Enzymatic method for L-malic acid determination
- Kit volume: 100 ml
- Method: Two-reagent differential at 340 nm
- Limit of linearity: 4 g/l
- Limit of detection: 16 mg/l (ppm)
Advantages
- Stable liquid reagent until the expiration date
- Ready-to-use dedicated reagent
- Stable working reagent for 4 months
- Liquid calibrator included in the kit
L-malic acid is responsible for the sharply acidic, green apple flavor in wine. It’s fermentation yields L-lactic acid and causes perceived acidity to soften.
L-malic acid in the sample yields NADH (by the following reaction), which can be measured by spectrophotometry. The equilibrium of this reaction moves toward L-malic acid formation. The enzyme glutamate-oxaloacetate transaminase (GOT) causes the equilibrium to shift by eliminating oxaloacetate, which is converted into L-aspartate in the presence of L-glutamate.
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