Milk and dairy products

Lactose is a reducing sugar, which is present in milk in concentrations ranging from 4.5 to 5 g/100 gr. The lactose molecule is a disaccharide composed of one glucose and one galactose sub-units, and is indispensable for many fermentation processes that take place within milk. The reduced secretion of the lactase enzyme in human beings is associated with an intolerance to lactose, and, accordingly, to milk and its derivative products.The test is suitable for use on lactose free products, where a part or all the lactose has been broken down to glucose and galactose by the lactase enzyme, it is also suitable for products where lactose is normally present.

Chemical test for lactose in milk and dairy products

CDR FoodLab® is the chemical analyzer for quality and process control that allows you to determine a wide range of parameters of many foods, animal feeds and pet foods. 

Method

Endpoint analysis. Analysis time: [uni]. Analysis sessions with multiple samples are possible up to a maximum of 16 tests for CDR FoodLab® and 3 tests for CDR FoodLab® Junior.&nbsp;<h3>Sample treatment</h3>Milk: Dilute 1 part of milk + 10 parts of water. E. g. take 100 uL of milk and add it to 1mL of distilled water. It's possible to use the appropriate dilution kit. Cheese, yogurt, cream, margarine and butter: weigh 10 grams of sample and add 100 mL of distilled water. Mix in a Stomacher for about 3 minutes. Use the diluted solution thus obtained for analysis.

Lactose is split in glucose and galactose. Glucose reacts with a phenolic compound through an enzymatic reaction, with peroxidase, and forms a pink coloured complex. The absorbance of the complex is read at 505 nm, and the value is directly proportional to the concentration of lactose in the sample.

Test principle

The accuracy of the CDR FoodLab® method was evaluated by determining the correlation between the results of different milk samples, obtained by analysis with CDR FoodLab® and those obtained by the Istituto Zooprofilattico by means of the HPLC method (High Performance Liquid Chromatography) as foreseen by the method of reference MP 02/050 rev.6- 2018. [<a href="/cdrfoodlab/validations/analysis-lactose-milk-correlation-cdrfoodlab-reference-method">Take a look at the complete study</a>]

Correlation curve

Correlation between the data obtained from the laboratory of the zooprophylactic institute and those of CDR FoodLab®. R²=0.9903

The Poligny ACTALIA (France) reference laboratory, specialising in food analysis, performed an evaluation study: the <a href="/cdrfoodlab/validations/actalia-cdrfoodlab-evaluation-milk#lattosio">analysis of lactose on lactose-free milk was performed with CDR FoodLab® and with the HPLC method (ISO 22662)</a> . The correlation R2&nbsp;= 0.9882 is excellent considering the type of analysis and the difficulty in performing the reference methods.

Correlation chart Analysis of lactose on CDR FoodLab® delactosed milk and HPLC method (ISO 22662). Correlation R² = 0.9882

Reagent test Kits

Measuring range

CDR FoodLab® the analyzer for quality control of food, animal feeds and pet foods. Top version

CDR FoodLab®

CDR FoodLab® the analyzer for quality control of food, animal feeds and pet foods. Junior version