Commentary: Frozen and tinned foods can be just as nutritious as fresh produce – here’s how

Carrots, for example, lose very little vitamin C during freezing. But they can lose a significant proportion of their vitamin C during canning because it’s a water-soluble vitamin, meaning that it’s easily broken down in water, especially after being degraded by heat.

In contrast, vitamin A loss is much lower during canning since it’s more stable against heat. In fact, more vitamin A is lost during the freezing process.

GETTING NUTRITIONAL BENEFITS WITHOUT BREAKING THE BANK

Though some nutrients can be lost during the blanching, freezing and canning processes, in many cases the foods still retain more important nutrients than they would if picked just before peak ripeness and shipped to their destination supermarket. For example, research shows that the vitamin content of frozen blueberries is comparable – and sometimes even higher – than that of fresh blueberries.

And while tinned peaches may lose some nutrients during the canning process, there’s then virtually no change in their nutrient levels even after three months in storage. The same is true of many other canned and frozen produce, such as peas, sweetcorn and broccoli, which keep many of their nutrients even after a year in storage.

The same applies to other compounds present in foods. For example, polyphenols – natural compounds found in most fruits and vegetables, some of which have been linked to better heart health – can be preserved for longer through freezing.