Fresh Frozen or Canned Fruits and Vegetables, Which is More Nutritious?

fresh fruit and vegetables

fresh fruit and veggies

There is much debate over which foods are more nutritious to eat. We know that the American diet includes too few fruits and vegetables, and that all of us should consume more of these. The argument seems to be that we should eat fresh produce where possible and that frozen or canned fruits and vegetables are not as good for you as fresh food products are. But is this really true?

In an ideal world, we would all consume fruits and vegetables at their peak of maturity. This would require us to eat seasonally and locally. Unless one has access to a home-garden or a local farming coop, this really is not possible. The distance from farm to plate for much of the food grown in America is over 1,500 miles, so much of the fresh foods we eat have been picked days or even weeks in advance of being sold for consumption (CUESA, 2012). The question that needs to be answered is, how much nutritional value is lost between harvest and consumption for fresh produce, and how does this compare to frozen or canned foods which have received a certain level of processing?

Many fruits and vegetables grow only in certain regions of the country, under specific temperature and humidity, and since they are typically over 90% water, once picked, they begin a process of moisture loss and quality deterioration, along with potential microbial spoilage. Harvesting separates the product from its source of nutrients and water, and the harvested product begins to use itself as a source of nutrients. In addition, many fresh produce products have self-lives of only days before they become undesirable for consumption (Rickman, Joy C., Barrett, Diane M and Bruhn, Christine M., 2007).

 frozen vegetables

frozen vegetables

Different storage and processing technologies have been used for centuries to transform perishable produce into safe, stable, and palatable products. Freezing/refrigeration, canning, and drying all serve to transform perishable fruits and vegetables into products that can be consumed out of season and can be transported to consumers outside of a product’s growing region. Processing stops respiration, thereby arresting the consumption of nutritious components within the harvested product itself, and it also stops the loss of moisture, while eliminating the growth of micro-organisms. Though the first objective of food processing is ensuring its safety, processors also strive to produce high-quality products by processing products harvested at their peak of growth/ripeness (Rickman, Joy C., Barrett, Diane M and Bruhn, Christine M., 2007). The point here is that fresh produce will continue to lose nutrients, the longer it sits before consumption. Though some nutrients are lost in food processing, the remaining nutrients tend to be stable, once the food is processed.

One study conducted at Michigan State University examined the nutrient indices for fresh, frozen and canned alternatives for eight vegetables and ten fruit items, representing foods commonly purchased by consumers. The findings showed that the vitamin intake indices of the eight common vegetables were remarkably similar across the three options, as shown in Table 1:

Table 1

Vitamin Indices for Eight Vegetable Products

Vegetable

Fresh

Frozen

Canned

White Corn

0.013

0.011

0.014

Yellow Corn

0.013

0.012

0.014

Carrots, Whole

0.061

0.048

0.049

Spinach

0.298

0.221

0.334

Turnip Greens

0.096

0.079

0.177

Green Beans

0.049

0.035

0.039

Peas

0.023

0.027

0.030

Asparagus

0.083

0.075

0.084

Source:Miller, Steven, PhD, and Knudson,Bill, PhD, 2012, May 14.

As can be seen in Table 1, canning or freezing vegetables does not necessarily degrade their nutrient quality. In fact, in the case of corn, spinach, turnip greens, peas, and asparagus, canning seems to preserve more vitamins than freezing them or leaving them as fresh do.

The Michigan State University study also looked at fruits, as shown in Table 2:

Table 2

Vitamin Indices for Ten Fruit Products

Vegetable

Fresh

Frozen

Canned

Tomatoes

0.043

na

0.037

Peaches

0.013

0.016

0.014

Strawberries

0.041

0.030

0.009

Blue Berries

0.014

0.011

0.005

Cherries

0.703

0.520

0.247

Raspberries

0.025

0.010

0.007

Blackberries

0.031

0.023

0.010

Pineapples

0.031

na

0.017

Apricots

0.016

na

0.005

Pears

0.035

na

0.016

Source:Miller, Steven, PhD, and Knudson,Bill, PhD, 2012, May 14.

canned food

canned food

As can be seen in Table 2, for fruit products, the vitamin indices were notably higher for fresh products, and generally higher for frozen products, as compared to canned products. The authors of the study noted that fruits tended to exhibit larger variation in nutrient indices, possibly due to the level of processing required for many canned fruits, where canning involves adding syrup and sugars to the product.

The study concluded that since fresh fruits and vegetables are not available to consumers year round in many places, canning and freezing options can help consumers meet fruit and vegetable dietary recommendations throughout the year. Canned and frozen packaging plays an important role for American consumers, and is also a cost effective means toward meeting food security needs of low income households (Miller, Steven, PhD, and Knudson, Bill, PhD, 2012, May 14).

In Summary, studies have shown that for many fruit and vegetable products (especially for vegetables) processing via freezing and canning do not necessarily destroy the nutrient value of these foods, and in some cases, more nutrients are retained by processing some foods. This is because the canning process stops oxidation, which is a main cause of nutrient loss in fresh fruits and vegetables, and can even occur to some degree in frozen foods, according to the Michigan State University study. So, choosing the right kinds of canned food products, i.e., organic fruits/vegetables processed without added salt, sugar, or preservatives, might be a very healthy way to consume your fruits and vegetables.

References

CUESA. (2012). How Far Does Your Food Travel to Get to Your Plate? Retrieved from: http://www.cuesa.org/page/how-far-does-your-food-travel-get-your-plate

Miller, Steven, PhD, and Knudson,Bill, PhD. (2012, May 14). Nutrition & Costs Comparisons of Select Canned, Frozen and Fresh Fruits and Vegetables. Michigan State University. Retrieved from: http://www.cancentral.com/files/CMI_MSU_Analysis_Final.PDF

Rickman, Joy C., Barrett, Diane M and Bruhn, Christine M. (2007). Nutritional comparison of fresh, frozen and canned fruits and vegetables. Part 1. Vitamins C and B and phenolic compounds. J Sci Food Agric 87, 930–944. Retrieved from: http://ucce.ucdavis.edu/files/datastore/234-779.pdf

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