The use of steam distillation as a separation process is a proven and cost-effective method utilised in many areas of food production, animal feed manufacture and environmental analysis
Nitrogen and protein determinations in accordance with Kjeldahl, the Devarda method, eg, for fertilizers, the determination of steam-volatile compounds such as alcohol, phenols or SO2 - this technique represents a key step in sample preparation.
Buchi Labortechnik, a supplier of systems for determining protein and fat, has published several new application notes that show how Kjeldahl systems can be used for much more than traditional protein determination in the field of food analysis.
The application notes explain step by step how the alcohol content of wines and spirits or the fraction of volatile acids is determined in compliance with official standards such as EEC 2870/2000 or EEC 2676/90.
TVB-N (total volatile basic nitrogen) is another interesting example.
TVB-N is responsible for the sometimes-unpleasant smell of fish and consists of volatile nitrogen compounds.
The application illustrates the use of Buchi Distillation Unit K-355 for determining TVB-N in fish and fish products in accordance with EU Directive 95/149/EC.
A new EU Directive, 2003/89/EG, prescribes the declaration of substances that trigger allergic reactions contained in foods and alcoholic drinks.
The new labelling requirement covers twelve groups of substances including sulphur dioxide in a concentration of more than 10mg/kg or 10mg/l, measured in terms of SO2.
Buchi application note K355-002 shows two examples of SO2 determination in beverages an dried fruit.
