Scientists develop health-boosting purple tea varieties

NARO | HEALTH | TEA VARIETIES 

Scientists at the National Agricultural Research Organisation (NARO) are developing healthy purple tea varieties that have the potential to address the rising prevalence of non-communicable diseases (NCDs). 

According to scientists, the tea varieties have the potential to curtail the rising prevalence of ailments, such as cardio-vascular diseases, cancers, diabetes and chronic respiratory diseases.

There are economic benefits involved, including addressing low tea prices and unemployment.

Improving livelihoods 

The research is being carried out at Rwebitaba Zonal Agricultural Research and Development Institute (Rwebitaba ZARDI) in Kabarole district. 

The institute’s director of research and the principal investigator, Dr Robooni Tumuhimbise, said with support of the science ministry, they are developing healthy-rich tea varieties and value-added tea products for improved livelihoods of Ugandans. Rwebitaba ZARDI is mandated to develop and disseminate appropriate tea technologies for the whole of Uganda. 

“Tea in Uganda is the second largest and highly prioritised export crop after coffee. The country annually earns about $100m (about sh350b) from tea export and the crop provides the much-needed jobs to over 800,000 people,” Tumuhimbise said. 

He added that, despite the economic importance of tea as a source of income and employment, farmers in Uganda still grow colonial-era black tea varieties that are of low quality and value. “As such, quality healthy-rich tea varieties, such as purple tea and value-added tea products that have the potential to address the problems of rising prevalence of NCDs are being explored,” Tumuhimbise said.

Further evaluation need 

He added that through field-based selection from among a collection of about 1,500 tea types at the Rwebitaba’s Tea Research Centre in Fort Portal, and subsequent biochemical laboratory analyses conducted at the NaCRRI-based Bioanalytical and Nutritional Laboratory, Namulonge, five purple tea varieties have been identified, awaiting further evaluation and subsequent release for commercialisation. 

Dr Ephraim Nuwamanya, a biochemist at the National Crops Resources Research Institute (NaCRRI) bioanalytical and nutritional laboratory, Namulonge, said they successfully carried out biochemical profiling to ascertain the quantities of anthocyanins (health-benefiting antioxidants) present in the purple tea varieties. 

“We also looked at their different rates of fermentation. Other aspects of product development, such as market requirements, packaging modules and how they affect the levels of anthocyanins were also studied,” Nuwamanya said. 

He added that purple tea contains significantly higher levels of anthocyanins, compared to green and black tea varieties.

Antioxidant properties 

According to Dr Jessica Nanyunja Sentongo, a nutritionist and the director of Harmony Nutri Foods Ltd, purple tea varieties contain high amounts of anthocyanins that have been reported to lower blood pressure, improve visual acuity, reduce cancer cell development, inhibit tumour formation as well as preventing diabetes. 

She explained that the health-promoting effects of anthocyanins are mainly attributable to their antioxidant properties though other research suggests that other mechanisms of action might be also responsible. 

Tumuhimbise said they received about sh900m from the science ministry for this project for a period of three years. 

He observed the need for more funding from the Government and other stakeholders in order to carry out multi-locational field evaluation to ascertain the adaptability and stability of the purple tea varieties and conforming to the standards that are required for their eventual release. 

“Official variety release and subsequent commercialisation of the purple tea varieties might require as much as six years. 

This also involves the official process of product development, which includes marketing, packaging, and official certification with relevant authorities,” Tumuhimbise said. 

He further clarified that the purple tea varieties are already available with them, but it is the official release procedure required by the agriculture ministry that justifies the long period before commercialisation. 

This story is part of the CABI, SciDev.Net and Robert Bosch Stiftung Script science journalism project