Final answer:
Antioxidants such as vitamins C and E, and provitamin β-carotene, found typically in fruits and vegetables, play a crucial role in protecting living tissues from oxidative damage by neutralizing harmful free radicals. They are also used as food preservatives to prevent food deterioration due to oxidation.
Step-by-step explanation:
Compounds typically found in plant foods that significantly decrease the adverse effects of oxidation on living tissues are known as antioxidants. These substances, such as vitamins C and E, as well as provitamin β-carotene, function by neutralizing free radicals, which are harmful molecules with unpaired electrons. Free radicals can be formed through metabolic processes and environmental factors like radiation and pollution. When the body's natural defense mechanisms, including detoxification within the peroxisome and cellular antioxidants, are overwhelmed, antioxidants from the diet become especially important. Antioxidants are found primarily in fruits and vegetables and can inhibit the oxidation that would otherwise cause damage to cell membranes by counteracting reactive oxygen species (ROS). For example, vitamin C is oxidized in the process of protecting cells to become dehydroascorbic acid, thereby halting the potential damage. Besides, tocopherols (vitamin E) protect cell membranes from oxidative damage and ensure the integrity of polyunsaturated fatty acids. These nutrients not only protect our body tissues but are also used as food additives to preserve freshness and prevent the deterioration of food by oxidation.