Researchers at the Riddet Institute in Palmerston North have discovered that taewa have different attributes to modern potato varieties, which makes them useful for developing new food products.

A team of researchers led by Dr Jaspreet Singh at Riddet Institute has been studying the characteristics of taewa. They selected four different taewa cultivars: Karuparera, Tūtaekurī, Huakaroro and Moemoe. They chose these – from 30 possible cultivars – for their differences in size, shape and colour and used the modern potato Nadine for comparison.

Taewa characteristics

Taewa tubers are colourful, irregular shapes with deeply indented eyes and are often quite small. Many varieties have coloured skin and flesh. They look very different from modern potatoes. While their shape may not be very appealing to all consumers, they have many properties that offer opportunities for value-added products with wide consumer appeal.

Aesthetic value

The colour of the skin and flesh of taewa cultivars varies widely. The cultivars used in the research have either purple or yellow skin with purple, yellow or white flesh, whereas modern potato cultivars are usually white or cream in colour. The rich colours of taewa could add a visual or aesthetic value to any new food products made from them. Would you like to eat purple crisps?

The Tūtaekurī cultivar has particularly high levels of a purple pigment in its skin and flesh. Researchers can extract this pigment and use it as a natural food colour or antioxidant in food or pharmaceutical products.

Nutritional benefits

Testing of the taewa cultivars showed that they contain lots of nutrients. Overall, taewa have more antioxidants than modern Nadine potatoes (for example, 6-10 times more in the case of Tūtaekurī). Antioxidants are thought to protect cells from damage and may reduce the risk of cancer and slow the effects of ageing. Taewa are also rich in essential amino acids, minerals and anthocyanins. The skin of all the cultivars has higher protein, fat, minerals and dietary fibre than the flesh. All four cultivars showed significant nutritional advantages over the modern potato, Nadine.

Cultural significance

The cultural significance of taewa as an indigenous food in New Zealand offers unique marketing opportunities for value-added food products aimed at niche markets.

Functional properties

Potatoes are very high in starch, which has many uses in industrial food applications. Researchers tested the functional properties of starch and flour from taewa to find out how they could be used in new food products.

The results of the research showed all four taewa starches had quite similar properties and functional behaviour to the Nadine. Flours prepared from some taewa cultivars showed improved functional properties than Nadine flour. Therefore, taewa four and starch could be used for various food applications, with the added advantage of their aesthetic value and nutritional benefits.

Researchers at the Riddet Institute have also found that starch properties changed as taewa tubers were stored. They are comparing the taewa varieties to see whether storing might be useful for different end products.

There is huge demand for healthy food with good functional properties all over the world, and taewa have the potential to meet this demand. Find out more about developing novel foods from taewa.

    Published 15 June 2009