Define the term antioxidant• Substance that can delay the onset of oxidation, or slow down the rate at which it occurs. Examples of common naturally antioxidants and their sourcesAntioxidants sourcesVitamin C (ascorbic acid) - Found in citrus fruits,green peppers, broccoli,green leafy vegetables,strawberries and etc.Vitamin E (tocopherols) - Found in wheat germ, nuts, seeds, whole grains, green leafy vegetables, vegetables oils(conola) and soya beansß-carotene - Found in carrots,squash ,broccoli,sweet potatoes,tomatoes,kale,contaloupe,melon, peaches and apricotsSelenium - Found in garlic, fish, shellfish, red meat, eggs, grains and chicken.
The structural features of the major synthetic antioxidants in food.• All of them contain a phenolic group. C-OH joined directly to a benzene ring• Many contain a carbon atom bonded directly to three methyl groups on a central carbon atom which is known as tertiary butyl group [ C(CH3)3 ]• Both the phenolic group and the tertiary butyl group are free radical scavengers.• They react with and remove the free radicals involved in the oxidation of the food and thus prolong the shelf life.
• Advantages and disadvantages associated with natural and synthetic antioxidants.Advantages DisadvantagesNaturally occuring vitamin C, E, and Consumer perceive synthetic antioxidantscarotenoids reduce the risk of cancer and to be less safe as they do not occurheart disease by inhibiting the formation naturally.of free radicalVitamin C is vital for the production of Natural antioxidants are more expensivehormones and collagen. ans less effective than synthetic antioxidants and can also add unwanted colour and leave an after taste to foodß-carotene can be used as an additive in Synthetic antioxidants are classified asmargarine to provide it with a yellow food additives and need to be regulated bycolour and act as a precursor for vitamin A policies and regulation to ensure their safesynthesis use in food.They are believed to enhance the health Policies regarding the safe use andeffects of other foods and boost overall labelling of food additives may be difficulthealth and resilience to implement esp in develeping countries and across international boarders.
Antioxidants found in the traditional foods of different cultures that may have health benefits.• Vitamin C and carotenoids (fruits and vegetables)• Flavonoids [citrus fruits, green tea, red wine, oregano, dark cocoa and etc.]• Have been linked to lowering levels of LDC (low density lipoprotein) cholesterol and blood sugar levels which reduce high blood pressure and to prevent the development of cancerous cell.