Research offers chance to naturally breed healthier fruits.
Auckland, New Zealand, 26 August 2007 – Researchers at New Zealand fruit science company HortResearch have discovered the missing link in our understanding of how plants produce Vitamin C. The discovery completes a scientific quest begun in the 1930’s and opens new opportunities for plant breeders to grow new fruit varieties with higher levels of this crucial vitamin.
Somewhere along our evolutionary pathway humans lost the ability to produce Vitamin C. We’ve been slaves to plants ever since. Without the Vitamin C we get from eating fruit and vegetables, humans could not survive. If deprived of this essential acid our bodies cannot perform crucial metabolic functions that help rebuild body tissues and fight infection and disease.
Severe Vitamin C deficiency causes a condition early sailors called scurvy. Far from land for months at a time, sea-farers could not maintain the required intake of fruit, so until the voyages of Captain Cook during the late eighteenth century, illness and often death from scurvy was part of a sailor’s lot. En-route to discovering New Zealand, Cook solved the problem by forcing his crew to drink lime juice or eat sauerkraut. They didn’t like it much, but they lived to thank him for it.
Things aren’t much different today; if we don’t eat enough fruit we often boost our Vitamin C from a concentrated source – but instead of limes, we turn to capsules and pills filled with man-made Vitamin C. The vitamin was first identified in the1930’s and wholesale manufacturing soon followed, but it has taken another 75 years to finally learn how plants have been naturally creating Vitamin C for millions of years.
The breakthrough came from a HortResearch team studying kiwifruit, a plant naturally high in Vitamin C (typical green kiwifruit have around 100mg per 100g of fruit.) Working with an inedible wild kiwifruit variety called Actinidia eriantha – which contains a massive 800mg of Vitamin C per 100g - the team isolated the last undiscovered enzyme in the pathway to Vitamin C biosythesis and proved the enzyme controlled Vitamin C in plants.
A paper outlining the HortResearch discovery was recently published in the Proceedings of the National Academy of Science of the United States of America. Dr Bulley will personally present the information to local and international scientists who gather in Queenstown, New Zealand this week for the 17th annual Queenstown Molecular Biology meeting.
For many scientists, this marks the end of the Vitamin C story, but for HortResearch, it’s just the beginning. We’re now using this new knowledge to plan the next generation of fruit cultivars that could provide consumers with high levels of natural Vitamin C.
"That’s because even after millions of years of practice, most plants aren’t actually much good at producing Vitamin C – or more precisely, they’re selfish, producing only as much as they need for themselves," says Dr Sean Bulley, one of the scientists responsible for HortResearch’s breakthrough Vitamin C research.
"Many traditional fruit such as apples or bananas provide less than half the recommended US daily intake of 90mg/day for an adult male. Even an orange can’t quite measure up."
Other non-governmental agencies propose much higher intakes of vitamin C than that recommended by the US government, so there is clearly a problem. Or is there? After all, there are plenty of Vitamin C supplements on the market. The trouble is, when taken in the high doses provided by some tablets and capsules, Vitamin C can overwhelm our kidneys, which go into overdrive to flush it from our system.
"So, while the Vitamin C in a pill is quickly absorbed by our bodies, often a lot of it is just as quickly excreted," says Dr Bulley.
"However, there is a suggestion that when consumed through fruit, Vitamin C is absorbed much more slowly, so you get the full benefit as well as all the other healthy properties of fruit such as fibre."
Dr Bulley and other scientists in his team are now working with HortResearch’s fruit molecular biologists to identify molecular markers that will enable them to quickly recognise high levels of Vitamin C biosynthesis – the first step in ultimately breeding new fruit that contain much more Vitamin C than those available today.
These markers can then be used by breeders to identify plants within fruit breeding programmes that promise high levels of Vitamin C production. These plants can then be more closely studied and used in breeding new varieties that offer consumers a natural, convenient and healthy opportunity to increase their Vitamin C intake while also enjoying all the added benefits of eating whole fruit.
HortResearch’s Science General Manager, Dr Bruce Campbell, says a high Vitamin C apple would be an excellent candidate for further research, although the science could be applied to almost any fruit.
"Obviously kiwifruit already have very high levels of Vitamin C, so there is little need for this science in that crop. Instead we will be looking at other fruits that are commonly consumed around the world and which could use a Vitamin C boost."
About HortResearch
HortResearch is a New Zealand-based science company, acknowledged as a world leader in integrated fruit research using unique resources in fruit, plants and sustainable production systems to provide novel technologies, innovative fruit and food products with high consumer appeal.
Home to the world’s largest fruit compound database, as well as leading-edge scientific capability in plant breeding, tree, vine and fruit physiology, HortResearch has earned considerable acclaim as the name behind development of ENZA JAZZ™ brand apples and a range of other successful cultivars including blueberries, peaches and pears.
The company also enjoys further praise as the research team behind the development of the world''s first intelligent fruit labelling system, ripeSense™ marketed by RIPESENSE Limited.
HortResearch is now broadening its commercial science capability, utilising knowledge in phytochemicals, food chemistry, sensory, biochemistry, and plant molecular biology to find new ways to improve human health, wellbeing and performance.
The company is also developing breakthrough science and technology to meet emerging markets for functional foods and naturally produced flavours and fragrances.
Media Contact:
Roger Bourne
Senior Communications Advisor
HortResearch
Private Bag 92 169
Mt Albert, Auckland
New Zealand
Ph +64 9 815 4200 ext 7057
Mob +64 27 207 1712