Shikimic acid VOLUME

Figure 1.7 HPLC chromatogram of organic acids analysis of Prosecco grape must sample. 1. tartaric acid, 2. malic acid, 3. citric acid, 4. shikimic acid. Analytical conditions Lichrospher 100 RP-18 (250 x4mm, 5p,m) column (Merck, Darmstadt, Germany) at room temperature, detection at wavelength 210 nm, sample volume injected 20/xL solvent H3P04 5 x 10 3 M with isocratic elution at flow rate 0.6 mL/min...

Figure 1.12 Chromatogram relative to analysis of organic acids in a Pinot blanc wine sample. 1. citric acid, 2. tartaric acid, 3. malic acid, 4. pyruvic acid, 5. succinic acid, 6. shikimic acid, 7. lactic acid, 8. acetic acid. Analytical conditions column Aminex HPX-87H (300 x 7.8mm, 9p.m) at 65 °C (Bio-Rad Laboratories, Richmond, CA) detection at wavelength 210nm sample volume injected 10gL solvent H2S04 0.02N/acetonitrile (91.5 8.5 v/v) with isocratic elution at flow rate 0.6mL/min...

Most of the acids of the metabolism are found in trace amounts in ripe grape pulp (pyruvic, a-ketoglutaric, fumaric, galacturonic, shikimic, etc.). Must acidity, an important element of enological data, is essentially constituted by three acids tartaric, malic and citric acid (Volume 2, Section 1.2.2). It can vary from 3 to 10 g/1 in sulfuric acid or from 4.5 to 15 g/1 in tartaric acid, depending on the cultivar, the climate and grape maturity. Phosphoric acid is the preponderant inorganic anion. 

Although shikimic acid and quinic acid are certainly not large-volume chemicals, these hydroaromatics provide an intriguing entry point into large-volume fine chemicals and pseudocommodity chemi-... 

Much attention has been given to other enzymes of phenolic biosynthesis, and a veritable spate of papers, many of purely physiological interest, has appeared on the topic of phenylalanine ammonia lyase. Full details of the work on the stereochemistry of this enzyme have been published during the year. A paper on the biosynthesis of aromatic amino-acids from shikimate is of general significance, since it indicates that m-carboxy-substituted aromatic acids can be formed without involving prephenic acid as an intermediate. These results are discussed in more detail elsewhere in this volume (see Chapter 3). 

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