Chemical Properties of L-Amino acids and 5-Nucleotides

1 (salt will be discussed separately). The commonly available naturally occurring flavor potentiators are either 5-carbon L-amino acids or purine ribonucleoside 5 -monophosphates having a 6-oxy group. 

It is of interest that flavor potentiating effect is very dependent upon structure of the molecule. For MSG, it is only the L form of the amino acid that has potentiating properties. The D form has no activity. Also, the ionic form is very important. The monosodium form (rather than diacidic or dibasic salt) is active while the other ionic forms have little activity. 

FIGURE 11.1 Structures of traditional flavor potentiators. (From Nagodawithana, T.W., Savory Flavors, Esteekay Assoe., Milwaukee, 1995. With permission.) 

In the case of the nucleotides, numerous isomers have been examined as possible flavor potentiators. Of the 2, 3, or 5 isomers, only the 5 -nucleotides have been shown to have potentiating activity [12,13]. With the 5 stracture, a hydroxy group in the 6 position is required to generate flavor potentiation. 

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