Monascus red is a natural red pigment made from rice and soybean as the main raw materials in liquid medium, through liquid fermentation culture, extraction, concentration and refinement of Monascus and Aspergillus purpureus. Monascus red has strong heat resistance and acid resistance, and its alcohol solution is quite stable to ultraviolet light. Slightly odorous, soluble in neutral and alkaline aqueous solution. In the medium below pH 4.0, the solubility is reduced, and it is easily soluble in ethanol, propylene glycol, propylene glycol and their aqueous solution. Stable to the pH of the environment, almost not affected by metal ions (Ca 2+, Mg 2+, Fe 2+, Cu 2+) and 0.1% hydrogen peroxide, vitamin C, sodium sulfite and other oxidants, reducing agent. Monascus red is very good for protein coloring, once dyed, that is, it does not fade.