Blueberry growers upbeat despite frost

By PHILIPPA STEVENSON agricultural editor

The blueberry industry is confident of recovering from a disastrous frost, which will cost some growers up to 60 per cent of their production.

A severe late frost on October 25 destroyed much of the crop in the Waikato, which grows 90 per cent of the country's blueberries.

Alison Furniss, a director of New Zealand's biggest grower, Blueberry Country, said the losses were likely to mean a shortage of fresh fruit on the domestic market and the scrapping of a planned promotion.

Waikato grower Diane Beach said growers were concerned whether they could maintain export volumes into the main market of Japan, where a shortfall could cost long-term market share.

But the worries were put aside at a seminar for growers on Friday at Ruakura research centre, where HortResearch conducts blueberry plant breeding experiments.

Growers were upbeat about more international research, to which HortResearch scientists contribute, showing blueberries' health-giving properties, particularly antioxidant activity.

In the bloodstream, antioxidants absorb oxygen free radicals, which scientists believe are behind such ailments as heart disease, cancer, arthritis, skin wrinkles, and impaired vision and memory.

Leading blueberry researcher Dr Wilhelmina Kalt, of Agriculture and Agri-Food Canada, said the blueberry family, particularly wild-growing European bilberries, had a long history in pharmaceutical products.

A search found at least 180 products on the market containing bilberry extracts, many of them recommended for eyesight and circulation.

"So it is well worth looking at the other blueberry species," she said.

One just-completed study by her group found that rats fed a diet high in blueberries had less nerve damage after a stroke than a control group, suggesting the antioxidant and anti-inflammatory properties of blueberries played a protective role.

The study also showed that blueberries appeared to regulate blood sugar levels.

The compounds being studied come under the antioxidant umbrella but are divided into many groups.

One large group is called phenolics, under which another sub-group called anthocyanans are prevalent in blueberries and give the fruit its deep colour.

"These are the compounds you are targeting in your [plant] breeding programme because to increase the level of anthocyanans enhances the whole functionality of your New Zealand cultivars," Dr Kalt said.

Researchers were working to isolate which compounds caused the effects seen in the studies and also what impact production and processing had on the level of antioxidants in the fruit.

Heat and exposure to oxygen, or oxidation, damaged the fruit but freezing had little effect.

Wild blueberries, which make up about half the large North American blueberry production, were shown to have the highest levels of the health-giving compounds.

In New Zealand, where the entire crop is cultivated, the leader of HortResearch's breeding programme, Narandra Patel, said researchers were examining ways to breed cultivars with more of the properties of the wild berries.

"People shouldn't care whether they eat cultivated or wild blueberries," said Dr Kalt, who blends the fruit into a "smoothie" drink each morning.

"Compared to other fruits and vegetables, blueberries are head and shoulders ahead."

Dr Kalt's visit to New Zealand is the second by a high-profile blueberry researcher in a year.

Last December, American neuroscientist Dr Jim Joseph, of the Human Nutrition Research Centre on Ageing at Tufts University, Boston, was in the country.

His groundbreaking research in 1998 showed that eating blueberries not only halted some effects of ageing but reversed them.

It caused a run on supermarket blueberry stocks.