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Frozen, fresh or canned food: What’s more nutritious?

来源:BBC 作者: 时间:2020-04-28 Tag: 点击:

Tinned and frozen fruits and vegetables tend to be seen as less nutritious than fresh versions. But that's not always the case.

Once picked, that fruit or veg is still using its own nutrients, breaking them down in order to keep its cells alive. And some nutrients are particularly vulnerable. Vitamin C, which helps the human body absorb iron, helps reduce cholesterol levels and protects against free radicals, is also especially sensitive to oxygen and light.

Refrigerating produce slows down the process of nutrition degradation, although the rate at which nutritional value is lost varies from one product to the next.

In 2007, Diane Barrett, a former food science and technology researcher at the University of California, Davis, reviewed numerous studies looking into the nutritional content of fresh, frozen and tinned fruits and vegetables. She found that spinach, for example, loses 100% of its vitamin C content in seven days if stored at a room temperature of 20C (68F); it loses 75% if refrigerated. But carrots, by contrast, only lose 27% of their vitamin C content when stored for a week at room temperature.


Carrots lose 27% of their vitamin C when stored at room temperature – but that’s much better than other kinds of produce (Credit: Getty Images)


The food industry has developed ways to freeze produce almost immediately after it’s harvested (Credit: Getty Images)


Canned foods can have added salt and sugar (Credit: Getty Images)


What’s most important is to eat a variety of foods – which usually requires fresh, frozen and canned (Credit: Getty Images)


Some research shows that organic produce retains more nutrients (Credit: Getty Images)

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