Saturday, December 2, 2023

Study puts NZ cherries on top for health benefits

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High pressure liquid chromatography reveals nutritional profile of NZ-grown cherries.
The study also compared fresh and packaged cherries to learn if nutrients were lost during processing.
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Cherries grown in New Zealand are officially jam-packed with components essential to human health, according to new research.

Cherries can join the ranks of blueberries and other colourful fruits grown in New Zealand with their impressive antioxidant and vitamin profile, according to work done at the Riddet Institute, at Palmerston North’s Massey University.

Riddet Institute lead scientist Dr Ali Rashidinejad said the study is the first of its kind to systematically analyse the nutritional and bioactive (phytochemical) compositions of the main cherry varieties grown in New Zealand. Earlier research has focused on cherries grown overseas.

Rashidinejad said cherries contain numerous nutrients, such as vitamins A, E, K, C and B, carotenoids, lutein, and zeaxanthin. 

Cherries have been recognised for providing significant health benefits such as decreasing markers for oxidative stress, inflammation, exercise-induced muscle soreness and loss of strength. 

They are also thought to improve blood pressure, arthritis and sleep. 

Rashidinejad said there are 17 main varieties grown in NZ. 

This study focused on six top-selling varieties grown in Cherri Global orchards in Otago: Bing, Rainier, Kordia, Lapins, Sweetheart and Staccato.

The study also compared fresh and packaged cherries to learn if nutrients were lost during processing.  

Researchers looked at proteins, carbohydrates, sugars, fats, fibre, fat-soluble vitamins and water-soluble vitamins. “Basically, in terms of nutrient profiles, we have explored everything we could. And the same with the bioactive compounds,” Rashidinejad said.

“We concluded that all six varieties were rich sources of different nutrients: minerals, vitamins, amino acids, and phenolic compounds – the antioxidants. These latter compounds, the phenolic compounds, were what most interested us because they are potent antioxidants with numerous scientifically proven health-promoting properties.”

Rashidinejad said almost 30 phenolic compounds were studied, in collaboration with Plant & Food Research, using high pressure liquid chromatography techniques. 

Most of these compounds were present in differing amounts, with vitamins A, C, E, B1, B2, B3, B6, B9 (folate), and K also detected and quantified in the fresh, packaged and frozen cherry samples. 

High concentrations of vitamin C were confirmed. 

Rashidinejad said the cherry season is quite short, with early varieties ripening in late December and all finished by early February.  

The delicate stone fruit is not easy to grow, requiring extensive bird protection, and cherries are labour intensive to pick and process.  

After picking, cherries are washed at pack houses and exported or distributed around the country, as either fresh or frozen product. The comparison between fresh and packaged fruit found processing had minor effects on the nutrients and bioactive compounds of the fruit.

“We found only some minor differences and little effect from the time and the process of washing, drying and packing,” Rashidinejad said. 

“It’s good news that the transport and packing does not have a major effect on the health-promoting compounds.”

He said future steps would be finding ways to use the waste products produced during cherry processing. 

It has been estimated that 8000t of cherry waste are produced in New Zealand every year.  

Because washing and packaging do not significantly reduce the nutrient profile of the fruit, this could lead to new uses for the waste or the seconds that don’t get to shop shelves. 

Waste from cherries could be converted into a high-value ingredient for the food industry in the future. This could be in powdered or frozen form, or as a component in another food product.

The research into NZ cherries was jointly funded by a grant from the High-Value Nutrition National Science Challenge to Cherri Health and Manufacturing (CH&M) and the Bioresource Processing Alliance with Cherri Global.  

The work was carried out by the scientists at the Riddet Institute and Plant & Food Research over the course of several months late last year.

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