1. Curcumin food additive residue standard:
Curcumin, puffed food, coloring agent, suitable for production use
Curcumin, fried food, coloring agent, use in moderation according to production needs
Curcumin, food product filling, coloring agent, suitable for production use
Curcumin Sweet Juice Sweet Sauce, Compound Sauce Coloring Agent 0.1
Curcumin Instant noodles Coloring agent 0.5
Curcumin Jelly Colorant 0.01 (if used for jelly powder, increase the usage by double adjustment)
Curcumin carbonated drink coloring agent 0.01
Curcumin batter (such as batter for fish and poultry), breading, frying powder, coloring agent 0.3
Curcumin gum-based candy coloring agent 0.7
Curcumin Cocoa products, chocolate and chocolate products (including chocolate-like and chocolate-based chocolates) and candy colorants 0.01
2.Curcumin Identification test:
Solubility: Curcumin is insoluble in water and ether; soluble in ethanol and glacial acetic acid. Determined according to the OT-42 method. The melting range is 179 to 182 °C.
3. Determine according to the conventional method:
The ethanol solution of the color reaction A sample should be pure yellow and have a light green fluorescence; if this ethanol extract is added to concentrated sulfuric acid, a dark purple color will be produced. Color reaction B The aqueous solution or the dilute ethanol solution of the sample was treated with hydrochloric acid until it started to be slightly orange.
The mixture was divided into two portions, and a small amount of boric acid powder or crystal was added to one portion, and its color was significantly reddened compared to the portion without boric acid. It is also possible to immerse several pieces of filter paper in a solution of the pigment in ethanol, dry at 100 ° C, and then wet with a dilute solution of boric acid (with a few drops of hydrochloric acid). It should be cherry red after drying.
5 ml of curcumin test solution (0.01 g sample dissolved in 1 mL of 95% ethanol) was dropped on thin layer chromatography (microcrystalline cellulose, 0.1 mm) and placed in 3-methyl-1-butanol/ethanol/water. In the developing tank of the ammonia/4 (4:4:2:1) mixture, the solvent front edge is raised by 10 to 15 cm. After a day and night, it was observed under ultraviolet light: there were three yellow spots with Rf between 0.2 and 0.4; the other spots had an Rf of 0.6 to 0.8; all spots showed yellow fluorescence under ultraviolet light. The 6.95% ethanol solution has a maximum absorption peak at 425 nm.