayakawa + Show 3 more

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https://doi.org/10.3390/foods9111643

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Abstract

This research investigated changes in the amounts and sizes of monomeric proteins and protein aggregates during dough mixing, with a focus on the contribution of non-covalent bonds in the aggregation of gluten proteins. High protein flour (HF) and low protein flour (LF) were used in this study. As dough mixing progressed from flour to overmixed dough, the total amount of protein aggregates increased while the amount of monomeric protein decreased. Omega-gliadin was the major monomeric protein that decreased in quantity. Interestingly, the amount of larger-sized protein aggregates decreased and that of smaller-sized protein aggregates increased. The amount of gluten protein macro-polymer aggregated through strong non-covalent bonds decreased whereas aggregates formed with weaker non-covalent bonds increased. LF dough behaved similar to HF dough. Large-sized gluten protein aggregates disaggregated due to the weakening of non-covalent bonds and became smaller. Omega-gliadin was incorporated into gluten protein aggregates during dough mixing.

Highlights

Mixing is an important process in bread making
The amount of protein extracted from high protein flour (HF) or low protein flour (LF) with 0.5% Sodium dodecyl sulfate (SDS) buffer is preliminary experiment, experiment, we used 0.5% SDS buffer so that the amount of protein extracted with buffer preliminary containing more than 0.5% SDS did not differ from the amount of protein extracted with 0.5% SDS
Previous publications have shown that protein aggregates in dough became smaller during mixing [23,27,28] but it was difficult to interpret this behavior from size distribution results obtained using chromatography [25]

Summary

Introduction

Mixing is an important process in bread making. Many schematic models have been proposed to describe dough structure [1,2,3,4] and the dough development process [5,6]. MacRitchie [7,8], Belton [9], and Vliet and Hamer [10] proposed conflicting ideas regarding the structural organization of the protein polymers in dough formation and this debate continues to this day [11]. Disulfide bonds and non-covalent bonds are both important for gluten functionality and dough structure. Glutamine facilitates the formation of hydrogen bonds and proline provides hydrophobic interactions. Non-covalent bonds are affected by the presence of salt. Sodium chloride shields the charges on gluten molecules and weakens electrostatic repulsion between protein molecules, resulting in stronger dough [13,14]

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