Unlocking the potential: Removing bitterness from rapeseed paves the way for a sustainable protein source in the green transition

A groundbreaking study recently published in the prestigious journal Nature by researchers at the University of Copenhagen has made significant progress in addressing the long-standing issue of rapeseed’s bitterness and its unsuitability for human consumption. Rapeseed, which currently accounts for half of the plant proteins produced in the European Union, has primarily been utilized for oil production and animal feed due to its bitter taste and potential health risks.

Denmark, known for its picturesque yellow rapeseed fields spanning over 200,000 hectares, has seen the crop cultivated for various purposes, except as a direct food source for humans. The plant’s bitter compounds serve as natural defense mechanisms against diseases and herbivores, effectively safeguarding the crop. However, these compounds render rapeseed inedible to humans.

The research team from the University of Copenhagen’s Department of Plant and Environmental Sciences focused on understanding the proteins responsible for storing the bitter substances in the seeds of thale cress, a closely related model plant. By identifying these proteins, they have unlocked the potential to eliminate the bitter taste from rapeseed. This breakthrough could revolutionize the use of rapeseed as a protein source, supporting the ongoing green transition.

Professor Barbara Ann Halkier, the lead researcher of the study, emphasizes the urgent need for reducing meat consumption and incorporating more plant-based foods in light of the climate crisis. Rapeseed, with its immense protein potential, could play a vital role in this transition. The recent findings represent a critical advancement in harnessing the full potential of rapeseed as a sustainable plant protein source.

By addressing the bitterness issue, researchers have opened up a world of possibilities for rapeseed utilization, catering to the rising demand for plant-based proteins. This development not only benefits human nutrition but also aligns with the imperative to combat climate change and promote a greener future.

Substances in wasabi and mustard are gone

Glucosinolates, the bitter defensive compounds found in rapeseed, are renowned for their spicy flavors reminiscent of mustard and wasabi. Consequently, the utilization of rapeseed cake, the residual product obtained after oil extraction, has been limited primarily to animal feed, despite its remarkable protein content ranging from 30% to 40%.

In a significant advancement, the University of Copenhagen researchers successfully tackled the issue of bitterness by pinpointing three proteins responsible for transporting these defensive substances into the plant’s seeds. With this newfound knowledge, a technique called “transport engineering” can be employed to eliminate these proteins, thereby preventing the accumulation of glucosinolates in the seeds. Notably, the defensive compounds remain present in other parts of the plant, enabling it to continue protecting itself.

Dr. Deyang Xu, the lead author of the study, explains that their research reveals the existence of a cellular hub, resembling an umbilical cord, between the seeds and the surrounding fruit shell. This structure acts as a production site for glucosinolates, which ultimately find their way into the seeds. As plants are firmly rooted in the soil and unable to flee from danger, they rely on a diverse array of defensive substances to defend against diseases and herbivores. The discovery of these transport proteins has provided a means to eliminate the bitter substances from the seeds while allowing the plant to maintain its defense mechanisms.

A breakthrough 10 years in the making

The effectiveness of the method developed by the researchers has been demonstrated in thale cress (Arabidopsis thaliana), a plant widely used as a model organism for studying various biological processes, including those related to rapeseed. Now, the team is focused on the crucial next step of transferring their findings from Arabidopsis to rapeseed, which shares a close botanical relationship with the model plant.

Dr. Xu emphasizes the ongoing efforts, stating, “Our current endeavor involves applying our results from Arabidopsis to the rapeseed plant, which is the natural progression of our research.”

The breakthrough achievement resulting from this study is the culmination of extensive research facilitated by a generous 10-year grant from the Danish National Research Foundation. This grant enabled the researchers at the DynaMo Center, housed within the Department of Plant and Environmental Sciences at the Faculty of Science, to dedicate themselves to this project over an extended period.

Professor Barbara Ann Halkier expresses the significance of the long-term grant, highlighting its pivotal role in the team’s ability to attain this significant research outcome. The grant not only provided the necessary financial support but also granted the researchers ample time to delve deep into the intricacies of the study, ultimately yielding fruitful results.

The combination of focused dedication and substantial resources has proven instrumental in the successful advancement of their research, underscoring the importance of long-term funding for transformative scientific breakthroughs.

Source: University of Copenhagen

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