Does lactoferrin, free, encapsulated or in dairy matrices, maintain its antibacterial activity after in vitro digestion?

Milk is a source of active compounds with defensive properties, such as lactoferrin and milk fat globule membrane proteins. These proteins generate bioactive peptides in the gastrointestinal tract and it is known that industrial processing can modify their susceptibility to digestion. However, does lactoferrin maintain its antibacterial activity after passing through the gastrointestinal tract? The aim of this study was to evaluate the effect of technological treatments, encapsulation and in vitro digestion on lactoferrin antibacterial activity against Listeria monocytogenes. The results showed that the gastric digest of free lactoferrin presented greater effect against L. monocytogenes than the intestinal digest; although less than undigested lactoferrin. Alginate-lactoferrin microbeads allowed the release of lactoferrin into the intestine, protecting it from pepsin, although it was not sufficient to maintain its antibacterial activity to the intestine. However, homogenization and pasteurization favoured the antibacterial activity of dairy formulas supplemented with lactoferrin and of their digests.