Polyphenols as Natural Antioxidants: Sources, Extraction and Applications in Food, Cosmetics and Drugs

Antioxidants are able to scavenge free radicals that cause degradation of food, pharmaceutical and cosmetic products during processing and storage. Natural ingredients in food products are everywhere continually gaining popularity, and the use of plant extracts in cosmetic formulations are on the rise. Additionally, chemists, pharmacists and nutritionists are focusing on the development of new nutritional applications that target not only to disease prevention but also in improving skin health, appearance of the food product and overcoming any off flavors. This approach is the beginning of the new era where the products intended to promote well-being and health will be available to meet the consumers’ demands. Polyphenols are the most abundant natural antioxidants in nature commonly found in both edible and non-edible parts of plants, and they have been reported to have multiple biological effects, including antioxidant, antimicrobial, anti-viral, anti-inflammatory, analgesic and antipyretic activities. The extraction of polyphenols from plant sources has drawn increasing attention as a low-value source of antioxidants. Although the development in analytical techniques has played a significant role in the detection of a wide range of polyphenols, success still depends on the method of extraction. In literature, several combinations of solvent, temperature, extraction time and agitation speed have been presented in order to achieve maximum phenolic yields, but these conventional proposals are considered as burden on the environment due to the use of high temperatures for long periods of time and secondly due to the effect on the heat-sensitive components of polyphenols. Alternatively, the application of novel techniques such as ultrasound, pulsed electrical field, high-pressure CO2 and others is more welcoming due to their reduced usage of organic solvents, low operational temperatures, short processing times and better quality and yields with high selectivity toward targeted compounds. The extracts rich in phenolic compounds are attractive ingredients for food, cosmetics and pharmaceutical products due to their beneficial biological properties importantly their antioxidant potential. This chapter is aimed at discussing the extraction of polyphenols using environment-friendly techniques and to use these polyphenol-rich extracts in various food, cosmetic and pharmaceutical products.