Stability and functionality of bovine lactoferrin powder after 9 years of storage

Bovine lactoferrin (bLF) is a multifunctional protein widely used in food industries. Most bLF products are delivered in a powder form; however, their stability remains unclear. Herein, freeze-dried bLF powders were stored at 4 °C and 40 % relative humidity (RH) for 9 years since 2016. After the long-term storage, their functional properties, including antibacterial ability, antioxidant ability and iron-binding ability, were determined and compared with those of eight commercial LF powders. The bLF powder stored for 9 years demonstrated comparable physicochemical and functional properties with those of commercial LF powders (e.g. >93 % water solubility, >100 mg/100 g iron-binding ability, and >1.7 logCFU/mL bacterial growth reduction against <i>Salmonella enteritidis</i>). The haemolysis test indicated that the bLF stored for 9 years exhibited good biocompatibility at a concentration of <5 mg/mL. Therefore, bLF powders can be stored for extremely long periods (>9 years) with minimal side effects. These findings can expand the utilisation of lactoferrin to many specific cases such as voyage and aerospace foods.