The water content of foodstuffs affects the physical characteristics, technological processes, microbiological stability, and shelf life of foods, as well as having legal and economic ramifications
Determination of water content is one of the most frequent analyses performed on foodstuffs.
Water determination methods should not only be very accurate but also fast.
There are several methods for determining water in foods with Karl Fischer (KF) moisture analysis being the preferred method within the industry.
The nature and special characteristics of each sample, as well as the chemical state of the water in it, determine the appropriate method for the water measurement.
Bulk or free water is easy to determine using several methods.
Metrohm UK has sold many instruments to the food industry to do this analysis.
The Simplicity C instrument for low moisture determinations, typically in the range ppm to 0.1%, has been developed primarily aimed at unskilled operators, where a robust and simple to use instrument is of paramount importance.
This instrument analyses the sample quickly, reliably and without fuss.
The 870 Titrino plus is for high moisture contents, typically 0.1 - 100%.
Again, this too has been developed for simple use.
Metrohm understands that a robust instrument in demanding conditions is important to the customer.
With this in mind all Metrohm instruments are covered by a unique three year warranty.
On the other hand, the determination of tightly bound water is very difficult and can only be achieved using a limited number of methods.
Certain samples must first be pulverized before the determination to release the substances of interest.
One such method is by volumetric KF in conjunction with a high speed homogeniser.
High-frequency homogenisation is the only method that can guarantee that even plant samples are thoroughly homogenised.
In this method the cells are disrupted and the water present inside the cells is extracted.
Unfortunately, some substances dissolve only incompletely or too slowly in the KF working media.
In such cases sample preparation is crucial for obtaining correct and reproducible results.
However, up to now sample preparation was laborious and time-consuming.
With the new Titrando/homogeniser combination manual sample preparation can be dispensed with.
The high-frequency homogenizer from Metrohm is an adapted version of the Polytron homogeniser made by the Swiss company Kinematica.
This instrument effortlessly homogenises the sample without any other actions being required to form a thick paste.
The release of the water contained in the sample can be accelerated by adding a solubility promoter or by titration at a higher temperature (normally 50C).
Two high-frequency homogenisers with lengths of 115 and 154mm are available, allowing you to achieve the optimal result for your application.
As the comminution and homogenisation process takes place directly in the sealed titration vessel, any falsification of the analytical results can be ruled out.
No moisture can penetrate the sealed vessel from the atmosphere, and water released during the homogenization process cannot escape from the vessel.
