For quantitative determination of lactulose in food, beverage, agricultural products, and biological samples.

• Fast and sensitive, convenient
• Use of 40 μl sample
• Linear detection range 3 to 300 μM lactulose in 96-well plate assay
• High-throughput, "Add-mix-read" type assay
• Can be readily automated as a high-throughput 96-well plate assay for thousands of samples per day
• Method: OD565 nm
• Samples: Food, beverage, agricultural products and biological samples

The procedure involves adding a single working reagent, and reading the absorbance after 60 minutes. Room temperature assay. No 37 °C heater is needed. Lactulose (C₁₂H₂₂O₁₁) is a synthetic sugar that is non-digestible by the gut. It is used to treat constipation and hyperammonemia. It may also be used for intestinal permeability test for leaky gut. Lactulose can be found in milk-based products. Raw milk normally contains extremely low or no level of lactulose. However, the lactulose level in milk will increase after heat-treated.

Lactulose assay kit is based on β-galactosidase catalyzed oxidation of lactulose, which generates D-fructose and D-galactose. The generated D-fructose reacts with the specific reagent to form a colored product whose color intensity, measured at 565 nm, is proportional to the lactulose concentration in the sample.