Two independent scientific studies conducted by the University of Chester, United Kingdom, and Leatherhead Food Research, London, on compounds in fresh and frozen fruits and vegetables indicate that frozen may have higher antioxidant levels than their fresh counterparts.
Investigating the content of the most commonly bought supermarket fruit and vegetables, evidence from more than 40 tests conducted within two studies established that in 66% of cases, frozen fruit and vegetables had higher nutritional levels of antioxidant-type compounds, such as vitamin C, polyphenols, anthocyanins, lutein and b 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.
In both studies, 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 grocery shops bi-weekly.
• Prepared composite samples from each produce type for analysis.
• Analyzed each sample for antioxidant-type compounds—vitamin C, polyphenols, anthocyanins, lutein and b carotene.
• Evaluated the results of the analysis to establish the differences between fresh and frozen.
"Our data concluded that the concentrations of antioxidant compounds measured in frozen resembled those observed in corresponding fresh produce prior to refrigerated storage,” says Graham Bonwick, professor of the University of Chester's environmental quality and food safety research unit, and leader of one of the studies. “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."
"These results demonstrate that frozen can be nutritionally comparable to 'fresh' produce,” says Dr. Rachel Burch from Leatherhead Food Research, and author of the second study. “We must disregard the mistaken opinion that 'fresh' food is always better for us than frozen food."
Both reports were commissioned by the British Frozen Food Federation.