Table 1.

The most important properties of the main carotenoids.

Component	Main Sources	Benefits	Limitations	Refs.
β-carotene	Carrots, sweet potatoes, tomatoes, apricots, squash, mangoes, yams, spinach, green peppers, green plants, and other fruits and vegetables.	Highest pro-vitamin A activity among the carotenoids, strong antioxidant that scavenges free radicals and reduces cancer, cataracts, infections, cardiovascular, and other chronic diseases, protects skin health, improves vision, strengthens immune system, and has immunomodulatory action.	Chemically unstable with high tendency for chemical degradation due to light, heat, and oxygen exposure due to large number of conjugated double bonds in its structure, high melting point, crystallinity at room temperature, extremely low water solubility, and very low (and variable) oral bioavailability (less than 10% from orally taken food).	[14,20,44,45]
Lycopene	Found in high concentrations in tomatoes, pink grapefruit, pink guava, papaya, and watermelon, also in apricots, barriers, plums, carrots, green peppers, red cabbage, passion fruit, and a large number of red-colored fruits, vegetables, and microorganisms.	Lycopene structure has a higher number of conjugated double bonds than other carotenoids, which makes it the most potent antioxidant among carotenoids (lycopene from watermelon had significantly higher antioxidant activity than from tomato). It possesses immunomodulatory and anti-inflammatory action, enhances immune system, prevents some types of cancer, cardiovascular, chronic, and degenerative diseases and hepatic fibrogenesis.	Chemically very unstable to oxygen, light, heat, and humidity exposure due to the presence of double bonds in its structure, easily oxidized and isomerized, destroyed at acidic pH, stable at basic pH, low water solubility induces low bioavailability, restricting its incorporation in different foods and beverages.	[3,14,44,46,47,48]
Lutein	Widely distributed in algae, fungi and bacteria, plants, especially in dark green leafy vegetables (broccoli, spinach, kale), orange-yellow fruits and vegetables (petals of the marigold flower, honeydew melon, mango, yellow corn, carrots, potatoes,) and egg yolks.	Lutein concentration is highest in the retina (~500 times higher than in other tissues), enhances eye health (proven retinal and macular protection against oxidative stress), maintains skin health, anti-diabetic, anti-obese, anti-cancer, anti-inflammatory antioxidant, antiatherogenic, anti-ageing, and immunomodulatory properties, prevents atherosclerosis, reduces prostate cancer risk.	Chemically unstable (sensitive to light, heat, pH, and oxidative stress, undergoes degradation due to interactions with other ingredients in the food matrix) crystalline at room temperature, very low water solubility, low bioavailability (in addition to the strongly hydrophobic nature of different nutrients, enzymes, and low pH in the GIT also decrease absorption), which all limit food and pharmacy applications.	[14,25,44,49]
Zeaxanthin	Egg, oranges, corn, honeydew melon, dark green leafy vegetables, bacteria.	Concentrated in macula prevents (as lutein) visual loss from age-related macular degeneration, prevents oxidation, cell and DNA damage, anti-ageing, prevents cardiovascular diseases, improves respiratory system and overall health.	Similar to lutein	[14,35,42]