Curcumin is orange-yellow crystalline powder, slightly bitter in taste, insoluble in water and ether, soluble in ethanol and propylene glycol, soluble in glacial acetic acid and alkali solution, reddish brown in alkaline state, and yellow in neutral and acidic state. According to OT-42 method. Melting range179 ~182℃.

Curcumin has strong stability to reducing agent and strong coloring, and it is not easy to fade after coloring, but it is sensitive to light, heat and iron ions, and has poor light resistance, heat resistance and iron ion resistance.

Because curcumin has two hydroxyl groups at both ends of the molecule, the yoke effect of electron cloud deviation occurs under alkaline conditions, so curcumin will change from yellow to red when the PH is greater than 8. Modern chemistry uses this property as an acid-base indicator.

Extended data:

Curcumin can be extracted from turmeric powder, that is, curcumin, which is a natural and non-toxic functional pigment. It is recognized by many countries that it can be added to food, medicine, cosmetics and other fields, and there is no limit on the dosage, but it is added according to the need.

Turmeric is irregular oval, cylindrical or hammer-shaped, often curved, and some of them have short forked branches, with a length of 2 ~ 5 cm and a diameter of1~ 3 cm. The surface is dark yellow and rough, with shriveled texture and obvious links, and circular branch marks and fibrous root marks. Solid, not easy to break, brown to golden yellow cross section, horny, waxy luster. The ring pattern of the endodermis is obvious, and the vascular bundles are scattered in dots. The smell is unique, and the taste is bitter and pungent.

Baidu encyclopedia-curcumin

Baidu encyclopedia-curcumin