Photochromic materials are substances that change color when exposed to visible light or ultraviolet light.Another major feature is that the color change can be undone and can be changed repeatedly.For example, paper coated with photochromic material is used as rewritable paper that can be written and erased with a light pen.However, since substances that are far from natural substances are used, the fields that can be used are limited from the viewpoint of safety to the human body and environmental load.

　Therefore, the research team has been considering the development of photochromic materials that utilize plant pigments so that they can be used in products that require high safety, such as cosmetics and toys.There are about 500 kinds of pigments called anthocyanins contained in various plants, and some of them have the property of changing the molecular structure by irradiation with light.Therefore, we efficiently extracted a type of anthocyanin contained in Kouryan, which is known as millet.Furthermore, as a result of making a solution in combination with a substance called polyol used in foods and cosmetics, we succeeded in making a photochromic solution that is colorless when not exposed to light and emits a bright red color when exposed to ultraviolet rays.It is also possible to make it into a gel or powder.

　The photochromic material developed this time is expected to be used in more products than before due to its high safety.For example, if it is used in cosmetics, it will be possible to change the hue indoors and outdoors.Also, it seems that food packaging and stationery and toys for children are being considered.