Journal of Colloid and Interface Science, Vol.505, 736-744, 2017
Effect of crosslinking on the physical and chemical properties of beta-lactoglobulin (Blg) microgels
Hypothesis: Microgels assembled from the protein p-lactoglobulin are colloidal structures with potential applications in food materials. Modifying the internal crosslinking within these microgels using enzymatic or chemical treatments should affect dissolution, swelling, and viscous attributes under strongly solvating conditions. Experiments: Microgels were treated with citric acid, glutaraldehyde and transglutaminase to induce cross linking or with tris(2-carboxyethyl)phosphine to reduce disulfide linkages. Change in hydrodynamic particle size due to acidic pH, alkaline pH, ionic strength, osmolyte concentration, ethanol, urea, sodium dodecyl sulfate, and reducing agents was evaluated by light scattering measurements. Changes in microgel nanomechanical properties were evaluated via force spectroscopic measurements in water. Findings: Average microgel size increased similar to 20% in alkaline pH and with ethanol contents above 10%, and decreased. similar to 20% with sucrose contents above 10%. Cross-linking by glutaraldehyde and transglutaminase prevented size increases in alkaline pH. Microgel plasticity and elastic modulus were unaffected by treatments. Microgels treated with glutaraldehyde were found to have much greater stability to urea, sodium dodecyl sulfate, and reducing agents when compared to other samples. Even without cross-linking, microgels remained stable against precipitation and dissolution over a wide range conditions, indicating their broad utility as colloidal stabilizers, texture modifiers or controlled release agents in food or other applications. (C) 2017 Elsevier Inc. All rights reserved.
Keywords:beta-lactoglobulin;Microgel;Cross-linking;Citric acid;Glutaraldehyde;Transglutaminase;Denaturation