Fruit genetics set to create new natural flavours

New Zealand plant research institute HortResearch says its scientists can now accurately determine which genes create the individual flavours and fragrances found in fruits and flowers.

Their breakthrough findings will allow flavour houses to recreate natural flavour compounds using traditional fermentation techniques, rather than having to resort to chemical synthesis or costly extraction processes.

"We were interested in finding out which genes make flavour and aroma compounds so that breeders know how to maintain them," explained Dr Richard Newcomb, industrial biotechnology scientist at HortResearch.

"We used microarrays to learn which of the genes in our database switched on at the end of the ripening process - the time when flavour comes into fruit."

When the researchers identified the genes responsible for flavour production, they tested whether they continued to produce the same compounds when inserted into bacteria or model plants.

Finding that they caused the same effect in other organisms, the scientists proposed that the genes could be used to generate large amounts of the flavour compounds for harvest by industrial means.

"Using starter compounds already in bacteria, you can then use enzymes to reproduce these during fermentation.

The compounds end up floating into the airspace above the bacteria, where it can be harvested," explained Dr Newcomb.

When the flavour compounds are harvested, they are guaranteed to be 'nature-identical' - with the same molecular make-up - as those found in fruit because they are produced by the same gene, he added.

There are clear advantages for flavour houses from using such a technique over chemical synthesis to mimic natural flavours and fragrances found in fruit and vegetables, particularly at a time when consumers are increasingly demanding that food ingredients are natural.

"Chemical synthesis requires heat and pressure, so is reliant on increasingly expensive and polluting fossil fuels for energy.

What's more, chemical synthesis can never truly recreate nature; the flavour or fragrance will typically be slightly different to that found naturally in fruits and flowers," he said.

And extraction of compounds from fruits, while resulting in a 'natural' flavour, is expensive and produces only limited quantities of product, he added.

Biofermentation techniques, on the other hand, can produce large amounts of a desired compound at a low cost and with little environmental impact.

While the possibility of 'fermenting' genes to produce compounds has been well understood for many years, science has generally lagged behind in identifying which genes are needed to produce the desired outcome.

But new techniques that help determine which genes create each compound, and how those compounds combine to create a flavour or fragrance, has allowed the HortResearch scientists to gain a groundbreaking insight into flavour production in nature.

To test its concept, the company has recreated a fruit compound called alpha-farnesene, responsible for the distinctive aroma of green apples.

It has filed international patent applications on the use of the applicable gene in creating the fragrance, and is in talks with flavour houses to license the technology.

Bringing the flavour, and others resulting from the genetic research, to market will depend upon how much it currently costs to produce the same flavour through extraction, suggests Dr Newcomb, although extraction tends to be more expensive.

However with consumers paying more for 'natural' foods, the market looks ripe for novel, natural flavours.

Dr Newcomb will present details of the research at the World Congress on Industrial Biotechnology taking place in Toronto, Canada this week.