Modification of whey protein microgel particles with mono- oligo- and polysaccharides through the Maillard reaction: Effects on structural and techno-functional properties

Abstract

Many food and drink products have a pH value between 4.0 and 6.0, which is near the isoelectric point (pI) of whey proteins. This study evaluated the modification of whey protein microgel (WPM) through Maillard conjugation with several common saccharides including arabinose, glucose, fructose, lactose, inulin, and maltodextrin in a liquid system, which is considered a potential route to boost the utilization of these protein particles in acidic conditions. Glycation degree (22–31 %), pH decrease, presence of final products, FTIR, and SDS-PAGE confirmed the bonding of carbohydrates to WPMs. The conjugates prepared by lactose, glucose, and inulin, i.e. moderately reactive carbohydrates, rendered lower surface hydrophobicity, higher colloidal stability (∼40−50% at pH 4.0), and improved emulsifying properties in comparison with WPM, heated WPM and other glycoproteins. Foaming capacity of Maillard reaction products was lower or without change relative to the WPM; however, foam prepared by maltodextrin-glycated WPM was substantially more stable (up to 24 h). These findings could open avenues for applicability of these pre-denatured densely-packed particles in a range of food products and soft-matter applications.