A recent study conducted by Mexican researchers and published in the Food Research International journal has shown that traditional household cooking of pungent peppers can decrease their micronutrient content and reduce their free radical fighting abilities.
Popular Mexican peppers, such as Poblano, Bell, Chilaca, Caribe, Jalapeño, Serrano, Habanero and Manzano have a high vitamin C and carotene content – both powerful chemical substances that work by inhibiting oxidation and by eliminating the byproducts of oxidative stress. Carotenoids are pigments responsible for the yellow, orange or red colors of many fruits and vegetables (including peppers, apricots, etc) and beta-carotene specifically is the precursor of vitamin A – a substance needed by the retina of the eye. Free radicals, which result from oxidation, are tiny molecules that have been associated with the premature aging of cells, the development of cancers, and are thought to also play an important role in various neurodegenerative diseases.
While oxidation is a naturally occurring reaction that enables cellular energy transfer and is essential to all metabolic processes in our tissues, medical scientists believe that a diet rich in antioxidants, such as vitamin C and beta-carotene, may actively fight excess oxidation within our bodies. Aside from its antioxidant properties, vitamin C is known to play numerous important roles in the human body, such as preventing allergies, reducing the level of circulating pro-inflammatory cytokines and modulating gene expression. Regularly consuming raw peppers in salads and other fresh, raw dishes can significantly boost antioxidant intake, support long-term health and even assist the remedy of existing illnesses.
The study compared chemical evaluations of raw, boiled and grilled peppers and concluded that thermal preparation decreases vitamin C content with up to 87%, while carotene content may go down with as much as 45%. Antiradical compounds in pungent peppers have shown significant alterations as a result of heat treatment, with an impressive 93% loss after grilling. In fact, of all preparation methods tested, grilling was discovered to be the most damaging as far as pungent peppers are concerned, decreasing all nutrient values to less than half. Grilling also generated browning, an additional cause for concern, considering that it is the result of combustion - an oxidation process that can further increase our free-radical intake.
Comparing the two evaluated cooking methods, grilled peppers have shown considerable losses in weight (due to reduced water content), while boiled peppers retained their initial weight, but exhibited discoloring and structural changes. As many of the nutrients in peppers, including vitamin C and B-complex vitamins, are water soluble, the researchers involved in the study appreciated that during boiling, most of the nutrients in vegetables are lost in the water.