The formation mechanism of β-lactoglobulin self-assembled gel and its relationship with slow-release properties through stepwise regression models

In our previous study, fibrous and granular whey protein self-assembled gels with low gel critical concentration (6%, w/w) and high gel mechanical strength were prepared, which showed good encapsulation and slow-release properties for epigallocatechin gallate. In order to better understand the gel formation mechanism, this study investigated the correlation between the gel quality and the protein structure based on kinetic pathways for fibrous (FBSG) and worm-like (WBSG) β-lactoglobulin self-assembled gels. The unheated samples of both FBSG and WBSG exhibited a loose structure, with the lowest hardness (6.733 g and 7.231 g, respectively) and rheological properties (G′ of 243 Pa and 79.9 Pa, respectively). As the heating time increased, the structures of FBSG and WBSG became denser, the hardness was increased and the rheological properties was improved. Hydrogen bonds and hydrophobic interactions played key roles in the formation of both FBSG and WBSG. Heat treatment had a greater influence on the formation of disulfide bonds in WBSG. In addition, we modelled and predicted about the gel delivery and slow-release properties using stepwise regression. The results showed that the three models about WBSG could be used for subsequent prediction, with adjusted R 2 of 0.989, 0.989, and 0.981, respectively, which was a good fit; the average absolute errors (measured and predicted) of the models regarding the encapsulation efficiency, loading capacity and gastric release rate of WBSG were −0.12%, −0.0061 μg/mg and −0.553%, respectively, with good model predictions. These findings provide valuable insights for the production and application of functional and special medical foods.