High temperature induced structural changes of apo-lactoferrin and interactions with β-lactoglobulin and α-lactalbumin for potential encapsulation strategies

There has been increasing interest in lactoferrin as a bioactive compound from milk, as it functions as an antimicrobial and also in delivering iron. Despite the potential as a food ingredient, the low bioavailability of lactoferrin has limited opportunities for commercialisation. Therefore, protective encapsulation of lactoferrin has been explored as a means of enhancing its bioavailability. In this study, a novel in silico approach was adopted to explore the possibility of employing whey protein components to encapsulate lactoferrin. The most unstable form of the protein, apo-lactoferrin has been studied, particularly interactions with the whey proteins beta-lactoglobulin and alpha-lactalbumin. Temperature conditions that might be encountered during spray drying (95 and 180 degrees C) have been modelled in order to provide an in-depth understanding of the interactions at the molecular level. The findings indicate that beta-lactoglobulin and alpha-lactalbumin are able to preserve the two antibacterial regions within the apo-lactoferrin structure (lactoferricin and lactoferampin). Intra-molecular residue contact analyses within apo-lactoferrin illustrate the tendency for agglomeration under these temperature conditions, indicating that it is most likely to be readily dispersible during subsequent rehydration. Furthermore, free energy calculations found electrostatic attractions to be the primary mode of interaction between apo-lactoferrin, beta-lactoglobulin, and alpha-lactalbumin. This data is confirmed by a network analysis that demonstrates how interactions amongst apolactoferrin, beta-lactoglobulin, and alpha-lactalbumin are predominantly a result of the acidic and basic amino acid residues of the proteins. Overall, this study provides molecular insights in understanding the interactions between lactoferrin with beta-lactoglobulin and alpha-lactalbumin for potential encapsulation strategies via spray drying.