Warming climate may change protein composition of wheat, study suggests

Higher levels of carbon dioxide in the atmosphere can significantly alter the protein composition of wheat, affecting not only baking quality but also the tolerability of wheat products, a new study has found.

Findings published in the journal Food Chemistry suggest that crop adaptation to climate change should focus not only on high yields but also on quality characteristics such as protein composition.

Researchers, led by the Leibniz Institute for Food Systems Biology at the Technical University of Munich in Germany, said that globally, carbon dioxide (CO2) levels have increased from 340 parts per million in 1980 to about 425 parts per million in 2024.

Wheat, one of the world’s most important staple foods, will also grow under significantly higher CO₂ concentrations in the future, which could reach 600 parts per million by 2050, they said.

The team grew 10 cultivated varieties of winter wheat under realistic growing and environmental conditions. Some plants were exposed to an elevated CO₂ concentration of 546 parts per million, while others grew under current CO₂ conditions.

After harvest, the researchers analysed the composition of wheat proteins in the various grain samples using a high-resolution mass spectrometric method they had developed. They focused on proteins such as amylase/trypsin inhibitors, puroindolines and gluten proteins, as well as peptides associated with coeliac disease.

Overall, the content of amylase/trypsin inhibitors increased under elevated CO₂ conditions, while that of puroindolines, gluten proteins and certain coeliac disease-active peptides — which may be produced from gluten proteins during digestion — decreased. The increased levels of amylase/trypsin inhibitors (ATIs) could negatively affect human health.

“However, the extent of these changes depended largely on the specific wheat cultivar,” Sabrina Geisslitz, principal investigator and research associate at the Leibniz Institute, said.

“Our results also showed that the reduced concentration of gluten proteins was associated with poorer baking quality,” Geisslitz said.

Katharina Scherf, head of the food biopolymer chemistry research group at the Leibniz Institute and professor of food biopolymer systems at the TUM School of Life Sciences, added: “The observed changes in amylase/trypsin inhibitors and certain coeliac disease-active peptides could also be relevant in the long term for wheat-related diseases. However, further studies are needed to clarify the actual biological and immunological significance of these differences.”

The study’s results underscore the importance of identifying and breeding cultivated varieties of wheat that maintain high baking quality even under increasing CO₂ concentrations, while containing as few potentially intolerable proteins as possible, the researchers said.

“Rising atmospheric CO₂ concentrations may alter the protein composition of wheat and thereby affect grain quality,” the authors wrote.

“The findings highlight the importance of identifying cultivars (cultivated varieties) with low levels of ATIs and coeliac disease-active peptides while maintaining good baking quality under rising CO₂,” they said.