Impact of refrigeration and freezing-thawing of breast milk on in vitro digestibility and liposoluble vitamin bioaccessibility in breast-fed infants

There is little information about the impact of refrigeration and freezing-thawing on breast milk digestibility under gastrointestinal conditions of healthy infants or those requiring pancreatic enzyme replacement therapy (PERT) such as infants with cystic fibrosis (CF). This study assessed the impact of refrigeration and freezing-thawing on fat and protein digestibility and liposoluble vitamin bioaccessibility of breast milk. In vitro digestion models mimicking both healthy infant and CF infant conditions were applied. Freezing-thawing significantly increased the fat globule particle size. For CF digestion, this change had a more negative impact when using a freezing-thawing process than when using refrigeration of breast milk, reducing lipolysis (up to 18%), proteolysis (up to 28%), and vitamin A and E bioaccessibility. Under healthy conditions, no significant effects were detected. An adequate pancreatic enzyme replacement therapy (PERT) dose (25 LU/mL of BM) would enable the same level of lipolysis (55%) as in the healthy scenario. In conclusion, breast milk is the only source of energy and nutrients for breast-fed infants, so to prevent the loss of nutrient absorption, those with CF should not be fed with frozen-thawed breast milk.