The producers of the specialty Queen Garnet plum - now in season - say new research shows the plum's high antioxidant content may provide relief for the one in 250 Australians living with Inflammatory Bowel Disease (IBD).

Queensland-based Nutrafruit, which holds the global licence to market the Queen Garnet, has invested heavily in research on the back of a lengthy list of health benefits discovered since the plum's commercial launch in 2014, with more studies underway.

Nutrafruit chief executive officer Luke Couch said latest research from the University of Southern Queensland (USQ) conducted on the nectar of Queen Garnet plums found consumption of anthocyanins - powerful antioxidants - significantly reduced the effects of IBD in rats.

"USQ researchers attribute this to the known anti-inflammatory responses of the plum's properties which are also known to reverse inflammation of the heart and liver, blood pressure and fat levels in obese and hypertensive rats," Mr Couch said.

"Crohn's & Colitis Australia predicts the prevalence of IBD will increase by 25 per cent to 100,000 by 2022. The new research shows there may be dietary ways in which people can reduce inflammation of the bowel and symptoms of this debilitating condition."

Prized for having up to seven times the antioxidants found in other commercial plum varieties and up to six times the antioxidant content of blueberries, the Queen Garnet makes a fleeting appearance on Australian supermarket shelves between February and March. It continues to increase its following among health-conscious consumers.

"On average, two Queen Garnet plums a day provide an anthocyanin content that research has shown results in health benefits. They also have a high fibre content due to their natural density," Nutrafruit food scientist and nutritionist, Hannah Naismith said.

The power of purple

Queensland's Department of Agriculture and Fisheries originally bred the Queen Garnet in its quest to develop a disease-resistant plum.

"When the breeders cut it open and saw its purple flesh, they knew they'd found something special because deep purple flesh is indicative of a high antioxidant content," Mr Couch said.

"The original intention was to process a range of value-added health products so people could reap the benefits year 'round. However, it quickly became apparent, there was also a strong market for the fresh product.

"Now, health-conscious consumers can enjoy the benefits of the Queen Garnet either fresh, seasonally, or any time of the year with its value-added line-up including a 100 per cent nectar."

In the first human trials conducted by the University of Wollongong in 2017, scientists found consumption of a single serve of 300mL Queen Garnet nectar significantly lowered blood pressure.

Further research is being undertaken by USQ, Queensland Alliance for Agriculture and Food Innovation and the University of Wollongong with findings set to be released this year.

Characteristics of the antioxidant plum

Queen Garnet plums have distinctive deep purple skin with appealing golden speckles. They have dense, deep purple flesh which is sweet and juicy.

Mid-to-large Queen Garnets are heavier than most plums due to their density and can weigh up to 200 grams each. They have a small seed-to-flesh ratio.

Mr Couch said Queen Garnet plums consistently achieved a brix or natural sugar level of 17 - considerably higher than other plums - because they were tree-ripened.

"We would rather visit a tree more often and hand-pick the fruit when fully ripe, than pick early to boost the packhouse yield," he said.

"Maintaining sweetness is paramount if we are to achieve a consistent eating experience."

Strong season predicted for a growing plum

Mr Couch said Nutrafruit expected to send nearly triple the volume of Queen Garnet plums to market this season, compared with last season. The crop is expected to reach full production by 2022.

"This will be the first season we've had a significant volume because it takes three to four years for trees to produce fruit," he said.

More than 30 growers in every Australian state except the Australian Capital Territory and the Northern Territory produce the plum under licence. Victoria's Goulburn Valley, known for its ideal stonefruit growing conditions, is the key growing region with some 40 per cent of the crop.