Local foods are a fantastic choice year around as the produce is harvested and sent to market right away or stored in proper conditions for the winter, preventing the breakdown of nutrients and flavour. However, when preparing meals or recipes in the winter or during the ‘off season’ that require vegetables such as peas, broccoli, peppers, celery, green beans, corn, etc., should we opt for fresh, frozen or canned?
Imported, fresh vegetables in the winter can often be quite expensive. Furthermore, produce to be exported is grown for transport and stability as opposed to flavour and nutrient content. Imported vegetables are also harvested before fully ripened in order to increase the shelf life and are therefore unable to produce their full spectrum of nutrients and flavours. Finally, many vegetables are treated with ethylene gas in order to ripen them during transportation, which can produce a mealy, flavourless product. As imported products may have up to three weeks between harvest and intake, there may be as much as 50% fewer nutrients in the product as nutrients deteriorate as soon as a vegetable is harvested. Mind you, fresh vegetables are still a source of nutrients and antioxidants when consumed and are a healthy option year around.
Frozen produce, however, is convenient and can be inexpensive. Frozen vegetables are sliced and ready to go and can be added to any cooked meal from frozen. Produce that is grown for freezing is harvested, blanched (with the exception of fruit and some vegetables) and flash frozen for maximum nutrient retention. Blanching the vegetables deactivates enzymes that would otherwise breakdown nutrients and flavour after harvest. Although the vegetables lose some nutrients during the blanching process, there is minimal nutrient and flavour loss during freezer storage. Frozen vegetables should be cooked from frozen in order to retain structure or texture, flavour and nutrients.
You can also purchase local, fresh fruits and vegetables during peak season and freeze them for the winter. If taking this approach, it is best to freeze individually on a tray and then store in the freezer in a sealed container without air (or a reusable freezer bag) so the vegetables don't stick together and you can take them out portion by portion. You can also blanch the vegetables first to retain their texture.
In terms of canned foods, there is some controversy around the BPA in aluminum cans, however, purchasing no to low sodium canned goods can be an inexpensive alternative to frozen or fresh, just make sure to rinse them well before use. Although some nutrients are lost during the canning process, some canned vegetables such as tomatoes may actually be nutritionally superior to their fresh counterparts due to the release of lycopene, a powerful antioxidant, from the cell walls during the cooking/canning process.
In closing, choosing local vegetables year around is likely the best option, but there are times where imported foods can come in handy, especially throughout the winter months. All vegetables, whether fresh, canned or frozen, have a role in meeting us meet our daily vegetable needs (about 2 cups) and depending on your lifestyle and what works best for you, any of the above options will do.
Eat Well Halifax,
Nicole Marchand, RD