"Vitamin C declines swiftly after harvest and continues to deteriorate throughout storage," explains Dr. Diane Barrett, a food chemist at UC Davis. She claims that vitamin C losses in vegetables kept refrigerated for 7 days after harvest range from 15% for green peas to 77% for green beans. Vitamin C is lost more slowly in frozen vegetables.
When cooking vegetables, it's important to eat them while they are still crisp and fresh. Cooked vegetables lose their vitamin C content rapidly once they are cooled down. For this reason, you should always add salt during the cooking process - which brings out the flavor of the vegetable instead of masking it like in the case of raw salads- rather than at the end when you season your dish.
Vitamin C can be preserved by either pickling or freezing but the results are not very stable. Other factors such as pH level and type of container used may also affect the stability of the vitamin.
Vitamin C was first discovered by Albert Karger in 1898. He called it "corium vitaminicum" which means "vital skin substance".
According to a 2007 study published in the Journal of Science of Food and Agriculture by the University of California Davis, vegetables lose 15 to 77 percent of their vitamin C content within a week of harvest. And that's assuming they're kept cold the entire time! Heating or freezing vegetable tissue reduces its vitamin C content.
You can increase the vitamin C content of your vegetables by cooking them until just tender and then covering them with an acid such as lemon or lime juice before serving. This will help preserve some of the vitamin C.
Some vegetables are more resistant to losing their vitamin C content than others. For example, studies have shown that broccoli and cauliflower retain nearly 100 percent of their vitamin C content after being cooked. Asparagus has been shown to retain 93 percent of its vitamin C content after cooking.
Vitamin C is lost during cooking because the heat breaks down its chemical structure, reducing its activity. However, the vitamin C present in vegetables does not change significantly when cooked at low temperatures for a long time. For example, frozen vegetables retain most of their vitamin C content after cooking.
After you cook vegetables, let them cool completely before storing in the refrigerator. This will allow any moisture to evaporate which will help prevent mold growth.
Cooking vegetables loses their vitamin C content over time.
Canned and frozen vs. fresh According to research, fresh items are preferable to processed products in terms of vitamin C concentration as long as they are handled at correct temperatures and endure little storage. However, vitamin C declines immediately after harvest and continues to decay throughout storage. As a result, its level can be higher in processed products than in their fresh counterparts.
The best sources of vitamins A, B6, B12, D, E, and K are dairy products, followed by meat, fish, eggs, vegetables, and fruits. It is important to note that not all foods that claim to be rich in certain vitamins are actually high in them. For example, spinach has more than 100 percent of the daily value for vitamin K but only contains about 15 percent of the daily value for vitamin A. Likewise, oranges have more than 200 percent of the daily value for vitamin C but only 7 percent of the daily value for vitamin A.
Vitamins are absorbed through the stomach and intestines. Therefore, it is important to eat foods that are well cooked or raw when recommending these substances for treatment or prevention. Also, it is advisable to avoid taking vitamins with meals that contain much protein because their absorption is reduced thereby requiring larger doses. Finally, keep in mind that some medications and other supplements you take may affect how your body absorbs vitamins from food.