High-performance liquid chromatographic determination of furfural compounds in infant formulas during full shelf-life

In order to evaluate the extent of the Maillard reaction in adapted and follow-up infant formulas (IF), a study was made of the evolution of furfural compound (2-furaldehyde, 5-hydroxymethyl-2-furfuraldehyde, 2-furylmethylketone and 5-methyl-2-furaldehyde) in these products, along with their relation to available lysine during the shelf-life period (two years at 20 and 37 degreesC). Total and free furfural contents were measured by RP-HPLC and UV detection, heating or not the sample in boiling water to free the furfurals bound to proteins and the furfurals formed from precursors. Only 2-furylmethylketone and 5-hydroxymethyl-2-furfuraldehyde were detected. Adapted and follow-up IF showed similar behaviour during shelf-life, with a significant increase in furfural compound contents at the end of the storage period that was more marked at 37 degreesC than at 20 degreesC. In both IF, a correlation was obtained between furfural contents and the cubic time variable, which explains the irregular increase of these compounds over time, and between available lysine and furfural compounds in the second storage year - indicating the Maillard reaction to be in an advanced stage. Results obtained indicate that under storage conditions furfural content is a useful indicator of advanced Maillard reaction stages. (C) 2004 Elsevier Ltd. All rights reserved.