Rooibos launches a wheel with taste

South African researchers have developed a flavour and mouth-feel wheel with 27 descriptive attributes for rooibos - 20 flavour and seven taste and mouth-feel descriptors. This will be a practical tool to facilitate communication among rooibos producers, processors, grading experts, marketers, flavour houses, importers and consumers.

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Under the leadership of Professor Elizabeth Joubert of the Agricultural Research Council, who designed the project proposal together with Stellenbosch University lecturer Nina Muller, Ilona Koch, a masters student at Stellenbosch University and a team of researchers have spent over a year compiling data through numerous experiments with rooibos tea.

"This study was conducted to characterise and quantify the sensory attributes associated with rooibos flavour (taste and aroma) and mouth-feel to paint a more comprehensive picture of what is frequently referred to as 'typical' or 'characteristic' rooibos flavour," said Koch.

Separating the positive from the negative

The researchers studied 69 different rooibos samples originating from 64 different plantations in various production areas. These samples had been graded from A to D, representing the highest to the lowest tea quality respectively.

Through the research, it was uncovered that the positive sensory characteristics such as floral, woody, honey and sweet could be separated from the negative attributes such as green plant, hay-like, dusty and sour. In light of this, the descriptors were grouped according to the positive or negative impact on the quality of the sensory experience.

The wheel will be further updated and refined with samples from another season during the three-year project, which will run until March 2012. It is being funded by the SA Rooibos Council and the Technology and Human Resources for Industry Programme (THRIP) that aims to boost South African industry by supporting research and technology development.