Freeze-drying fruit is top technique for retaining nutrients: Study

By Louis Gore-Langton

- Last updated on GMT

©iStock
©iStock
Freeze-drying fruit retains almost all of its nutritional value and can help keep ingredient lists clean, according to a study funded by ingredient supplier Chaucer.

The study was jointly conducted  by Newcastle University’s School of Agriculture, Food and Rural Development and global ingredient producer Chaucer. 

The freeze-drying process (also known as lyophilisation) works by freezing a product before reducing the surrounding pressure. This forces  frozen water inside the product to sublimate directly into gas. 

A recent investigation on British television channel Channel Four’s Food Unwrapped questioned the authenticity of freeze dried fruits in breakfast cereals and found the fruit was indeed real but offered no insight into nutritional value or the freeze-drying process.

The new joint study at Newcastle University ran over one year and measured the nutritional value of freeze-dried strawberries against those of standard frozen ones. It reported no ‘significant’ differences in vitamin C or anthocyanin content – powerful antioxidants with various health benefits.

Andy Ducker, CEO, at Chaucer Food Group said the freeze-dry process also increases shelf-life, reduces waste produce, facilitates global transportation, and requires no preservatives, additives or sugar – meaning producers can keep ingredient lists clean.

Previous research conducted by Sheffield Hallam University found that freeze-drying strawberries resulted in zero loss of vitamin C and phenolic content and minimal losses in total antioxidant capacity (TAC) – only 8%. In contrast, fresh strawberries chilled for equal time showed a vitamin C loss of 18%, a TAC loss of 23% and a massive 82% loss in phenolic content.  

Besides fruit for breakfast cereals, freeze drying  can also be used for teas and coffees, ready meals and chocolate. In the US, freeze-dried ice cream is a popular snack and is marketed as ‘space food’ due to its use by astronauts.

Shadbolt told FoodNavigator they are currently experimenting with use of freeze-dried goods in functional foods.  

Chaucer distributes goods to global ‘blue chip’  companies such as Kelloggs, Nestlé, Starbucks, Unilever, and General Mills.

Flash-Freezing

Okobay, a British based producer of vegan snacks has recently launched a range of ice-cream alternative products in Sweden. 'Pop Fruits' are fruit sticks 'flash-frozen' directly upon harvest, as a way of preserving the nutrients. Boasting gluten-free, non-GMO and additive/- and preservative-free content, the sweets are 100% fruit - currently either pineapple or mango.

Okobay plans to expand Pop Fruits elsewhere in Europe. The flash freezing technique is a  good way of conserving nutrients and appealing to the health and wellness market, it says.

Related topics: Science

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