Maillard reaction induced lactose attachment to bovine beta-lactoglobulin: electrospray ionization and matrix-assisted laser desorption/ionization examination

Nonenzymatic attachment of lactose to beta-lactoglobulin (beta-Lg) was investigated under different conditions. Solubilized conditions, dry environment, and a combination of dry and solubilized environments, were examined for their effects on lactosylation. Temperatures ranging from 50 to 65 degrees C and time intervals between 1 h and 4 days were used. Electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI) mass spectrometry were implemented to examine the reaction products. Maximum attachment efficiency occurred at 65 degrees C held for 3 h in dry-way conditions. Incubations held for long periods of time under dry-way conditions suggest possible denaturation. Both ESI and MALDI data suggest beta-Lg removal in the solubilized samples held for long periods of time. A combination of solubilized and dry environments led to very similar mass spectrogram results over time.