What’s more nutritious: fresh or frozen? If you think that’s a no-brainer, you might be surprised. 

When University of Hawaii nutritionist Joannie Dobbs lived "another life" in 1985 as an environmental biologist, she worked in a field of green beans in California. Dobbs would see giant trucks for some of the nation’s biggest frozen-vegetable companies pull up. These were mobile factories. As pickers harvested the beans, they would place them in a machine on the truck, and a short time later the beans would come out flash-frozen and packaged. Another refrigerated truck was waiting to take the frozen beans to a plant to be boxed. 

Total time elapsed was about an hour. Such efficiency is significant, says Dobbs, because enzymes begin degrading produce the moment it’s picked. Freezing slows down that process considerably.

"We think fresh has so much more vitamins than frozen, but when fruits and vegetables travel from the mainland or Chile, they’re shipped over a two-week period, and the vitamins are breaking down the whole time. By the time something is browning, nutrients are already decreasing," she said. 

"So frozen has the potential to have as much or more vitamins than fresh."

Preparing your own fresh vegetables and freezing them can also streamline the cooking process, saving time and labor as well as reducing waste.

Dobbs says one of her favorite vegetable combinations is mushrooms and onions, so she stir-fries them fresh in large batches and then freezes them in small portions. 

"When they’re thawed, they taste like they’ve just been sauteed. I add them into other things I’m cooking," Dobbs said. 

"Cooking ahead and freezing can cut down so much time in cooking. Cleanup is decreased so drastically because there are fewer pots and pans to wash. And it cuts down on visits to the store because I just take what I need out of the freezer."

Once, Dobbs was given 10 pounds of romaine lettuce. After maxing out on fresh salads, she found that romaine leaves are hardy enough to use in place of pasta when making lasagna. 

"They froze amazingly well," she said. 

Here are other tips on freezing food from Dobbs, the National Center for Home Food Preservation and the North Dakota State University Extension Service. 

FREEZING FRUIT

The browning, or oxidation, of produce means that vitamins are being depleted (though minerals are intact). When freezing fruit, a dose of ascorbic acid helps hinder that process. While freezing guides recommend dipping fruits in ascorbic acid liquid, Dobbs simply dissolves a vitamin C tablet — a form of ascorbic acid — in water in a spray bottle, then sprays her fruit with a quick coating. 

She says that if the fruit will be used within one to three months, spraying is not necessary. 

Packaging food 

>> Food must be frozen in bags or rigid containers that are moisture-vapor resistant, leakproof, crack-resistant at low temperatures, easy to seal and easy to mark. When using freezer bags, remove as much air as possible before sealing. 

When using containers, leave appropriate "head space" (space between food and closure) in case food expands when frozen. 

A guide: For liquids in a wide-top container, leave a half-inch for a pint, 1 inch for a quart and a half-inch for dry food. In narrow-top container storing liquid, leave 11/2 inches for pint and quart sizes, and a half-inch for dry food.

Label each package with kind of food, added ingredients, packaging date, serving amounts and form of food (whole, sliced, etc.).

>> Tray-freezing keeps individual pieces from being frozen together. Place food such as berries, sliced carrots and dumplings in a single layer on a tray and place in freezer. When solid, transfer to freezer bag or container. This allows for easy retrieval later. 

>> Casserole wrap: Line a baking dish with heavy-duty foil. Be sure to leave a 

11/2-inch foil collar around the edges. Place raw or cooked dishes into the pan and cover with a sheet of foil the size of the dish and foil collar. Press air out from the center and fold edges, sealing tightly. Freeze. When frozen, lift frozen food out of dish, label and return to freezer.

THAWING

Meat, fish and poultry can be cooked from a frozen state without thawing. If thawing, this is best done in the refrigerator. Or place in waterproof wrapping and under cool running water, or thaw using a microwave oven. Do not thaw at room temperature.

Dairy products should be thawed in the refrigerator.