A soothing cup of rice? Chinese scientists create grain with health benefits of tea

 

In a study, the team engineered ‘tea rice’ that has been fortified with the antioxidant compounds in green tea – without the caffeine

Chinese scientists have engineered the first “tea rice” enriched with the antioxidant compounds that make green tea a health-boosting drink.

The rice has been fortified with the micronutrient catechin, and the researchers behind it say it can provide the health benefits of tea without any side effects from caffeine.

“Catechins, as key antioxidant components in tea plants with high content, offer certain benefits to human health,” the team said in a paper published in the peer-reviewed Plant Biotechnology Journal in March.

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Catechin flavonoids are a type of polyphenol – micronutrients that occur naturally in plants – shown to have antibacterial, anti-inflammatory, anticancer and cardioprotective properties.

Catechins are thought to play a role in regulating blood pressure, aiding in weight loss, and lowering the risk of cardiovascular disease.

“These essential flavonoid phytonutrients are renowned for their pivotal role in bestowing the unique health benefits associated with tea plant consumption,” the team said.

Catechins make up around 15 to 30 per cent of the dry weight of tea, with particularly high levels found in green tea as it does not undergo the same oxidation process that black tea does during processing.

While green tea contains these beneficial compounds, it also contains caffeine, which can cause people to experience symptoms like insomnia and heart palpitations, particularly when consumed in large amounts.

“Therefore, there is an impetus to develop a ‘tea rice’ with a high content of catechins in the endosperm,” according to the researchers from Hainan University, Yazhouwan National Laboratory and Huazhong Agricultural University.

Low expression of the flavonoid pathway genes in most cultivated rice plants results in low flavonoid content in the endosperm – or the inside of a rice grain – making them an “optimal candidate for biofortification efforts”, the paper said.

There has been a trend of engineering value-added crops in recent years, including the development of meat-infused rice, or rice fortified with nutrients like the heart-healthy coenzyme Q.

To develop a “tea rice” with a high content of catechins in the endosperm, the team harnessed genetic engineering to introduce genes involved in catechin synthesis from the tea plant into a variety of rice.

Testing confirmed that the edited rice had “significantly improved antioxidant capabilities” compared to the original rice cultivar.

It also showed elevated levels of various metabolites, indicating that flavonoid synthesis may activate key metabolic pathways and provide an environment that promotes the synthesis of vitamin B.

The resulting transgenic rice grains were smaller than those of the original rice cultivar, leading to a reduced yield.

“The catechin-fortified rice in this study can be used as a functional grain to promote health,” the team said in the paper.