Astaxanthin is a keto carotenoid with a variety of uses, including dietary supplements and food dyes. It belongs to a larger class of compounds called terpenoids (as a type of tetraterpenoid) and consists of five carbon precursors, isopentenyl diphosphate and dimethylallyl diphosphate. Astaxanthin is classified as lutein (originally derived from a word meaning “yellow leaf” because the yellow plant leaf pigment is lutein in the carotenoid family), but is currently used to describe oxygen Component, hydroxyl (-OH) or ketone (C=O) carotenoid compounds such as zeaxanthin and canthaxanthin. In fact, astaxanthin is a metabolite of zeaxanthin and/or canthaxanthin, containing hydroxyl and ketone functional groups. Astaxanthin, like many carotenoids, is a fat-soluble pigment. Its reddish-orange color is due to an extended chain of conjugated (alternating double and single) double bonds at the center of the compound.
Astaxanthin is a hemoglobin that is naturally produced by the freshwater microalgae Haematococcus pluvialis and the yeast fungus Xanthophyllomyces dendrorhous (also known as Phaffia). When seaweed is stressed by nutrient deficiencies, increased salinity, or excessive sunlight exposure, it produces astaxanthin. Animals that eat algae, such as salmon, red trout, red snapper, flamingos, and crustaceans (i.e. shrimp, krill, crab, lobster, and crayfish), also reflect red-orange to varying degrees of astaxanthin pigment.
Astaxanthin is also available as a dietary supplement for human, animal and aquaculture consumption. Industrial production of astaxanthin comes from plant or animal and synthetic sources. The U.S. Food and Drug Administration has approved astaxanthin as a food coloring (or color additive) for specific uses in animal and fish foods. The European Commission considers it a food dye and gives it the E number E161j. Astaxanthin is derived from algal, synthetic and bacterial sources and is generally recognized as safe by the FDA (GRAS). The European Food Safety Authority set the acceptable daily intake for 2019 at 0.2 mg per kilogram of body weight. Astaxanthin and astaxanthin dimethyldisuccinic acid are used as food coloring additives only in salmon feeds.
Astaxanthin is present in most red aquatic organisms. Its content varies from species to species and from individual to individual, as it is highly dependent on diet and living conditions. Astaxanthin and other chemically related shrimp-carotenoids are also found in many lichen species in the Arctic.
In the aquatic food chain, algae are the main natural source of astaxanthin. The microalgae Haematococcus pluvialis appears to be the alga with the highest accumulation of astaxanthin in nature and is currently the main industrial source for natural astaxanthin production, with over 40 grams of astaxanthin being obtained from one kilogram of dry biomass white. The production advantage of Rhodococcus pluvialis is that its numbers double every week, which means scaling up is not a problem. Specifically, the growth of microalgae is divided into two stages. First, in the green stage, cells are given abundant nutrients to promote cell proliferation. During the subsequent red stage, cells are deprived of nutrients and an envelope (carotenegenesis) is induced under intense sunlight, during which time cells produce high levels of astaxanthin as a protective mechanism against environmental stress. Cells containing high concentrations of astaxanthin were then collected.
Phaffia xanthophyll dendrites exhibit 100% free, non-esterified astaxanthin, which is considered advantageous because it is readily absorbed and does not require hydrolysis in the fish’s digestive tract. Compared with artificial astaxanthin sources and bacterial astaxanthin sources, yeast astaxanthin sources mainly consist of (3R, 3’r)-forms, which are important sources of natural astaxanthin. Finally, the geometric isomer all-E was higher in yeast sources compared to synthetic sources.
In shellfish, astaxanthin is concentrated almost exclusively in the shell, there is only a small amount of astaxanthin in the meat, and most of the astaxanthin is only visible during cooking because the pigment is separated from the denatured protein bound to the astaxanthin . Astaxanthin is extracted from Antarctic krill and shrimp processing waste. 12,000 pounds of wet shrimp shells yields 6-8 gallons of astaxanthin/triglyceride oil blend.
Astaxanthin biosynthesis begins with three isopentenyl pyrophosphate (IPP) molecules and one dimethylallyl pyrophosphate (DMAPP) molecule, which are bound by IPP isomerase and converted to incense by GGPP synthase. Folyylgeranyl pyrophosphate (GGPP). Then, the two molecules of GGPP are coupled by octaene synthase to form octaene. Next, lycopene desaturase forms four double bonds in the lycopene molecule to form lycopene. After desaturation, lycopene cyclase first converts the ψ end of lycopene to the β ring to form γ-carotene, and then converts the ψ end to β-carotene. From beta-carotene, hydrolase (blue) is responsible for the inclusion of two 3-hydroxyl groups, and ketolase (green) is responsible for adding two 4-ketones, forming multiple intermediate molecules until the final molecule astaxanthin is obtained.
The synthetic structure of astaxanthin was introduced in 1975. Almost all commercial astaxanthin used in aquaculture is produced synthetically, with an annual turnover of more than US$200 million, and as of July 2012, it sells for around US$5,000-6,000 per kilogram. The market grew to over $500 million by 2016 and is expected to continue to grow with the aquaculture industry.
Using isophorone, cis-3-methyl-2-penten-4-yn-1-ol and symmetric c10-dialdehyde as raw materials, an efficient compound was synthesized and used in industrial production. It combines these chemicals with ethylation followed by a Wittig reaction. Combining two equivalent ylides with the appropriate dialdehyde in methanol, ethanol, or a mixture of the two can yield astaxanthin as high as 88%.