There a several types of red peppers on the market, and one of the more popular is the red bell pepper. In its raw state, the red pepper is very high in sugar and dietary fiber, vitamin A, vitamin B-6 and vitamin C. It also contains high levels of manganese, niacin, potassium, riboflavin, and thiamine. The red pepper is very low in saturated fat and sodium, and contains no cholesterol.
Effects of Roasting
When a red pepper is roasted, its intrinsic weight decreases from the loss of moisture content, so a roasted red pepper is slightly shriveled. However, the peppers should only roast for about five minutes. After this, you should put the roasted peppers into a food-quality plastic bag, close the top and leave them to steam until the flesh is cooked. This results in very little loss of nutrients. If anything, the nutrients of a roasted pepper become more concentrated.
Just half a cup of roasted red peppers provides you with nearly all your recommended daily amount of vitamin C. Vitamin C tends to be destroyed by cooking, but quick roasting methods will only reduce the vitamin content slightly. Roasted red peppers have not been cooked in water, which would leach away the vitamin C, so they retain much of the vitamin. The vitamin C content of 100 g of raw red pepper is 127.7 mg. The amount of vitamin C left in 100 g of red peppers that have been boiled is just 41.2 mg. Thanks to the reduced volume of roasted red peppers, their vitamin C content is actually higher than raw, at 162.8 mg per 100 g.
Provitamin A Carotenoids
The vitamin A in red peppers is found in its provitamin A carotenoids form. This produces the red color of the peppers. This vitamin A precursor includes beta-carotene, alpha-carotene, beta-cryptoxanthin, lycopene, lutein and zeaxanthin. These precursors need to be converted into the kind of vitamin A that your body can use, which is an inefficient biochemical process.
Vitamin A in the raw red peppers is identified as RAE, or retinol activity equivalents. Roasting or cooking alters this compound. Once red peppers are cooked, the vitamin A content can be measured in terms of its individual precursors.
Red peppers are very low in calories to begin with, but the effects of cooking increase their calories slightly. The calcium content in 100 g of raw red peppers is 7 mg, as opposed to 8 mg when they're cooked; iron, 0.43 mg compared to 0.52 mg when cooked; magnesium, 12 mg reduced to 7 mg when cooked; phosphorus, 25 mg reduced to 13 mg on cooking; potassium, 211 mg, was greatly reduced following cooking, to just 72mg; and sodium remained constant in both raw and cooked red peppers, at 4mg.