The conversion of optically pure isomer (enantiomer) into a mixture of equal amounts of both dextro and levo forms is called as

Depending on the rotation, molecules are called dextrorotatory (+) (d) or levorotatory (-) (l). Thus D-glucose is dextrorotatory but D-fructose is levorotatory. Equimolecular mixture of optical isomers has no net rotation (racemic mixture) or Racemization Ref: Textbook of Biochemistry for Medical Students, 7E (DM Vasudevan)(2013) Pg no.70 & 71.