Evaluation of 5-hydroxymethylfurfural content in market milk products.

5-Hydroxymethylfurfural (5-HMF) is a cyclic aldehyde formed during non-enzymatic browning reactions. In milk, it is, on the one hand, a contaminant, on the other, a quality indicator. The objective of this study was to evaluate the content and selected factors affecting the concentration of 5-HMF in cows' milk and first infant milk. The content of 5-HMF in market milk varied widely, the average was 54.8 μg L-1 (3.3-136.8). There was no significant difference in the concentration of this contaminant between UHT, HTST pasteurised and micro-filtered milk. It was also shown that the content of lipid components did not affect the concentration and kinetics of the 5-HMF formation in milk subjected to thermal treatment. Lactose-free milk was characterised by a level of this compound much higher than regular products. The 5-HMF average contents in powder cows' milk and first infant milk were respectively 642 and 2315 μg kg-1.