Studies into benefits of gold kiwifruit

Despite the question hanging over the future of gold kiwifruit after the Psa outbreak, new research is being done to establish the health benefits specific to the gold fruit.

Kiwifruit marketer Zespri, which owns the patent for the gold fruit, commissioned the research by crown research institute IRL. Initial studies show little difference between the types and levels of complex carbohyrates in the green and gold varieties, but IRL chemist Simon Hinkley said the gold fruit had higher amounts of a compound known to break down more easily in the stomach.

He said a number of studies had shown kiwifruit to be beneficial for the digestive system because they were high in fibre and contained bioactive agents, such as polysaccharides or complex carbohydrates, promoting the growth of beneficial intestinal bacteria.

But Hinkley said most research published to date has focused on the original, green variety, with a gap in knowledge about the newer gold kiwifruit.

While results so far had not revealed significant differences, Zespri health science manager Lynley Drummond said the research provided the tools needed to study the different health benefits of green and gold kiwifruit.

"Now we know the structure of the components in each variety, we can follow them through the digestive process."

The research is being carried out through a collaborative project involving IRL, Plant and Food Research, AgResearch and the Riddet Institute.

"We've been able to track the fate of fibre from both green and gold kiwifruit as it passes through the digestive system, helping us understand how and why kiwifruit are good for people.

"It's no longer good enough to say a product must be good for you - consumers are rightly demanding robust science that proves the efficacy of foods that make claims about their health benefits."

The original, analytical work by IRL's carbohydrate chemistry team has been published in Carbohydrate Polymers, a peer-reviewed journal focusing on carbohydrate polymers with industrial uses.

Drummond said the findings from the follow-up research, would be published in the near future.

It was the glamour fruit of the industry, famed for its golden flesh, sweet taste, health attributes and the returns it brought to growers, but now, around 20 years since it was released, the kiwifruit known as Hort16A or Zespri is under threat.

Earlier this month, Kiwifruit Vine Health reportedly stated: "Gold 16A almost definitely does not have a future in the Psa-V environment and this cultivar will need to be eventually replaced."

The organisation is charged with helping the industry overcome the vine killing disease, to which the gold variety is particularly susceptible.

Zespri Gold was bred naturally in the late 1970s using seeds imported from China and crossing a female, yellow-fruit-producing plant with a male plant know to produce large, succulent fruit. It is particularly popular in Asia due to being sweeter than the green variety.

- additional reporting APNZ