METHOD OF PREPARING BLACK COLORANT OF NATURAL ORIGIN Russian patent published in 2000 - IPC

FIELD: food, cosmetic and pharmaceutical industries. SUBSTANCE: peel of green walnut is dried to moisture content of not higher than 20 wt %, grinding is conducted in two steps: coarse grinding and ultradispersive grinding. In first step, peel of green walnut is finely divided to particle size of not greater than 0.5-1 mm. Subsequent repeated ultradispersive grinding is carried out, and product is simultaneously further dried in vortex mill at gas stream of temperature of not higher than 80-95 C to obtain particle size of not greater than 50 mcm and moisture content of 2-3 wt %. Ultradispersive powder of black colorant is further extracted with water for at least 30 minutes at boiling temperature. The resulting product is allowed to settle and is filtered. Preserving agent is added to the resulting liquid extract. During extraction process, mixture of ultradispersive powder with water is further exposed to vibroacoustic field. Liquid extract of black colorant is subjected to spray drying. Invention makes it possible to prepare black colorant and to use it for coloring both food products and cosmetic agents and to increase yield of colorant. EFFECT: more efficient preparation method. 4 cl, 7 ex, 1 tbl