Monosodium glutamate crystals, differential interference contrast light micrograph. This preparation shows radial growth of the crystals. The food flavouring monosodium glutamate is a chemical salt made from glutamic acid and sodium. It is viewed as either enhancing the four standard tastes (sweet, salty, sour and bitter), or as a fifth taste that is called umami. Magnification: x25 when printed at 10 centimetres wide.