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Reinventing volumetric Karl Fischer titration: OMNIS KF!

Milk and dairy products

In compliance with international standards

Standards

The analysis of milk and dairy products requires error-prone and time-consuming sample preparation techniques. Our automated instruments take over sample preparation. Besides saving time and improving traceability, you can increase the reliability of your analyses and ensure compliance with international regulations.

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Sodium in dairy products

Determining salt (sodium ions) in cheese with thermometric titration

The sodium content of beverages is usually determined indirectly through a precipitation reaction with silver nitrate. This approach assumes that the chloride ions are present in a molar ratio of 1:1 with the sodium ions, which is not always the case. On the other hand, established methods for the direct determination of sodium such as AAS or ICP/MS are very expensive.

Thermometric titration is a cost-effective and straightforward alternative. First, proteins in the milk sample are precipitated with trichloroacetic acid and then separated through filtration or centrifugation. An aliquot is titrated in the presence of NH4F at a pH value of 3 with an aluminum nitrate solution with an excess of potassium ions. The exothermic reaction produces insoluble NaK2AlF6.

Check out the downloadable documents below to learn more about Na analysis in other foodstuffs.

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Laboratory automation in milk and dairy products

System for fully automated preparation of solid samples for titration applications

Analysis of milk and dairy products such as cheese and creams include, among others, the analysis of standard parameters such as pH value and acid content as well as the concentration of individual ions such as sodium, calcium, or chloride.

The presence of fats and proteins often renders sample preparation in milk and dairy products laborious and error-prone. Not so if you use the 815 Robotic Titration Soliprep with a Polytron homogenizer. The milk or dairy sample is simply weighed out and placed in the sample rack – everything else is fully automated. This guarantees identical sample preparation.

The possibilities to combine different working steps are almost unlimited; the instrument can be readily combined with a liquid chromatograph.

> Learn more about the 815 Robotic Titration Soliprep

Ion chromatography – A versatile method for dairy products

With its different separation mechanisms, detection types, as well as automation and sample preparation possibilities, ion chromatography (IC) is highly versatile and also covers the determination of carbohydrates, organic acids, chloride and sulfate, alkali metals and alkaline earth metals as well as antioxidants.

Ions in UHT milk

Chromatogram of chloride, phosphate, and sulfate in processed milk

For dairy products – be it baby food, yoghurt, milk, or lactose-free foods – ion analysis is essential to quality control. Many of the inorganic elements found in milk can be determined by ion chromatography. It permits the determination of

  • anions (e.g., iodide, chloride, phosphate, sulfate, nitrate, nitrite, thiocyanate, cyanurate, and perchlorate),
  • cations (e.g., sodium, ammonium, potassium, calcium, magnesium, and melamine),
  • and carbohydrates (e.g., galactose and lactose).

Inline Dialysis is an efficient sample preparation technique for fully automatic removal of protein-containing matrices.

Hence, dialysis eliminates the tedium of the manually performed protein precipitation step with Carrez reagent.

Lactose in "lactose-free" products

Dairy products

Lactose is the main sugar in milk, which is why it is also present in most dairy products. Lactose is a remarkable source of energy. In the gastrointestinal tract, lactase enzymes break down the lactose into the subunits glucose and galactose. Many people lack the lactase enzyme and therefore cannot digest lactose.

To avoid symptoms, the people affected may consume lactose-free products. Lactose-free usually is understood as less than 100 mg lactose per kg product. Lactose-free milk is analyzed applying Inline Dialysis before sample injection.

Iodide, thiocyanate, and perchlorate in milk using Inline Dialysis

Analysis of milk and dairy products

As mentioned above, ion analysis in milk requires sophisticated sample preparation to avoid column fouling by fats or proteins. Again, Metrohm Inline Dialysis is the perfect automated sample preparation technique.

With IC, all three ions – iodide, thiocyanate, and perchlorate – can be easily determined in a single run, even in milk matrices.

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Webinar

Screenshot webinar Ion chromatography for food analysis_precise, safe, and economical

Ion Chromatography for Food Analysis: Precise, Safe, and Economical 

This webinar focuses on applications for food safety in milk products, for quality control issues in meat and fish, and for the monitoring of health-hazardous ions in soft drinks and bakery products.

We show ways to reduce costs and time of your analysis and improve robustness and reliability of your results. You will also learn how to improve efficiency using automated sample preparation (e.g., inline ultrafiltration, inline dialysis, inline dilution).

> Watch the webinar

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8/16/2019

How online chemical analysis can help maximize efficiency of chlor-alkali production

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