Natural antioxidants in functional foods: from food safety to health benefits

Abstract

Oxygen is essential for metabolism but it may be highly damaging for both organisms and foods unless properly controlled. Among uncontrolled detrimental processes lipid oxidation (or oxidative rancidity) is one of the most relevant. Oxidative rancidity of foods is initiated by reactive oxygen species (ROS). ROS are also formed in living organisms as consequence of metabolic activity with potentially sided effects, though a certain physiological level of ROS is crucial for the regulation of cell functions. Oxidative stress is defined as a disturbance in the pro-oxidant/anti-oxidant balance and antioxidants of synthetic or natural origin may have an important role in the maintenance of this balance. Synthetic antioxidants are widely used in the food industry, however concerns about their safety have changed the interest to natural antioxidants which are presumed to be safe. Natural antioxidants such as tocopherols, ascorbic acid, rosemary extracts, lycopene and some flavonoids are now available to be added to foods in replacement of synthetic products. These antioxidants may reinforce the activity of the endogenous antioxidant systems providing extra protection against oxidative stress. Food preserved with added natural antioxidants can be considered as functional foods because these products can provide better health conditions to consumer.