What is the Difference Between Fresh, Frozen and Canned Vegetables?
In a perfect world it would be great to be able to eat nothing but fresh, locally grown produce, but that is easier said then done. It is also important to consider that the body’s ability to absorb different types of plant nutrients is such that for certain nutrients cooking is actually very important to free up some nutrients for absorption. A good example is the potent anti-oxidant Lycopene from Tomatoes which is much better absorbed from cooked tomatoes versus raw tomato fresh from the garden!
Fresh produce falls into two broad categories: Post-harvest ripened where it ripens during transport to final selling location or vine ripened if it is picked while ripe and sold nearby. Although it is counter-intuitive not all plants are more nutritious when vine ripened because many plants continue to create more nutrients AFTER being harvested meaning the highest nutrition for these plants would come if they were post-harvest ripened.
So the take home message is that vine ripened is not necessarily better and several studies have shown there to be little to no difference in nutrient content compared to post-harvest ripening.
There are many other factors that help determine nutrient content of produce including the quality of the soil and the weather where a plant grows so it can get complicated.
Frozen Produce is generally vine ripened with minimal processing. Most fruits and vegetables are blanched in hot water for a few minutes before freezing to inactivate enzymes that may cause unfavorable changes in color, taste and nutrition content.
Although the blanching process can leach out certain nutrients, frozen produce has very similar nutrition content to post harvest produce. The real challenge with blanching is that it can negatively impact taste – as we all know there are certain fruits and vegetables that only have the best flavor if they are fresh picked.
Canned Produce – is usually vine ripened, but this produce tends to be much more heavily processed. Blanching is the norm but added sugar, salt, flavor and colors also are often included. This can ruin a good thing and increase health risks.
Another challenge with canned produce is the cans themselves. Many can are lined with Bisphenol-A (BPA) which is a known carcinogen and can leach into the produce so always choose BPA free cans!
What should you eat?
The most important takeaway is to eat produce as much as possible – fruits and vegetables are critical for your health and very few Americans eat enough! When possible choose fresh or frozen, and when you purchase any food in a can make sure it is BPA free.