Thekey difference between astaxanthin and zeaxanthinis that astaxanthin is a redpigmentthat can be found in marine animals and microorganisms, whereas zeaxanthin is a yellow pigment found in vegetables and fruits.
Astaxanthin and zeaxanthin are two important pigments that can be found naturally in the environment. They have different chemical and physical properties.
What is Astaxanthin?
Astaxanthin is a type of keto-carotenoid with various uses. It is used as a dietary supplement and food dye. This compound belongs to a large class of chemical compounds that are namedterpenes. We can classify this compound under xanthophyll. But currently, it is considered acarotenoid compoundconsisting of oxygen-containing components such as hydroxyl or ketone groups.
The chemical formula of astaxanthin is C40H52O4. The molar mass of this compound is 596.84 g/mol. It appears as a solid red powder having a density of 1.07 g/cm3. Its melting point is 216 degrees Celsius, and its boiling point is about 774 degrees Celsius.
Naturally, astaxanthin occurs as a blood-red colored pigment produced naturally in freshwatermicroalgaeHaematococcus pluvialisand in some yeast. When the algae face a shock due to a lack of nutrients, increased salinity, or excessive sunshine, the species will create astaxanthin. Therefore, animals who eat this alga eventually reflect red-orange astaxanthin pigmentation to various degrees. Such animals include flamingos, red sea bream, crustaceans, salmon, and red trout.
Astaxanthin shows structural isomeric configurations. Besides, it also has two chiral centers at the 3- and 3’-positions. This results in three unique stereoisomers. These three isomeric forms can be found in nature, but relative distribution varies considerably from one organism to another. The two predominant forms of astaxanthin are named esterified form and non-esterified form. The non-esterified form can be found in yeast and synthetic sources. The esterified form can be found in algal sources. Moreover, these forms have different lengths of fatty acid moieties having compositions that are influenced by the source organism and growth conditions.
What is Zeaxanthin?
Zeaxanthin is a common carotenoid in nature that is useful in the xanthophyll cycle. It is the pigment that gives paprika its color. This compound is synthesized in some plants and in some microorganisms. E.g. corn, saffron, goji, and many other plants and microbes.
The chemical formula of zeaxanthin is C40H56O2. Its molar mass can be given as 568.8 g/mol. It appears in orange-red color, and the melting point is 215.5 degrees Celsius. Moreover, it is insoluble in water. It occurs mainly in the leaves of green plants. There, they help to modulate light energy and sometimes serve as a non-photochemical quenching agent that deals with tripletchlorophyll. This chlorophyll is overproduced at high light levels during photosynthesis.
Since lutein and zeaxanthin have identical chemical formulas, they are isomers. But they are not stereoisomers. Lutein differs from zeaxanthin according to the location of the double bond in one of the end rings. Therefore, lutein has three chiral centers, but zeaxanthin has two. Since symmetry is the same, the two stereoisomers of zeaxanthin are identical, so zeaxanthin has only three stereoisomeric forms. The stereoisomer is named meso-zeaxanthin.
What is the Difference Between Astaxanthin and Zeaxanthin?
Astaxanthin and zeaxanthin are two types of pigments. The key difference between astaxanthin and zeaxanthin is that astaxanthin is a red pigment that can be found in marine animals and microorganisms, whereas zeaxanthin is a yellow pigment found in vegetables and fruits.
The below infographic presents the differences between astaxanthin and zeaxanthin in tabular form for side-by-side comparison.
Summary – Astaxanthin vs Zeaxanthin
Astaxanthin is a type of keto-carotenoid that is used as a dietary supplement and food dye. Zeaxanthin is a common carotenoid in nature that is useful in the xanthophyll cycle. The key difference between astaxanthin and zeaxanthin is that astaxanthin is a red pigment that can be found in marine animals and microorganisms, whereas zeaxanthin is a yellow pigment found in vegetables and fruits.