New scientific studies show antioxidant levels in frozen produce can be higher than in fresh

Two independent new scientific studies on compounds in fresh and frozen fruits and vegetables have indicated that frozen may have higher levels of some antioxidants than their fresh counterparts.

Investigating the content of the most commonly bought supermarket fruit and vegetables, evidence from over forty tests conducted within two studies established that in 66 per cent of cases, frozen fruit and vegetables had higher nutritional levels of antioxidant-type compounds – including Vitamin C, polyphenols, anthocyanins, lutein and carotene – on day three of storage.

On this basis, researchers recommended frozen fruit and vegetables as effective in providing antioxidants needed to maintain a healthy diet. Over the last two decades it has widely been reported that antioxidants in diet can help to keep the immune system healthy by cancelling out the cell-damaging effects of free radicals.

In two separate studies, conducted by the University of Chester and Leatherhead Food Research, scientific researchers:

• Purchased fresh and frozen fruit and vegetable samples from each of the four main UK supermarket chains
• Stored each product for half a week – as might be the situation for a consumer who conducts a bi-weekly shop [source: IGD ShopperVista]
• Prepared composite samples from each produce type for analysis
• Analysed each sample for antioxidant-type compounds – Vitamin C, polyphenols, anthocyanins, lutein and carotene
• Evaluated the results of the analysis to establish the differences between fresh and frozen.

Professor Graham Bonwick of the University of Chester’s Environmental Quality and Food Safety Research Unit, who led one of the studies, said: “Our data concluded that the concentrations of antioxidant compounds measured in frozen resembled those observed in corresponding fresh produce prior to refrigerated storage. However, unlike frozen, some fresh produce concentrations exhibited a decrease during refrigerated storage to levels below those observed in the corresponding frozen produce. The effects were most noticeable in soft fruits.”

At Leatherhead Food Research, author of the second study Dr. Rachel Burch, said: “These results demonstrate that frozen can be nutritionally comparable to ‘fresh’ produce. We must disregard the mistaken opinion that ‘fresh’ food is always better for us than frozen food.”

Brian Young, Director-General of the British Frozen Food Federation said: “Fast and highly organised methods of ‘harvest-to-freeze’ have evolved with the express purpose of minimising nutrient losses. In contrast, ‘fresh’ food has been shown to spend up to a month in the chain of producers, wholesalers and retailers before consumers have access to store and prepare them. During this time we know that product deterioration takes place – to the extent that they can have lower nutritional value than their frozen equivalent.”

Both reports were commissioned by the British Frozen Food Federation. Downloadable copies of the reports and further educational information on frozen foods for the foodservice industry can be found on BFFF’s website.