Characteristics and antioxidant activity of hydrolyzed β-lactoglobulin-glucose Maillard reaction products

Maillard reaction products (MRPs) were prepared by reacting hydrolyzed beta-lactoglobulin (LH) with glucose (Glu) at 90 degrees C for up to 18 h of heating. Solutions of LH and glucose were also heated alone as controls. The chemical properties of MRPs (heated LH-glucose) and their antioxidant activity were investigated. Besides the Maillard reaction, the browning intensity and absorbance at 294 nm of heated LH-glucose was partially due to the caramelisation reaction of glucose. Fluorescence intensity of heated LH-glucose were mainly associated with the Maillard reaction. Heated LH-glucose increased DPPH radical scavenging activity, reducing power and iron chelating activity, which was partially related to the caramelization of glucose. Both the 2 h and 4 h heated LH-glucose showed the strongest antioxidative activity in fish oil-in-water emulsions, and longer heating times (>4 h) decreased their ability to inhibit lipid oxidation, but it was not related to the caramelization of glucose. Therefore, Mallaird reaction was a potential method to improve the antioxidant activity of hydrolyzed beta-lactoglobulin. (C) 2011 Elsevier Ltd. All rights reserved.