Effect of pasteurisation and high-pressure processing on selected bioactive components in human milk - An experimental study

High-pressure processing (HPP) represents a promising alternative to conventional Holder pasteurisation (HoP) used by human milk banks worldwide. The objective of this study was to identify whether the HPP would achieve the same or better retention of the content of selected analytes than the HoP. Samples collected from 15 breast milk donors were processed in four ways: i) no treatment; ii) HoP; iii) HPP in cycles (350 MPa, 4 cycles); iv) continuous HPP (350 MPa, 20 min). The content of secretory immunoglobulin A (sIgA), lactoferrin and lysozyme was determined using commercially available ELISA kits, and the lipase activity was assessed using an A-lipase activity assay kit. Data were compared statistically using paired t-tests. HoP significantly reduced the content of lysozyme and lactoferrin as well as lipase activity (P < 0.001). Cycled HPP significantly decreased lipase activity (P = 0.002), while continuous HPP led to a significant decrease in lysozyme content (P = 0.001) and lipase activity (P = 0.014). Cycled HPP showed high retention of pretreatment levels of lysozyme - median 99 (88; 99%), lactoferrin - 84 (66; 105%), and sIgA content - 83 (28; 117%). Among the studied treatment regimens, the best preservation of initial levels of bioactive components was achieved using HPP at 350 MPa in cycles.