Maximising the value of the flavour of Tasmania crops has been the aim of countless programs over the years.
What follows is the latest one, which was triggered by the July column on parsley flavour.
I sent a copy of the column to the head of the Tasmanian Institute of Agriculture, Professor Holger Meinke.
This opened up what is turning out to be a very constructive dialogue with one of his research fellows, Dr Sandra Garland (a public “thank you” to her is warranted – her contributions to this article are in quotes).
“We have all the facilities to undertake trials such as you describe,” Dr Garland said.
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“Not only can we analyse the profile of oils across geographical distributions, we also can undertake aroma profiling of the components as they elute from the chromatography equipment that is employed in the methodology.”
What is emerging is a trial based on parsley growing in pots located on a grid encompassing Tasmania, using some grown in Sydney or Melbourne as controls.
The main flavour chemicals are menthatriene and myristin.
“The ratio of menthatriene and myristin levels alter with the maturity of the inflorescence, such that any comparisons would be across a time series, and the harvest date for each latitude would differ to reflect the impact of climate variation,” Dr Garland said.
At present there are four essential oil distillation plants in Tasmania
- Winnaleah (North East) – Latitude 41.07
- Fingal (Midlands) – 41.44
- Cressy (Midlands) – 41.68
- Ouse (South) – 42.48
This is a good start, albeit with a spread of only 1.4 degrees of latitude.
The experimental grid will extend further north and south, to cover about 3 degrees and more of Tasmania.
“The idea is to identify the components that confer the aromatic impact, which is most likely a suite of chemicals around the terpenic, thymol, citrus taste of 1, 3, 8-p-menthatriene,” Dr Garland said.
“Parsley oils are injected into a specialised piece of equipment that separates the many components that set our taste buds on the path to gourmet delight.
“Flavourists are made comfortable, seated in front of a special ‘sniffing cone’ and as the chemicals come out in a moist gaseous flow, the aroma impressions received are described.
“These descriptions are then related back to the actual chemicals that are identified and measured, simultaneously, by specialised detectors. In this way it may be possible to put a number on parsley flavour.
“Yet the question remains – can we accurately define provenances?
“International markets are keen to leverage these. Any data that provides clear distinctions to this end can contribute to the Tasmanian product fetching a premium.
“As mentioned in Mike’s column, Essential Oils of Tasmania (EOT) has found that Tasmania’s ideal latitude and resultant day length… allows for intensely aromatic and complex, high-quality oils.
“It is that effect of day length and temperature that sets our state apart. The University of Tasmania has growth cabinets that can control the environment of the life cycle of plant, from the levels of carbon dioxide, temperature, water balance and most importantly, day length.
“These would make it possible to track the chemical profile of oils through the growth cycle and relate the flavour of parsley oil to the conditions experienced by plants in the ideal environment.
“When the results from these highly controlled experiments are compared to identical plants (clones) grown in defined bands of latitude from Tasmania to Sydney, the story of why Tasmanian parsley tastes so great can be told in terms of the chemistry behind the flavour.
“This data will make it possible to define flavour provenances.
“In a market where consumers have become discerning in the light of contamination scandals and fraud in product labelling, it will then be up to the grower to use verifiable descriptors of their essential oils to improve their bottom line.”
So there you have it – watch this space.
- Dr Mike Walker is a vegetable grower and long time columnist for Good Fruit & Vegetables magazine. Contact him with feedback: firstname.lastname@example.org