Carotenoids are red-yellowish lyposoluble substances. They can be found in membrane cells and they are carried by lypoproteins. They are characterized by a high presence of conjugated double bonds, which are the cause of their color and of their instability; they easily oxidize to air and in presence of light and can be modified by the presence of acids. One really important carotenoid is f-carotene, the vitamin A precursor. A recent French research underlined the positive effect of antioxidants fortifications ф-carotene, zinc, selenium, vitamin E and vitamin C) on healthy aging for elderly people (Assmann, 2015).
Lutein and Zeaxantin
Lutein and its stereo-isomer Zeaxantin are one of the most important carotenoids in plasma. They reduce oxidative stress (Johnson, 2013) and they have anti-inflammatory properties. Moreover, they act as antioxidants for erythrocytes reducing markers of cellular membrane's lipidic oxidation (Kiko, 2012; Nakagawa, 2009). Their principal function regards the vision system, improving visual acuity and reducing age-related macular degeneration (AMD) (Puell, 2013). Fortifications with lutein and zeaxantin, together with other nutrients such as omega 3, show an increase of serum levels, an improvement in several objective measurements of visual and cognitive functions for elderly people (Bovier, 2014) and an increase of the macular pigment's density in infants. This last positive effect can be observed in presence of fortifications in motherly diets (Henriksen, 2013; Perrone, 2013).
New Technologies for Dairy Products Fortification 87