“Food is the paramount necessity of the people”. Recently, a research team jointly led by the Institute of Agro-Food Science and Technology (IAFST) of the Chinese Academy of Agricultural Sciences (CAAS) and international collaborators has systematically uncovered the micro- and meso-scale mechanisms through which wheat genotype, irrigation conditions, storage methods, and milling processes influence dough rheological properties and end-product quality. This study for the first time identifies the ratio of intermolecular disulfide bonds to hydrogen bonds in proteins as a key regulatory index, providing new theoretical support for the breeding of high-quality, specialized wheat varieties and the precise processing of flour-based products. Relevant findings have been published in Food Chemistry, a leading international journal in the food science field.
The texture, elasticity, and mouthfeel of flour-based products such as bread, noodles, and steamed buns depend on the three-dimensional network structure formed by gluten proteins in wheat flour. However, how multiple factors – during breeding, cultivation, storage, and processing – affect intermolecular protein interactions, thereby determining dough strength, extensibility, and water-holding capacity. They have long been a focus and challenge for both academic and industrial communities. To unravel this complex process, the research team conducted systematic studies using representative wheat genotypes.
The results show that strong-gluten wheat varieties carrying the “5+10” subunit have higher protein and disulfide bond contents, producing dough with better elasticity and higher consistency during Farinograph mixing. However, their gluten network is overly dense, leading to relatively weak water-holding capacity. Meanwhile, non-irrigated conditions during the growing season promote the formation of more disulfide bonds in wheat during the grain filling stage, enabling protein “pre-aggregation” that tightens the dough protein network – requiring more mixing energy in subsequent dough preparation.
Regarding storage methods, anaerobic storage at 4℃ significantly inhibits excessive disulfide bond formation while promoting hydrogen bond accumulation compared to ambient temperature aerobic storage. Hydrogen bonds contribute to the extension of the gluten network and enhance water-holding capacity. The researchers also found that even within the same batch of wheat, flour properties exhibit gradient differences due to variations in protein composition and state across different parts of the wheat kernel.
A breakthrough of this study is the proposal of a quantifiable key index for evaluating protein network aggregation – the ratio of disulfide bonds to hydrogen bonds. Figuratively, disulfide bonds act like sturdy steel nails determining the strength of the dough network, while hydrogen bonds function as flexible Velcro influencing the network’s elasticity and water-holding capacity. The study demonstrates a significant positive correlation between this ratio and the peak consistency of dough during Farinograph mixing: a higher ratio indicates tighter protein aggregation and stronger dough strength. In contrast, gluten water-holding capacity shows a negative correlation with the energy required to reach the Farinograph mixing peak.
Zhang Bo, a researcher at IAFST-CAAS, stated that the study reveals the core mechanism of dough quality formation from the micro – and meso-scales of protein interactions, holding important guiding significance for industrial practice. In breeding, genotypes regulating key interaction ratios can be targeted selected. In cultivation, water management can be optimized to balance yield and protein quality. In storage, transportation, and processing, flour processing properties can be precisely regulated through controlled storage conditions and scientific flour blending – ultimately achieving standardized production of high-quality flour-based products.