| 摘要 |
PURPOSE:To obtain the subject pigment, excellent in resistances to light and heat, color tone, and also excellent in yield and purity of color tone by extracting crushed purple sweet potato crushed at a low temperature with water, etc., under an acid condition. CONSTITUTION:Purple sweet potato cooled below 10 deg.C, preferably below -20 deg.C is crushed to a level of passing through 5-20mm screen using a cryomill, etc. Resultant crushed material is extracted with water and/or alcohol (e.g. lower alcohol such as methanol or ethanol) under an acid condition (pH is preferably at 2-3) at 20-60 deg.C to afford the objective pigment. |
