It is a difficult task these days to find food on a supermarket shelf which has not been processed or refined in some way which would deplete its vitamin content or, in some cases, almost destroy it.
In all fairness to food processors, they are trying. Fruits and vegetables are processed, packed and sealed within a few hours of being picked. And, to be strictly honest, there is sometimes a greater vitamin loss through poor handling and cooking methods in the home kitchen than there is in the food processor's factory.
Most unopened tinned and frozen foods actually have the same nutritional value as fresh foods correctly cooked at home, although they usually have added sugar and salt and they certainly don't taste as good. The problem with tinned and frozen foods arises when they are taken from their packaging. The particles of ice clinging to frozen foods have a high vitamin content which is likely to be lost. And the liquid in a tin of vegetables probably contains about a third of the water soluble vitamins! If you throw it away, as most people do, the vitamins are gone forever.
Fruits and Vegetables
For all the sophisticated packaging you see on supermarket shelves you would have to admit that Nature has done her own packaging better than anyone. The banana "skin", the orange "peel" - there isn't a manufacturer in town who could do better.
Time is the critical factor in keeping vitamin loss in fruit and vegetables to a minimum. In fact, fruit and vegetables begin to lose their vitamin content the moment they are picked.
It is vital that fruits and vegetables are transported quickly from the producer to the shop so that they retain maximum vitamin content at the point of sale. Correct storage and refrigeration during transport is also essential.
The shopper's dilemma is how on earth can he or she know how much time it has taken for the produce to reach the store and whether or not it has been correctly handled.
Of course, there is no way of knowing precisely but fortunately there is a direct relationship between what "looks and tastes good" and a high retention of vitamin content.
Provided they are correctly handled during the picking and marketing process there is no evidence that fruits or vegetables lose much of their vitamin content before they get to the shop.
Ideally, the way to get the best vitamin value out of fruit and vegetables is to eat them raw.
If you are cooking, really fresh vegetables are preferable to frozen vegetables. Tinned vegetables come a poor third even if you use the liquid.
Because it is so important it is worth repeating that vitamin C, the main vitamin in fruits and vegetables, is more easily lost or destroyed than any other vitamin. It can be lost when cooked in water (it is one of the water soluble vitamins) and also destroyed by heat.
Food Handling Tips
- Although it is often necessary to remove or trim some of the outer leaves of vegetables because they are damaged, remember that the dark green leaves generally contain more vitamins than the lighter, inner leaves.
- Keep vegetables in the refrigerator (except potatoes and onions) where the temperature will help preserve vitamins - but cook them within two or three days.
- Don't buy vegetables and fruit in bulk and store them in the refrigerator for a lengthy period. (Refrigerated greens lose about half their vitamin C after five days.) The vitamin content of frozen beans is higher than that of fresh beans kept in the fridge for a week.
- Wash fresh vegetables - but don't soak them. The C and B vitamins they contain are water soluble and a lot of them could end up down the kitchen plughole.
- Don't thaw frozen vegetables before cooking - some of the vitamin content will be lost in the thawed water you throw away.
- Keep bottled milk out of the light - or the vitamins A and riboflavin (B2) it contains will be destroyed.
- When fruit is bruised, or vegetable leaves are crushed or wilted, a protein substance in the food is released, killing vitamin C.
- Don't prepare a salad until minutes before you're ready to eat it. Cut fresh vegetables lose vitamins quickly.
- Don't leave the baby's fresh squeezed orange juice lying around in the bottle too long - the vitamin C will soon disappear.
4 Basic Rules for Getting your Vitamins
- When buying food choose the type and variety carefully - plan for a balanced diet.
- Be aware how food processing, refining, storage and preparation can affect the vitamin content of foods.
- Store and handle food at home in the correct way.
- Use cooking methods that retain the maximum vitamin content.
Healthy Cooking Tips
The three most important cooking rules for retaining the maximum vitamin content of foods are:
- Use as little water as possible.
- Cook for the shortest possible time. Frozen foods require an even shorter cooking-time since they have already been blanched (cooked at a very high temperature for a very short time) before being frozen.
- Keep cooking temperature low.
The most significant fact in the cooking of food is the fact that many vitamins are water soluble, i.e. they dissolve in water. All the vitamin B complex group are water soluble and so is vitamin C.
Fortunately, there is now a popular trend towards eating crisp, just cooked vegetables - as distinct from the soggy, overcooked vegetables that were standard fare in grandma's time.
- The Chinese method of stir-fry cooking vegetables in a very small amount of oil is excellent for maximum vitamin retention.
- Potatoes baked or boiled in their jackets retain more vitamins than when peeled before cooking.
- Don't cook vegetables in copper or iron pots. Copper can kill vitamin C, vitamin E and folic acid. Iron kills vitamin C. The best types of saucepans are aluminum, glass and stainless steel.
- Don't discard the water you've cooked the vegetables in - its loaded with vitamins (C and B) that have been dissolved from the vegetables.
- Use the water as the basis for stocks, soups, sauces and gravies. The same principle applies to the liquid from tinned vegetables. Frozen foods that can be cooked in the plastic containers in which they are sold retain more of their vitamin content. In this way vitamins cannot dissolve in cooking water.
- Reheated already cooked vegetables which have been kept in the refrigerator for two or three days will have only about 30 to 50% of the vitamin C they contained when freshly prepared. Don't add bicarb-soda (an alkaline) while cooking green vegetables such as beans or peas. Bicarb, a deceptive cooking additive much favored in our grandmother's time, retains the fresh-picked, bright garden green color but kills the vitamins at the same time.