Food Storage And Vitamin Losses

Let’s see what happens to vitamins during food storage periods, how vitamins in food can be lost or preserved at that time.

Fruits and vegetables are the main source of vitamins and other nutrients in our diet. The highest nutritional value of fruits and vegetables is in the first weeks after harvesting and in some cases only in first few days.

Most root vegetables (potatoes, sweet potatoes, carrots, onions, beets) may be stored for long periods in dark and cool places. We can use these vegetables for whole winter and spring, but we should remember that their nutritional value gradually decreases. In spring time the content of vitamins in these vegetables is much less than in fall.

For example, potatoes lose 50% of its vitamin C in two month after harvesting and almost 80% of vitamin C is lost after four month of storage. For many people potatoes are the main source of vitamin C during winter time and that's why we might develop deficiency of this vitamin in spring.

Other vegetables lose the most of their nutrients during first few days after they were picked from the field. For example, spinach which is very popular because of its valuable nutrients, lose 80% of its vitamins during first two days after harvesting even if it is stored in cool and dark place. If it is possible, use your spinach right after it’s picked, this way your body will get the most vitamins and other nutrients.

Here is another example -- fresh green peas. After harvesting they lose significant amount of its valuable nutrients within a week. Study has showed that 77% of vitamin C in fresh green peas was lost after seven days of storage.

Locally Grown Produce and Vitamins

Unfortunately, our vegetables that are bought at supermarket might not be as fresh as we think. In some cases they have been held for a month in warehouses after harvesting before they came to the store. This long period of food storage can lead to great losses of valuable nutrients in some vegetables.

So, what can we do today to get vitamin rich vegetables and fruits on our tables? This situation is not hopeless there are many ways to prevent vitamin deficiency in our diet.

We can buy vegetables and fruits grown locally right from local farmers. Many farmers allow you to pick yourself right from the field and that is even better, that way you’ll know for sure when it was harvested.

Every year I pick fresh vegetables, fruits and berries with my kids right from the fields of our local farmers. We have a lot of fun there and the taste of just picked tomato, cucumber or strawberry incomparable to those that are from the store! When we eat those fresh produce within first couple days we’re getting all their nutrients!

Are Fresh Vegetables Always Good for Me?

When fresh vegetables can’t be eaten in first days after harvesting, you may store it at deep freeze temperatures. Freezing of vegetables may preserve some of their nutrients from distraction. Studies have found that frozen vegetables in some cases contain more nutrients than fresh ones.

Scientists found that cooked frozen green peas contain higher levels of beta carotene than cooked fresh peas. Most frozen fruits and vegetables bought at supermarket were frozen very soon after harvest and it helps to minimize the loss of nutrients. Today we should agree that fresh vegetables are not always better for us, because of long food storage periods.

Which Vitamins are Most Unstable?

Vitamins are different in their stability. Vitamins B2, C and E are very unstable and very easily may be destroyed during storage periods, on the other hand vitamin B complex will stay in food for longer period of time.

Serious losses of vitamin E happen at deep freeze temperatures. After two month of storage in freezer, food loses around 75% of its vitamin E. Vitamin B5 slowly disappears from all types of food that are kept frozen.

Don’t get disappointed, these unstable vitamins you can get in other foods if fresh vegetables are not available.

The richest source of vitamin E considered not vegetables but nuts and vegetable oils, even if some vegetables contain this vitamin.

The best vitamin C source are fruits, green-leafed vegetables and juices. If you want to find out more about which foods contains which vitamins check my vitamins in food page.

About Greatest Natural Destroyers
of Vitamins in Food

Did you know that the greatest natural destroyers of vitamins in food storage are light, air and ambient temperatures? Most foods should be kept away from them. Great distraction of vitamins happens in milk when it’s left some time at full sunshine or even under shop lights.

Studies have showed that milk loses 90% of its riboflavin when it is left in sunshine for two hours; 45% in cloudy weather. Under room lighting milk loses 24% of its riboflavin within 24 hours.

By the action of light riboflavin is converted into lumiflavin and it can cause serious distraction of vitamin C in milk. Only 5 percent of lumiflavin can destroy 50 percent of the vitamin C content. To save vitamins in milk it should be transferred to a cool and dark place as soon as possible after delivery or collection.

Also, our bread is affected by light. Within 24 hours about 20 percent of riboflavin is destroyed by supermarket lighting. If bread was packed in bag that protects it from light than loss of that vitamin will lower by 2%.

Next natural destroyer of nutrients is the air. Vitamin C is the most unstable to air. Many people drink fruit juices for vitamin C, but after the container is opened this vitamin starts disappearing rapidly because of the air invasion. Studies indicate that during 3-4 weeks after opening a sealed bottle 90 percent of vitamin C had been lost in orange juice. In apple juice vitamin C is lost even more rapidly. After four days of storage 50 percent is lost; after two weeks 95 percent is destroyed.

Also, bruising of vegetables and fruits can lead to substantial losses of unstable vitamins because of the air penetration. When the wall of fruit or vegetable is damaged, it’s better to eat it as soon as possible because its nutrients are not protected from the air and light and are very rapidly destroyed.

We have discussed how vitamins can be lost during food storage periods and what we can do to prevent those losses. Now let’s make some conclusions:

Here you have learned how valuable nutrients in your food can be destroyed during food storage periods before it riches the kitchen. How vitamins may be lost or saved during cooking process you may find out in my Cooking Methods page.

SBI!