Letter U

UGNI BLANC:
(ref nec) White grape variety cultivated in Cognac under the name of Saint-Emilion.

ULTRASOUND (molecular gastronomy):
(TLFi) Acoustic vibration with a frequency exceeding 20,000 hertz, which is not perceptible to the human ear. Pressure waves (related to sound) that can deliver a significant amount of energy to food. If a probe is placed in a mixture of egg yolk, vinegar, and oil, a mayonnaise sauce is obtained. More generally, ultrasonic probes are used by all physicochemical laboratories to make emulsions, and one wonders why they are not more widespread in the kitchen.

UMAMI  (a term not to be used):
(H. This) According to producers of monosodium glutamate, this is the flavor of this compound, but:
- the perception of monosodium glutamate is genetically variable, with some perceiving a sweet flavor, others a salty flavor, and still others a flavor reminiscent of chicken broth;
- the same people who sell MSG argue that umami is the flavor of dashi, broths made from kombu seaweed, whose flavor is not unique, since it is that of glutamic acid and alanine.
It is therefore best to avoid talking about umami , and instead, one can talk about all the flavors of all the amino acids present in food.
And, in any case, it is not "the fifth taste", because there are not four tastes, or five, but undoubtedly an infinite number: there are sour, salty, bitter (detected by calcium fluorescence, see "Pots and Test Tubes", Pour la Science, Paris), sweet, but also many other tastes: that of glycyrrhizic acid from licorice, that of ethanol, etc.).

UNILATERAL (A L'):
(Dic ac fr) Cooking method which consists of cooking food on only one side (fish skin side down).