Bioaccessibility, digestibility and nutritional properties of algae and Cyanophyceae as basis of their potential as functional food ingredients

Algae has been used as food for many years in Asian countries. However, as a result of globalization, migratory movements and new dietary trends, algae consumption is increasing in Western countries. The nutritional profile of algae makes it of great importance, as it provides large amounts of micronutrients and other components. Macronutrients, minerals, total phenolic contents, antioxidant properties and bioaccessibility of minerals of five different algae Wakame (Undaria Pinnatifida), Spirulina (Arthrospira platensis), Sea lettuce (Ulva lactuca), Sea spaghetti (Himanthalia elongata) and Nori (Porphyra umbilicales) were studied. Moreover, folates, chemical composition, amino acid, mineral content and fatty acid profile were also evaluated. Analyses reported high total fiber (57.82 g/100 g DW), insoluble fiber (21.08 g/100 g DW) and soluble fiber (36.71 g/100 g DW) content in Sea spaghetti, while Spirulina was found to have a high protein (64.71 g/100 g DW) and fat content (5.13 g/100 g DW). Regarding mineral content, Sea lettuce and Nori were the algae with the highest iron bioaccessibility; K, Na, Mg and P being the most abundant elements in the algae of this study. In reference to fatty acids, PUFAs (polyunsaturated fatty acids) were significantly higher in the five algae evaluated, than SFAs (saturated fatty acids) and MUFAs (monounsaturated fatty acids). With respect to the antioxidant capacity study, FRAP and ABTS methods showed that Sea spaghetti reported the higher antioxidant capacity (mainly due to the total phenolic content). However, with the ORAC method, a higher antioxidant capacity was obtained in Nori. Glutamic acid and asparagine were the predominate amino acids in all algae. Finally, the most abundant form of folate was folic acid (278.30-655.91 mu g/100 g DW) and 5-Formyl-5,6,7,8-tetrahydrofolic acid (51.71-318.02 mu g /100 g DW). In view of the results, the macroalgae and Cyanophyceae could be incorporated as functional ingredients into the diet. The important source of proteins, phenolics, minerals, PUFAs, folates and amino acid and make algae an excellent source of natural bioactive components to be included as ingredients in functional foods. However, it is somewhat difficult to add algae to a food, as algae contain some toxins, heavy metals and also some contribute strong characteristic marine odors and flavors that attribute sensory parameters such as astringency and bitter taste. But all these aspects can be controlled with the right dosage or concentration of seaweed.