Differentiation of rye and wheat flour as well as mixtures by using the kinetics of Karl Fischer water titration.

The aim of this study was to find a simple way to differentiate between rye and wheat flour and their mixtures by using the kinetic parameters of Karl Fischer water titration (KFT). Consequently, the water content and type of molecules in rye and wheat mixtures used in Romanian bread making have been investigated by means of volumetric KFT. Further, the kinetics of KFT have been determined and novel kinetic parameters corresponding to "surface" and "strongly-retained" water molecules have been identified to discriminate between rye and wheat flour and their mixtures.

'Hidden parameters' of infrared drying for determining low water contents in instant powders.

Drying techniques are very frequently used and in many cases official methods for moisture determination. These methods, however, do not yield the water content as a result but a mass loss which is caused not only by the evaporation of water but by all substances volatile under the drying conditions, be they original components of the product or be they produced by decomposition reactions during the drying process. This mass loss varies therefore with the parameters applied like time, temperature, form of energy transfer, atmospheric pressure or surrounding humidity.

Determination of total polar parts with new methods for the quality survey of frying fats and oils.

During the frying process the fat undergoes several chemical and physical changes caused by heat, water and atmospheric oxygen. With prolonged heating time the accumulation of deterioration products leads to organoleptic failures and a decrease of the nutritive value. For the quality control of frying fats or oils the determination of total polar parts by preparative column chromatography is an approved standard method.

Water as a source of errors in reference materials.

In the field of reference materials, long-term stability is of highest importance. Particularly for biological matrices, any kind of deterioration must be avoided during shelf-life. In the production precautions are taken to prevent these, but possible alterations caused by intensive drying have been underestimated until today.

Investigations on the water content of candidate reference material CRM 679 cabbage powder.

The determination of the residual water content by thermal methods and especially by Karl Fischer titration in a candidate reference material of the European Commission (candidate CRM 679 cabbage powder) is described and discussed.

[Comparison of methods to characterise thermally altered frying fats and oils].

During the process of deep fat frying the fat or oil undergoes several chemical and physical changes. To guarantee an effective quality control for used frying fats simple and rapid methods for the measurement of heat abuse are needed. Therefore several frying oils were heated with and without foodstuff and the change of polar parts, acid number, colour acid number, specific absorption and dielectric properties with prolonged heating time were determined.