Transglutaminase-mediated glycation and crosslinking of β-lactoglobulin: Effect of amino-saccharides on rheological, thermal, and gelling properties

β-Lactoglobulin (β-Lg) was modified with glucosamine (GlcN) or chitosan oligosaccharide (COS) via transglutaminase catalysis to generate the glycated and crosslinked β-Lg (GC-β-Lg), which was investigated for possible property changes. Compared with β-Lg, GC-β-Lg showed more open and disordered secondary structure, enhanced thermal stability within 25–105 °C temperature range, increased particulate size, and higher apparent viscosity in water. Moreover, the used amino-saccharides affected GC-β-Lg's gelation, because COS and GlcN increased gel strength by 158–276 % and 642 %, respectively. Additionally, the gels from the GlcN-glycated β-Lg showed a denser micro-structural feature than those from the COS-glycated β-Lg. Interestingly, this used modification endowed GC-β-Lg with higher ability than β-Lg to form the heat-induced gels with better water holding capacity and less protein leachability. The results highlighted that this transglutaminase-mediated modification could alter β-Lg functionalities efficiently and could generate novel protein ingredients in the food industry, which was influenced by the used amino-saccharides.