Physical and chemical properties of lycopene
1 the stability of lycopene
Because lycopene molecules conjugated double bonds in 11 and two non-conjugated double bonds, making the relatively poor stability of lycopene, can occur under certain conditions, cis-trans isomerization and oxidative degradation. Lycopene more sensitive to the oxidation reaction, the solution after 12 hours by sunlight, which basically wiped out of lycopene. Solution of Fe3 + and Cu2 + would be the photo-oxidation of lycopene act as a catalyst and other metal ions such as K +, Mg2 +, Ca2 +, Zn2 + and so is little effect, so the natural lycopene extract and in the application process should try to avoid the use of iron and copper containers. pH values ​​also have an impact on lycopene, lycopene, when dissolved in ethanol, and modulates the pH 1 to 14, the results indicate that lycopene unstable to acid, alkali is relatively stable, so the use of lycopene as a pigment time is not suitable for acidic drinks. Thus, the factors affecting the stability of lycopene oxygen, light, metal ions, pH, etc., so the lycopene extraction, storage, processing and analysis should be conducted in the environmental factors under controlled conditions.
 2 coloring ability of lycopene
Lycopene as a natural red pigment, how to maintain the strongest color strength is essential. Tomato Lycopene in exist in two states: most of which are slender, needle-like crystals form in the body color, showing bright red. When the formation of crystalline lycopene, the plastid membrane disappears, the pigment dispersed in the protoplasm free crystal, when viewed under a microscope, you can see a small colored granular body, indicating the apparent color of the colored body; another small part of the (10%) is the formation of complexes with proteins present in the cells. Lycopene exists in different forms have different colors and intensity, but also with different solvents and media show different colors. For example, dissolved in petroleum ether, lycopene yellow, in carbon disulfide in the red.
3 the solubility of lycopene
Lycopene is fat-soluble pigments, lipids and other soluble non-polar solvents, insoluble in water, insoluble in polar solvents such as methanol, ethanol, soluble in aliphatic hydrocarbons, aromatic hydrocarbons and chlorinated hydrocarbons such as ethane, benzene, chloroform and other organic solvents. Lycopene solubility in various solvents increases as the temperature increases, however, when the more pure samples, the dissolution of the more difficult. Lycopene crystals dissolve slowly, tend to form a super-saturated, although the increase in temperature can accelerate the dissolution, but the cooling crystallization may occur, then can use ultrasound to accelerate its dissolution. Although pure lycopene is insoluble in water, but when it combines with certain substances such as protein complex formation, then with high solubility.