Written by Alex Evenson, Philabundance Nutrition Educator, with additions from Caity Rietzen, Culinary Literacy Center Supervisor
Frozen peas, canned beans, and potato chips. What do these three food items have in common?
Since the onset of COVID-19 last spring, many Americans have been trying to limit how often they go to the grocery store. At the same time, we are at home more than usual and may be surprised how quickly we run through food. Fresh produce is preferred by many but will also spoil the fastest, and generally should be eaten within the week. A key strategy to save money and shop less is to buy fruits and vegetables in their fresh, frozen, and canned forms. Once a crop is picked from the ground, the nutritional quality and taste starts to decrease over time. Since our fruits and vegetables come from all over the world (with the majority grown in California), a lot of the "fresh" produce we buy was picked several days ago.
While buying fresh produce is still a nutritious choice, frozen and canned produce have long shelf lives and can actually have more nutrients than fresh! When asked which form of fruits and vegetables is the healthiest, people often say fresh because frozen and canned are processed and have additives like salt. But when we say that a food is processed, what do we really mean?
The U.S. Department of Agriculture (USDA) defines a processed food as one that has undergone any changes to its natural state. This includes washing, cleaning, milling, cutting, chopping, heating, pasteurizing, blanching, cooking, canning, freezing, drying, dehydrating, mixing, packaging, or other procedures. Since food begins to deteriorate as soon as it’s harvested, processing is necessary to stop the growth of the many bacteria and enzymes that spoil our food.
Additionally, there are many foods whose nutritional quality is improved by processing. Canned tomatoes, for example, have more of the essential phytonutrient lycopene than fresh tomatoes. Milk is fortified with Vitamin D, which most Americans do not get enough of, and our salt has been iodized for years due to iodine deficiencies. When it comes to processed food, "...the longer the ingredients list, the more highly processed a food is. However, an ingredient that is not recognizable or has a long chemical name is not necessarily unhealthful", such as ascorbic acid which is added to prevent frozen fruit from browning.
Fruits and vegetables are frozen at the peak of their ripeness, so they supply us with the maximum benefits for our bodies. When we decrease the temperature a food is held at through freezing, it slows the growth of microbes, as well as enzymes that ripen and spoil food. Fruit is simply washed and frozen, but vegetables need to be blanched before freezing. Blanching means the vegetables are placed in boiling water, removed after a couple minutes, and then placed in ice water. This process not only kills microbes with the hot water but it also sets the chlorophyll in green vegetables so they keep their vibrant green color. It also softens and partially cooks the veggies, making it a convenient ingredient for a cook to quickly heat up later.
Canning was invented more than two hundred years ago, before we even knew that germs could infect food and make us sick. A Frenchman named Nicholas Appert invented this method after Napoleon Bonaparte offered a cash reward to whoever could come up with a way to feed French soldiers. Though the containers we use may have changed over the years, the basic method has not.
Similar to when we freeze foods, canning involves changing the temperature of food to kill microbes. In this case, the food is heated to very high temperatures first (around 250 degrees Fahrenheit) and then cooled before being placed in a sterile container. Also like the freezing process, canning facilities are located near farms so that the food can be canned immediately after harvest for the best flavor.
Drying is another way to preserve fruits and vegetables in addition to meat, beans, and wheat. Instead of changing the temperature, moisture is removed so that microbes can’t survive. Dried fruit is much sweeter since the fruit shrinks as the water is removed, making the fructose, or fruit sugar, more concentrated. This is why a serving size of fresh cherries is 1 cup whereas dried cherries is ¼ cup.
Returning to the original question: what do the frozen peas, canned beans, and potato chips have in common? They have all been processed! Potato chips are the most processed of the three and have the most added salt and fat. When choosing processed foods, specifically frozen and canned, try to look for products that are low in sodium and fat, with no added sugars. The next time you shop, make sure to compare prices and fill your cart with fruits and vegetables in all their forms.
Ready to give these other sources of vegetables a try? Check out this great recipe which uses canned carrots to make a delicious dish!
Maple Glazed Carrots
Recipe by Leigh-Ann Charles, MPH
- 1 15 oz can of carrots
- 1 TBS maple syrup
- 1 tsp high heat vegetable oil (canola, safflower, sunflower, coconut)
- 1 tsp butter (can substitute with a plant-based butter)
- Salt for taste
- Medium saucepan
- Rubber spatula or wooden spoon
- Empty carrots into strainer and rinse.
- Strain and gently pat dry to remove excess water Heat a medium saucepan on medium high heat for a few minutes.
- Using a high heat oil add oil to the heated pan.
- Add carrots to pan in a flat layer and cook for 5 minutes. Avoid stirring to prevent breaking the carrots.
- After 5 minutes, add maple syrup—gently stirring to evenly coat carrots. Cook for 2 minutes.
- After 2 minutes, add butter and remove pan from heat.
- Stir once for even coating and place in serving bowl.
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