Assessment of heat treatment of milk: a proposal for a new index using UV-derivative spectroscopy
1996
Luf, W. (Vienna Veterinary Univ. (Austria). Inst. of Milk Hygiene and Milk Technology)
Derivative spectroscopy in UV enables detection of the whey protein fraction mixed with casein. Different contents of aromatic amino acids are the basis of such determinations. Methods for distinguishing milk powders as well as market milks according to their heat load have been published using this detection principle. These methods require calibration using appropriate whey protein and casein standards. A new approach is now proposed, using the ratio between derivative bands of whey and the corresponding milk described as Q279 and Q286 belonging to the two characteristic wavelengths. The advantage of such parameters is the independence of the spectrophotometer used, because the specific apparatus-induced deviations are cancelled. A relation between these Q-values and the heat load expressed as temperature and time as well as other indices is presented.
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