D-/L-Lactic acid, UV method

Enzymatic method for the determination of D- and L-lactic acids. Based on the spectrophotometric measurement of NADH formed through the combined action of D-lactate dehydrogenase (D-LDH) , L-lactate dehydrogenase (L-LDH) and D-alanine aminotransferase (D-ALT/D-GPT). This rapid and simple stereo-specific enzymatic method is used for the determination of D-(-)-lactic acid (D-(-)-lactate) and L-(+)-lactic acid (L-(+)-lactate) in foodstuffs such as milk and milk products (e. g. cheese, yogurt), wine, beer, dietetic food, fruit and vegetable products (e. g. juices, jam, tomato pulp), meat products, soft drinks and lemonades, vinegar, as well as in cosmetics, paper and cardboard, pharmaceuticals and biological samples. See also our test kits for D-lactic acid (cat. AK00121) and L-lactic acid (cat. AK00131). D-Lactic acid is a natural product formed only by lactic acid bacteria, such as Lactobacillus lactis, Lactobacillus bulgaricus and Leuconostoc cremoris. L-Lactic acid is a common final product of the metabolism of a wide variety of living organisms, including lactic acid bacteria. L-Lactate in wine is also formed during the malo-lactic fermentation ("second fermentation"). The production of D-lactic acid can indicate wine spoilage. The content of L-lactate in beer indicates the presence of Lactobacilli in production. Similarly, the quality of milk and fruit juice can be established by measurement of the D- and L-lactic acid content. L-Lactic acid is supplemented into foods and beverages (E270) where a tart flavour is desired, and is widely used as a non-volatile acidulant. The stereo-specific measurement of the lactate forms is of high interest e.g. in the manufacturing of sour milk products in order to assess the activity of microorganisms. The presence of D-lactic acid may indicate a microbial contamination. The content of L-lactate in liquid whole egg or in egg powder gives good information about the hygienic situation of the products. Components: * Solution 1 (assay buffer) * Solution 2 (NAD+ +PVP) * Suspension 3 (enzyme D-ALT) * Suspension 4D (enzyme D-LDH) * Suspension 4L (enzyme L-LDH) * Solution 5 (D-/L-Lactic acids standard solution * 0.15 mg of each/mL). Shipping Conditions: Room Temperature. Storage Conditions: 2 °C to 8 °C. Application: Biofuel, Dairy, Feed, Fermentation, Food, Wine. Features: Detection limit: 0.30 mg/L, Range: 0.30-300 mg/L. Detection Method: UV Method. Analyte: D-Lactic acid, L-Lactic acid