Accumulating scientific evidence on the relationship between diet and health has demonstrated that food products with beneficial components can improve the state of well-being and reduce the risk of common diseases. A growing number of health conscious consumers have created a demand for food products with health promoting benefits. Therefore, search for new ingredients with biological activity from natural resources is gaining great interest among researchers.
Marine macroalgae have a long history of use as food and folk medicine in Asia and are traditionally well-known for their versatile health benefits. Marine algae are not only a rich source of dietary fibre, proteins, vitamins, and minerals, but also contain a great variety of secondary metabolites with diverse biological activities, which cannot be found in terrestrial plants. Therefore, the potential application of seaweed as a source of functional additives with health beneficial properties is a new target for exploration. In recent years, a number of potent antioxidant compounds have been isolated and identified from different types of edible seaweeds. In particular, phlorotannins (polyphloroglucinol phenolics) derived from brown algae have been shown to possess multiple physiological activities such as antioxidant, anticarcinogenic, antibacterial, anti-inflammatory, and anti-allergic properties (Table 42.1). Other bioactive compounds of importance in macroalgae are sulphated polysaccharides, dietary fibre, polyunsaturated fatty acids (PUFA), sterols, carotenoids, and โฃ-tocopherol [1]. This chapter discusses recent investigations on functional and nutraceutical ingredients from marine algae, with emphasis on the biological activities of algal polyphenols and sulphated polysaccharides.
Functional and nutraceutical properties of polyphenols from marine algae
42.2.1 Occurrence and chemical structure of algal polyphenols
Marine macroalgae are a rich source of polyphenols. A series of phenolic compounds such as catechins (e.g. gallocatechin, epicatechin, and catechin gallate), flavonols, and flavonol