e-fructosyl-lysine (Furosine) test in milk

The chemical analysis of the milk and dairy products for quality control for every stage of the production chain with CDR FoodLabThe analisys of e-fructosil-lisine is an innovative method studied in CDR’s research laboratories to assess the effects of milk thermal treatments or or the addition of powder milk or UHT to crude or pasteurized milk that can be determined by using indicators like furosine and lactulose.

The laboratory of PARMALAT S.P.A. conduct a study realized the reliability and applicability of the test of ε-fructosil-lisine made by CDR concluding that the result are equivalent to those obtained through determination of furosine

Analyzers for determining ε-fructosyl-lisine (Furosine) in milk and dairy products


  CDR FoodLab for performing a range of tests in milk and a variety of dairy products CDR FOODLAB® CDR FoodLab for performing a range of tests in milk and a variety of dairy products CDR FOODLAB® JUNIOR
Analyses Milk and Dairy Products:
L-Lactic acid
Milk Urea Nitrogen (MUN)
Alkaline phosphatase (ALP)
Hydrogen peroxide
ε-fructosyl-lisine (Furosine)
Configuration with tailored panel of analyses
Simultaneous Sample Analyses 16 3
Multiple Analyses on a Sample si

It is not necessary skilled staff nor a laboratory for the analysis.
Results are correlated with reference method results.
It is free of service and maintenance cost.
With the same analyzers you can also perform analysis of egg, tomato, vegetable purees, cheeses and fats.


Test type: kinetic
Reading color a 545 nm
Time test: 6 minutes

Test principle

The effects of milk thermal treatments or the addition of powder milk or UHT to crude or pasteurized milk can be determined by using indicators like furosine and lactulose.

The determination of furosine enables to assess the intensity of the initial phase of Maillard’s reaction (that causes heated milk to develop a brownish color), which is in turn linked to milk thermal processes.

The e-fructosyl-lysine is the first stable product of Maillard’s reaction and can be converted into furosine by subjecting milk to an acid hydrolysis. Furosine is then analyzed with the HPLC method, which is rather long, complex and expensive. Thus the efructosyl-lysine, which is the first stable product of Maillard’s reaction and a precursor of furosine, can provide the same information resulting from the furosine test.

e-fructosyl-lysine + tetrazol salt frecciapurple complex

The test principle is based on a Redox reaction during which the tetrazol salt reacts with efructosyllysine forming a purple compound whose intensity, measured at 545 nm is directly proportional to the concentration of efructosyl-lysine

Calibration curve

Parmalat® and CDR have collaborated in a study on e-fructosyl-lysine to evaluate the possibility of using it as an index of thermal treatment in milk. Furosine and e -fructosyl-lysine tests were carried out in parallel on several types of milk samples. The correlation between the two tests (R=0.95) is good. These results indicate that ε-fructosyl-lysine and furosine values can be aligned.

The e fructose-lysine test has a good linearity (R2 = 0.99).

An internal CDR study on several types of milks enabled to determine the different classes of thermal treatments by using the e-fructosyl-lysine values. The e-fructosyl-lysine test, like the furosine test, enables to distinguish the main types of thermal treatments and between crude, pasteurized and UHT milk.

The discriminating limit values for the single classes shown in the table below are indicative. Users of the test should always define internal references to be able to assess the quality of the thermal treatment with a greater accuracy.

Type of milk ε-fructosyl-lysine
delta x 1000
Raw < 30
Pasteurized 30 – 80
UHT > 80

The linearity of the e-fructosyl-lysine test was also checked by adding incremental quantities of powder milk to whole pasteurized milk. As for furosine, the trend was linear (R furosine=0.997, R e-fructosyl-lysine=0.993) and sensitivity was good because the test was able to identify a 10% addition of powder milk in the pasteurized milk.

Diagram showing the variation of fructosyl-lisine and furosine checked by adding incremental quantities of powder milk to whole pasteurized milk

Reagent test Kits

The reagents are packaged in foil pouches containing 10 tubes useful to perform 10 analyses.

This is the minimum package that allows the use of CDR systems even to those who need to make a few analyses, thus not wasting reagents.

There are also boxes of 100 tests, however, packaged in 10 bags of 10 tubes containing the reagent.

Reagent test kit *300400, Suitable for 100 tests

Reagent test kit *300404, Suitable for 10 tests

The reagents have a shelf-life of 12 months.

Processing – Sample Volume – Measuring range

Use milk as is

  Measuring range Resolution Repeatability
e-fructosyl-lysine 10-1000 Delta X 1000 0,01 Delta X 1000 10 Delta X 1000
Furosine* 10-500 mg/100 g 0,1 mg/100 g 5 mg/100 g

Reagents developed by CDR S.r.l - Quality System Certified ISO 9001 Ed. 2015 - Certificate n. 9115

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With the CDR system, you can perform your tests in total autonomy

Neither skilled staff nor a dedicated external laboratory is needed to use our systems. CDR FoodLab® optimizes traditional testing methods, making them faster and easier, while guaranteeing accuracy standards in line with the reference methods.

Analytical kit

CDR FoodLab® Analysis Systems use disposable pre-vialed reagents specifically developed by the research laboratories of CDR. The use of pre-vialed reagents and the analytical procedures allow:

  • a sample preparation that is quick and easy, when needed at all;
  • making analytical procedures extremely fast and easy;
  • removing all needs for complex calibration procedures.

Reagents come in aluminum packages containing 10 test tubes each to perform 10 tests (or packages for 100 tests containing 10 single packages of 10 test tubes each).

Just a few steps and results are yielded right away

Just a few steps will suffice to carry out your analysis in a rapid way in total autonomy. The system is composed of both the analyzer based on photometric technology and a kit of low toxicity, pre-vialed reagents, developed by CDR.

CDR FoodLab® is cost-effective because it does not require the use of expensive equipment and does not entail maintenance, assistance or calibration costs.
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