Macrozamia Sarcotesta (by-yu): a traditional food of the Noongar of Southwestern Australia

Published: September, 2010

Mark Cornish BSc (Hon), freelance science communicator

The traditional Noongar people of south-western Australia developed over many thousands of years an effective means of detoxifying and enhancing the nutrient food value of the bright red outer seedcoat of the toxic Macrozamia plant through a process of soaking and burying the seed in an anaerobic environment for several weeks. It would seem that the toxin (macrozamin) diminishes and is potentially eliminated as a result of this unique controlled fermentation and storage process – the end product being an extremely nutritious and favoured food known as by-yu (or kwineen) rich in oil and carotene.

Partially opened Macrozamia fraseri displaying its seeds.
The ripe seeds of Macrozamia fraseri (Photo by Barb Dobson)

Research anthropologists Ken Macintyre and Dr Barb Dobson have replicated the now-forgotten traditional techniques formerly used by Noongars to process the Macrozamia sarcotesta (seed coat). Macintyre and Dobson’s replicative experiments, conducted over a period of three years, are based on the descriptions of indigenous techniques provided by the early explorers and settlers.

After soaking, the Macrozamia fruit is buried in dry sand in a Xanthorrhea-lined pit. Photo by Ken Macintyre.

Macintyre points out that many of these accounts were based on second-hand information rather than first hand observations.

Dobson, also highly sceptical as to whether any of these early reports were actually based on first-hand observations, comments:

‘It would seem that the harvesting and processing of by-yu was an exclusively female activity. It is my view that the male explorers and recorders tended to rely on anecdotal and colonial hearsay rather than their own personal observations of this remarkably ancient, effective and unique sarcotesta treatment process.’

A recent chemical analysis of the food value of processed Macrozamia fraseri sarcotesta, carried out by the ChemCentre WA on raw and processed specimens provided by Macintyre and Dobson showed that the unfermented sarcotesta of M. fraseri contained a very high fat content (37%, 18.2) which increased to approximately 42% (22.2) after processing, thereby further enhancing its food value.

Processed, cleaned Macrozamia seed. Photo by Ken Macintyre.

It is not generally recognised in the Western scientific community that Macrozamia sarcotesta has the status equivalent to that of an oil seed. Yet the seedcoat’s oiliness was a well-recognised feature and a much-relished traditional food item during the late autumn/early winter period. By-yu was consumed during the season known as geran (also popularly known as jeran) which is a descriptor meaning fat, oil or grease, which in this context denotes the time of the year (April-May) when the fat cycle was particularly important to the diet of traditional Noongar hunter-gatherers.

Macintyre comments that ‘this high fat food would have played an essential part in the build-up of body fats and vitamins in preparation for the inclement and lean winter months.’

Macintyre reckons that the early Anglo-European recorders (through to contemporary anthropologists and archaeologists) have tended to focus almost exclusively on the indigenous processing of Macrozamia as a means of removing toxins. ‘This may be important but what has not been recognised is the highly nutritional value of the fermented red seedcoat which was the only part of the Macrozamia seed eaten by the indigenous people of southwestern Australia.

This is contrary to the practise of indigenous populations in Eastern and Northern Australia who traditionally consumed only the processed carbohydrate-rich kernel, discarding the sarcotesta.

Dobson remarks that this practice makes the traditional Noongar inhabitants of southwestern Australia unique as ‘they seem to be the only indigenous population in the world known to have processed the Macrozamia sarcotesta to provide a rich source of edible fats.’

‘I’m puzzled as to why the Macrozamia sarcotesta was not more widely used by other Aboriginal groups given its nutritive qualities’ queried Dobson.

And how does it taste? ‘Rich and oily, somewhat of an acquired taste’ commented Macintyre. However, he cautions people not to eat Macrozamia sarcotesta or seeds because even after processing they may contain residual toxicity or rancidity.



Mark Cornish BSc (Hon), freelance science communicator

September 2010