D-Malic Acid, UV method

Enzymatic method for the determination of D-malic acid. Based on the spectrophotometric measurement of NADH formed through the action of D-malate dehydrogenase (D-LDH). This rapid and simple stereo-specific enzymatic method is used for the determination of D-malic acid (D-malate) in foodstuffs such as wine, fruit and vegetable products, as well as in pharmaceuticals and biological samples. D-Malic acid practically does not occur in nature, it is a metabolite produced only by some microorganisms. Analysis of freshly pressed fruit juices shows the presence of D-malic acid at the detection limit. Hence, the D-Malic legal limit for fruit and fruit juices is recommended as 10 mg/L. D-Malic acid is a component of the (racemic) D-/L-malic acid as prepared chemically. Since natural products are practically free of D-malic acid, the detection of Dmalic acid could indicate that D-/L-malic acid has been added e.g. to wine or to fruit juice. This may be allowed or forbidden and thus the legal situation in the different countries has to be taken into consideration. Components: * Solution 1 (assay buffer) * Solution 2 (cofactor NAD+) * Suspension 3 (enzyme D-MDH) * Solution 4 (D-Malic acid standard solution * 0.20 mg/mL). Shipping Conditions: Room Temperature. Storage Conditions: 2 °C to 8 °C. Application: Food, Wine. Features: Detection limit: 0.26 mg/L, Range: 0.25-400 mg/L. Detection Method: UV Method. Analyte: D-Malic acid