Aqueous leucoindigo solution comprising an aromatic amine, in particular aniline or aniline and N-methylaniline, wherein the concentration of the aromatic amine is below 200 ppm, wherein the leucoindigo salt in the solution is in the form of a mixed sodium and potassium salt, wherein the molar ratio of sodium to potassium is in the range of from above 3:1 to 10:1, preferably wherein the concentration of the salt is in the range of from above 25 to 45% by weight, based on the total weight of the solution.

The present invention relates to near-infrared-absorbing dye-based composite particles which exhibit a photothermal effect and/or photoacoustic signal upon photoirradiation, a preparation method thereof, and a use thereof. The near-infrared-absorbing composite particles comprise: a water-insoluble salt of a near-infrared-absorbing dye, which comprises anions of the near-infrared-absorbing dye and metal cations capable of forming a precipitation product with the anions of the near-infrared-absorbing dye; and particles of a polymeric surfactant, in which a water-insoluble salt of the near-infrared-absorbing dye is supported in the hydrophobic part of the polymeric surfactant.

Stable aqueous leucoindigo solution comprising an aromatic amine in the form of aniline or aniline and N-methylaniline, wherein said leucoindigo is in the form of an alkali metal salt; wherein the concentration of the aromatic amine is below 40 ppm determined according to ISO 14362-1:2017(E); and wherein the concentration of the leucoindigo salt is in a concentration range of from 10 to 45% by weight based on the total weight of the solution, and wherein the stability of the solution is measured at a temperature of 23° C.; or wherein the concentration of the leucoindigo salt is in a concentration range of from 45 to 65% by weight based on the total weight of the solution, and wherein the stability of the solution is measured at a temperature of 60° C.

The present application provides black perylene pigment microparticles having an average circularity of 0.8 or more which are amorphous; and a method of producing the black perylene pigment microparticles, which comprises a step of mixing a pigment solution in which a black perylene pigment is dissolved and a precipitation solvent for precipitating black perylene pigment microparticles from the pigment solution to form black perylene pigment microparticles, wherein at least one of the pigment solution and the precipitation solvent independently includes a salt of an alkaline earth metal and/or a particle growth inhibitor. The present invention can provide black perylene pigment microparticles having good dispersibility, high concealability and light-shielding property and controlled hue and chroma, and a method of easily producing the same, and the like.

The present application discloses methods for extracting melanin from a fungus, where the fungus is Inonotus obliquus (chaga), Fomes fomentarius, Ganoderma tsugae, or Phellinus igniarius. In the methods, a sample of the fungus is dried and pulverized to form a powder sample. The powder sample is refluxed in a sodium hydroxide solution to form a mixture. The mixture is separated into a liquid portion and a solid portion via centrifugation or vacuum filtration, resulting in the liquid portion including the melanin extract. The separated liquid portion including the melanin is acidified with a hydrochloric acid solution to precipitate the melanin. The precipitated melanin is then isolated via centrifugation or vacuum filtration such that the melanin collects as the pellet or precipitate. The melanin precipitate is then purified by washing with dilute HCl and deionized, distilled water. The purified melanin is then dried to produce the extracted fungal melanin.

The present invention is directed towards natural colorants comprising a material selected from the group consisting of genipin, purified genipin, pre-genipin compounds, iridoid compounds, genipin deriviatives, a genipin-containing substance, and combinations of any thereof; and a primary amine containing compound. Processes of making natural colorants are further disclosed. Additionally, processes of producing a desired color of natural colorants are disclosed.

An object of the present invention is to provide a method for removing geniposide or genipin or both from a material containing geniposide or genipin or both. The present invention is a method for removing geniposide or genipin or both from a material containing geniposide or genipin or both, the method comprising treating the material containing geniposide or genipin or both using an activated carbon having (a) a methylene blue adsorption ability of 50 ml/g or more; and (b) an iodine adsorption ability of 750 mg/g or more, thereby removing geniposide or genipin or both.

The present invention relates to a valuable product in the form of a flavonoid-containing phenol mixture having intense red coloration and to a method for obtaining a valuable-substance phase, more particularly a red-colored phase, from a native substance mixture.

Stable aqueous leucoindigo solution comprising an aromatic amine in the form of aniline or aniline and N-methylaniline, wherein said leucoindigo is in the form of an alkali metal salt;

wherein the concentration of the aromatic amine is below 40 ppm determined according to ISO 14362-1:2017(E); and
wherein the concentration of the leucoindigo salt is in a concentration range of from 10 to 45% by weight based on the total weight of the solution, and wherein the stability of the solution is measured at a temperature of 23 C.; or
wherein the concentration of the leucoindigo salt is in a concentration range of from 45 to 65% by weight based on the total weight of the solution, and wherein the stability of the solution is measured at a temperature of 60 C.

The present invention relates to methods for obtaining natural colorants from materials of plant origin. The method comprises a mixing step, a co-pigmentation step, an enzymatic hydrolysis step and various filtration steps carried out under specific conditions.