Hydrogel formation from peptides of a B-lactoglobulin tryptic hydrolysate: Contribution of self-assembling peptide B-Lg f1-8

Peptide-based hydrogels, typically mediated by non-covalent interactions, are becoming increasingly attractive due to their many biotechnological applications such as drug and antimicrobial delivery, as well as tissue en-gineering. In our previous work, we demonstrated that specific peptide fractions from beta-lactoglobulin (B-Lg) could form hydrogels either by peptide-peptide interaction or through peptide self-assembly of B-Lg f1-8, depending on the purity of B-Lg f1-8 in peptide fractions. However, mechanisms that govern hydrogel forma-tion were not investigated. Consequently, this study focused on the impact of peptide fraction (pellet) concen-tration, temperature, pH and B-Lg f1-8 concentration on hydrogel formation. Moreover, contribution of peptides B-Lg f15-20 and B-Lg f41-60 to hydrogel formation was determined. We hypothesized that hydrogel formation results from a balance between hydrogen, hydrophobic and electrostatic interactions during gelation at a con-centration of 50 mg/mL, 20 degrees C and pH close to 11. The peptide B-Lg f1-8 was shown to initiate the gelation by increasing the density of nanofibers in a concentration-dependent manner which promoted peptide-peptide in-teractions. Finally, interactions between both B-Lg f15-20 and B-Lg f41-60 peptides and B-Lg f1-8 occurred during gel formation negatively impacted the self-assembly process. The proposed mechanism for B-Lg f1-8 gelation would facilitate the development of functional soft biomaterials and bioactive encapsulation systems.