Presented below is a photomicrograph illustrating various textures seen in a thin section of hydroxymethyl pyrone crystallites. This digital image was captured with the DXM 1200 ACT-1 control software in single-image acquisition mode utilizing Hoffman modulation contrast and polarization.

Also known as kojic acid, hydroxymethyl pyrone is widely used in the medical field as a pain killer, and an anti-inflammatory drug. It has dermatologic applications, used as a protective agent against UV light, and to lighten pigment spots and discolorations on the skin by inhibiting the formation of pigment. In the food industry, this antioxidant is also used as a precursor of flavor enhancers and to inhibit discoloration in agricultural products (by inhibiting polyphenol oxidase).

Kojic acid (discovered by Saito, 1907) is produced by koji, a solid culture of the koji mold (Aspergillus oryzae) and is a metabolite that possesses antibacterial and antifungal activity. It is a by-product of koji, a preparation of steamed rice and A. oryzae organisms that is the first step in the production of sake -- Japanese rice wine. Koji molds are also to make Miso, a soy bean paste, Shoyu, soy sauce, Amasake, a sweet beverage and Shouchu, a distilled liquor.