All of us are concerned with getting the most out of our food, whether it is taste, quality, texture, and overall nutrition. The most nutrient dense foods are those eaten immediately after picked or caught, however not all of us are farmers, hunters, and/or fishermen. With modern technology, most of our food supply is processed for the benefits of consumer safety and food variety.
Research shows that canned and frozen ingredients are comparable in nutrition to cooked fresh counterparts. The moment you pick a fruit or vegetable, or catch a fish, or milk a cow, food starts to change texture, taste, perhaps color, and nutrient content. That’s why food producers usually process food as fast as possible, while nutrient content and overall quality are at their peak. Immediate processing helps lock these qualities into food. As long as processed foods are handled properly, from the food manufacturer to the supermarket to your home, there’s little nutrient loss. Freezing, drying, and canning retain the nutritional quality of foods. Whether food is fresh or processed, it is up to you to minimize nutrient loss in your kitchen.
Nearly every food preparation process reduces the amount of nutrients in food. In particular, processes that expose foods to high levels of heat, light, and/or oxygen cause the greatest nutrient loss. Nutrients can also be “washed out” of foods by fluids that are introduced during a cooking process. For example, boiling a potato can cause much of the potato’s B and C vitamins to migrate to the boiling water. You’ll still benefit from those nutrients if you consume the liquid (i.e. if the potato and water are being turned into potato soup), but not if you throw away the liquid. Similar losses also occur when you broil, roast, or fry in oil, and then drain off the drippings.
Freezing, when properly done, is the method of food preservation which may potentially preserve the greatest quantity of nutrients. Most frozen fruits maintain high quality for 8 to 12 months. Unsweetened fruits lose quality faster than those packed in sugar or sugar syrups. Most vegetables will maintain high quality for 12 to 18 months at 0° F or lower. Longer storage of fruits and vegetables than those recommended above will not make the food unfit for use, but will decrease its quality.
You must use good quality freezer containers to maintain the quality of frozen fruits and vegetables. A high quality container should be both moisture and vapor proof so that moisture can be kept in the product and air kept away from it. There are two types of packaging materials for home use: rigid containers and flexible bags or wrappings.
Rigid containers made of plastic are suitable for all packs and are especially good for liquid packs. They are often reusable and make the stacking of foods in the freezer easier. Cardboard cartons for cottage cheese, ice cream and milk are not sufficiently moisture-vapor resistant to be suitable for long-term freezer storage. Covers for rigid containers should fit tightly. Flexible freezer bags and moisture-vapor resistant wrapping materials such as plastic freezer wrap, freezer paper and heavy-weight aluminum foil are suitable for dry packed products with little or no liquid. Regardless of the type of storage container, press to remove as much air as possible before closing.
For more information on food storage and preservation, please visit: http://www.nutrition.gov/nal_display/index.php?info_center=11&tax_level=2&tax_subject=391&topic_id=1759&placement_default=0
Answer submitted by Mia Handell, registered and licensed dietitian at Provena Mercy Medical Center.