The human tongue can detect five distinct tastes: sweet, salty, sour, bitter and umami.

CNN: Sweet! Researchers' device 'tastes' sweeteners

Other airlines have been increasing their use of umami, which is one of the five basic tastes discovered by the Japanese (together with sweet, sour, bitter and salty).

BBC: A possible end to plane food

It can be described as a shortcut to umami, the so-called fifth flavor (in addition to sweet, sour, bitter and salt), which in turn is often described as savory or meaty.

FORBES: Flavor Bomb - The New Chef's Secret Ingredient You Can Use Too

Ketchup ignites the palate as one of the few foods to stimulate all five sensations inside the mouth: salty, sweet, sour, bitter and umami, the latter of which gives body to food and is the savory taste found in cured meat and MSG.

FORBES: Companies, People, Ideas

Their research was complicated by the fact that of the five primary taste sensations salty, sweet, sour, bitter, and umami the taste of salt is the least understood.

NEWYORKER: Snacks for a Fat Planet

Remember you, want to hit sweet, sour, salty, bitter, and umami.

FORBES: How To Taste Spirits

Such a meal also should balance tastes savory, a little sour or bitter maybe, perhaps some sweet and salt and textures, from chewy to succulent to crisp.

NPR: The Art Of Sandwich-Making