Do frozen products keep good nutritional qualities

Contrary to popular belief, frozen vegetables and fish are sometimes richer from a nutritional point of view than fresh produce, which has lagged a bit behind.

Do frozen products keep good nutritional qualities
frozen food

Subway, work, "freezer": many families cannot imagine their life without frozen food. Daily life does not always allow time to peel fresh vegetables or cook fish in the oven. A study published in 2009, however, called into question the nutritional virtues of this method of conservation so practical. 

Indeed, according to an article published by Spanish researchers in 2009 in the journal Food Research International, a single day of freezing is enough to cause broccoli to lose 15% of its antioxidant properties. A leakage of 23% for green beans and 26% for peas.

Folate, vitamin C, and polyphenol kept intact

"The studies relating to all the antioxidant molecules are not necessarily relevant, insofar as some of them have no beneficial effect on health", comments Catherine Renard, director of the Safety and Health Unit. quality of products of plant origin at the National Institute of Agronomic Research (INRA). "On the other hand, when it comes to folate, vitamin C, and polyphenols that we need in our diet, the studies we have carried out show that their levels remain stable in frozen vegetables, once the blanching stage has been passed. . "

Blanching is a heat treatment that involves heating vegetables to 90-95 ° C for a few minutes to deactivate degrading enzymes. In fact, "only carotenoids [which include beta-carotene, which is also called provitamin A, and lycopene, which has proven effects against prostate cancer, Editor's note] sometimes support storage less well once frozen: it There is then a loss of 30% over one year for certain products, ”explains Catherine Renard.

The nutritional quality of certain vegetables preserved

On the other hand, for certain vegetables such as spinach, underlines the researcher, freezing after picking guarantees better levels of vitamins and nutrients than storage in the open air. Be careful not to thaw vegetables before cooking them, because defrosting destroys some of the vitamins. "A frozen vegetable can contain more vitamins than a" fresh "vegetable that has been lying around for days on a stall and then in the kitchen", adds Dr. Jacques Fricker, nutritionist at the Bichat Hospital in Paris.

When it comes to fish, their proteins, minerals, and carbohydrates are resistant to freezing. But some lipids, including the famous omega-3s, are destroyed more quickly in frozen products. “A fish caught six months ago contains almost no omega-3s. Unless it is whole, or if it has retained its skin, ”explains Jacques Fricker. The solution is to buy a whole fresh fish from the fishmonger and freeze it yourself. Or turn to canned goods. "Canned sardines and mackerel often look bad because they're cheap, but they're high in vitamin D and omega-3s."

Frozen products should not be banned from our diet any more than canned foods. The right approach is above all to prefer unprocessed products to ready-made meals, too high in added sugar and salt, whether frozen or vacuum-packed.

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