Flavor is a combination of taste plus the other sensations that influence our perception of food, such as aroma, texture, juiciness, mouthfeel and color.
The five taste receptors
Receptors on our tongues and in our mouths send signals to our brains when we experience certain tastes. Salt and sour receptors are well understood, while bitter and sweet receptors appear to be more complex.
Umami oo-MOM-ee, known as the fifth taste, is described as meaty and savory or delicious (umami is derived from umai, the Japanese word for delicious). It is the taste of glutamates – the salts of an amino acid – and other small molecules called nucleotides. Although umami has been known for quite awhile, recently umami receptors have been clearly identified, so this is a bona fide fifth taste.
The ability to detect these five tastes has been key to our survival throughout the ages, directing us toward vital foods and away from potential poisons.
Sweet means energy-giving carbohydrates. Salt indicates essential minerals for life-sustaining cell functions and wound healing. Sour says to “proceed with caution,” since many foods sour as they deteriorate. Umami signifies life-giving protein. And bitter warns “spit it out, don’t touch it” because many natural toxins taste bitter.
The Amazing Umami Effect
The small protein compounds that trigger our umami receptors come from many sources. Meaty, savory umami flavors instantly bring to mind a great steak, but fruits and vegetables also contain these same proteins. Tomatoes, mushrooms, aged cheeses, green tea and seaweed all stimulate our umami receptors.
Part of umami’s great flavor power comes from synergism, or the fact that the whole is greater than the sum of its parts. When individual umami compounds are combined, they have a magnifying effect on each other. This explains the delicious pairings of mushrooms and steaks, and wine or tomato sauces with beef.
A 50-50 mixture of two umami compounds can produce eight times as much flavor as either one of the compounds alone!
In addition, ripening, aging and fermenting foods can dramatically increase their umami flavor compounds. That’s why a truly ripe tomato, aged Parmigiano-Reggiano and fermented foods, such as wine and soy sauce, possess enticing, complex flavors—and also pair well with beef dishes.
Three Natural Sources of Umami
The umami taste is produced by naturally occurring compounds – the amino acid glutamic acid, salts of glutamic acid (glutamates) and nucleotides. It’s no surprise that beef contains all three of these compounds. 
