Is fresh food really more nutritious than frozen food?
Over 30 per cent of Britons believe frozen food is inferior to fresh, and over 40 per cent say nothing would induce them to buy more of it, according to one study. Is it time to reconsider the ‘fresh is best’ mantra?
Sue Quinn investigates.
Frozen food has long had an image problem. Many home cooks sniff at freezer fare, dismissing it as poor quality, less nutritious than fresh, and somehow not good enough if you proudly prepare meals from scratch. But according to nutrition scientists it’s time for this frosty attitude to thaw.
The experts are not, of course, referring to the ever-expanding range of pre-prepared food vying for space in the freezer aisle, from bangers and burgers to pizzas and chips. But when it comes to frozen produce such as fruit, vegetables, meat and fish, scientists say these foods can be just as nutritious – more so, even – than fresh.
These days, food often has a long journey from field to fork. Apples, for example, can appear on the shelf a full 12 months after being picked, and some of the nutrients degrade during that time. State-of-the-art freezing and food transport methods allow produce to be snap-frozen moments after harvest. The more quickly this happens, the more the nutrients are preserved and the less the flavour and texture deteriorate.
Give (frozen) peas a chance
Water-soluble nutrients such as vitamin C and some B vitamins are particularly sensitive to heat, light and oxygen, and are therefore susceptible to damage, explains Ayela Spiro, senior nutrition scientist with the British Nutrition Foundation. “Freshly picked vegetables consistently show the greatest amount of vitamin C, but it begins to degrade after harvest,” she says. Rapid-freeze techniques such as blast-freezing halt the deterioration and preserve most of the nutrients. Fresh fruit and vegetables, however, can spend weeks or even months in transit; refrigerated lorries and chiller cabinets slow down the spoiling of produce rather than preventing it.
“The public tends to think that frozen products are inferior, due in part to poorly advertised items by retailers, but the scientific evidence shows otherwise,” says Dr Cath Bircher, senior researcher at Chester University’s Institute of Food Science and Innovation. A good example is frozen peas. “They’re frozen within two hours of harvest and retain nearly all the vitamin C content,” she says.
A 2013 study carried out by Chester University for the British Frozen Food Federation found that frozen blueberries actually contained higher concentrations of vitamin C than fresh. What’s more, there was a “significant” fall in the vitamin C content after the fresh berries were stored in the fridge for a few days. “It’s a fallacy to believe that frozen products are inferior,” Dr Bircher says.
What about meat and fish?
Meat and fish are more complex than fruit and veg but, if freezing is done quickly, the results can still be good, says Dr Bircher. That’s why the quality of frozen fish fillets is often good: much of it is snap-frozen at sea or soon after being caught, which locks in the nutrients in the same way it does for fruit and veg. Look out for ‘frozen at sea’ or similar on packaging when you buy.
Brett Sutton, an arbitrator at the annual Great Taste Awards and chef-proprietor of the award-winning White Post Inn in Somerset, is a fan of frozen fish. He buys fresh fish from a reliable local day-boat fisherman, then blast-freezes it.
“I reckon this fish is fresher than that from many of our local fish suppliers, who predominantly buy from boats on which the fish can be caught and packed on ice for up to 10 days before it reaches market,” Sutton says. “It then takes two days from landing to reach me. I know which fish I would rather use.”
As for shellfish (scallops, mussels, oysters, squid, prawns, crab and the like), theoretically it can be frozen for up to three months, as long as the temperature is below -18°C. Often the results aren’t great, though. Shellfish is delicate, and freezing can alter its texture and flavour, so fresh is normally best here. The exception is squid or octopus, as freezing them before cooking can tenderise the flesh.
The problem for consumers is that freezing fresh meat or fish in a domestic freezer isn’t as effective as industrial freezing. That’s because industrial freezers can freeze food within minutes but a home freezer does the job slowly, causing large ice crystals to form within the food’s cell structure. These crystals can cause cell damage, making the texture of meat and fish stringy and chewy when defrosted and cooked.
If you like the convenience of keeping a stash of meat and fish in the freezer, buy it ready frozen. “I’d never buy premium meat products, then freeze them – I’d always buy fresh,” says Dr Bircher.
What’s the bottom line?
Snobbery about frozen fruit, vegetables, meat and fish is misplaced. The quality of fresh produce deteriorates more significantly than many people realise, and much frozen food is just as nutritious as fresh. “Because of the degradation that occurs with the handling and storage of fresh produce, a frozen product may be nutritionally similar to something fresh a consumer has just bought and taken home,” says Ayela Spiro. And some frozen fruit and veg are actually more nutritious than fresh. Unless, of course, you’re lucky enough to be eating something just picked from a tree in the garden…