Lutein, as a natural plant pigment with multiple biological activities, has been widely used in food, drugs and cosmetics. However, due to its unsaturated structure, most of the lutein has poor water solubility and stability, easy degradation and inactivation, and low oral bioavailability, which greatly affects its efficacy. 1g of lutein is equal to 1g of gold, and is given the reputation of "plant gold".

1. Prevent obesity-related diseases

Lutein can inhibit the proliferation and differentiation of preadipocytes and play a role in lowering lipids. Specifically, it inhibits the activity of peroxisome proliferator-activated receptor-γ (PPARγ), a transcription factor responsible for the activation of adipocytes. Activation of PPARγ can down-regulate the expression of inflammatory factors, such as TNF-α, LP and interleukin-6 (IL-6), and induce the expression of adiponectin (an adipokine that sensitize liver and muscle to insulin), which in turn regulates insulin sensitivity, interferes with adipocyte differentiation, and exerts lipid-lowering effects.

2. Improve visual function in patients with age-related macular degeneration (AMD) and healthy people

Lutein is the main carotenoid in the macula, which can filter blue light into the human retina to a certain extent, effectively reduce visual damage, inhibit the activity of oxygen free radicals, and prevent the damage of oxygen free radicals to visual cells. The exact etiology of AMD is still unclear, and may be related to genetic factors, long-term light damage, metabolic and nutritional dysfunction. Lutein and zeaxanthin supplementation can improve the early dysfunction of central retina in patients with early AMD.

3. Reduce the risk of cardiovascular disease in healthy people

Lutein has good antioxidant capacity and can effectively inhibit oxidative stress response in the process of atherosclerosis, thereby reducing inflammatory response and oxidative damage to tissues and cells. High intake of lutein and high levels of lutein in blood or adipose tissue are associated with a reduced risk of cardiovascular disease.

4. Reduce UV-induced skin damage in normal people

Lutein has the function of anti-oxidation and inhibition of lipoxygenase, which can reduce erythema, aging, skin burns and even skin cancer caused by ultraviolet radiation on the skin.

5. Color egg yolks, poultry, and chicken feed

Lutein has strong coloring, which can increase the hatching of eggs and increase the reproductive rate of birds. In many countries and regions of the world, especially consumers in the United States and many Asian countries, due to habits and psychological effects, most people prefer golden or orangie-red egg yolks, like golden skin poultry, soft red meat, and often judge the nutritional value and freshness of eggs from the color of egg yolks. Consumers experience the yellow skin as a sign of better meat quality and flavor, which directly affects the price of the product. Therefore, in the modern poultry industry, feed companies in order to meet the needs of the market, often add excessive amounts of synthetic commercial colorants to the feed, which not only greatly increases the cost, but also is adverse to human health. Therefore, lutein is a natural pigment without side effects, which can be used to color egg yolk, poultry and chicken feed. Because of its safety and nutritional function meet the market demand, it is widely used in feed coloring in various countries.

6. Anti-cancer function

Lutein is a carotenoid with special physiological activity. It can inhibit the growth of human tumors and resist a variety of cancers, such as skin cancer, breast cancer, and colon cancer.

Oxygen

Because lutein contains many unsaturated double bonds and both violenone rings have hydroxyl groups attached, the most common cause of lutein degradation is oxidation. During drying of fruits and vegetables, when lutein is exposed to air, oxidation may occur, leading to the isomerization of lutein. Studies have found that in addition to the most basic epoxidation and hydroxylation of lutein during processing, the direct cleavage of lutein polyene chain will also form colorless small molecular compounds, and the biological activity of lutein will also be lost.

Temperature

Under heat treatment, the cell wall and membrane of spinach will be damaged, which will promote the dissolution of lutein. The all-trans conformation will partially change to the cis structure (9-cis and 13-cis lutein), which will reduce the stability of the all-trans conformation, leading to the degradation of lutein and the reduction of its biological activity.

PH

Under different pH conditions, lutein will produce different changes. Under extreme pH values below 4.0 or above 8.0, lutein will undergo deesterification and cis/trans isomerization, leading to degradation of lutein. Therefore, lutein is suitable for storage and reaction under neutral conditions.

Illumination

Light has obvious degradation effect on lutein, which is due to the accelerated oxidation of lutein molecular chain, the degradation and breakage of chromoplast, and the formation of low molecular weight compounds, which make lutein lose its color. At the same time, the conjugated polyene chain of lutein was deprotonated and lost electrons, while the stability of lutein was reduced.