title: Effect of prolonged refrigeration on the lipid profile, lipase activity, and oxidative status of human milk.
abstract: OBJECTIVE
  The study was aimed at evaluating the effect of prolonged refrigeration of fresh human milk (HM) on its fatty acid profile, free fatty acid content, lipase activities, and oxidative status.
  
  
  METHODS
  HM from mothers of preterm newborns was collected, pooled, and placed in the neonatal intensive care unit (NICU) refrigerator. Pooled milk was aliquoted and analyzed within 3 hours of collection, and after 24, 48, 72, and 96 hours of storage. The milk samples were analyzed for pH, total and free fatty acid profile, lipase activity at room temperature and at 4°C, lipase activity at room temperature in presence of sodium cholate (bile salt-dependent lipase), total antioxidant capacity, thiobarbituric acid reactive species, malondialdehyde, and conjugated diene concentration. The experiment was replicated in 3 independent trials.
  
  
  RESULTS
  Prolonged refrigeration did not affect the fatty acid composition of breast milk, and preserved both its overall oxidative status and the activity of HM lipolytic enzymes. In particular, bile salt-dependent lipase activity, long-chain polyunsaturated fatty acids, and medium-chain saturated fatty acid concentrations were unaffected for up to 96 hours of refrigerated storage.
  
  
  CONCLUSIONS
  Prolonged refrigeration of fresh HM for 96 hours maintained its overall lipid composition. The limited lipolysis during storage should be ascribed to the activity of lipoprotein lipase, responsible for the decrease in pH. Our study demonstrates that infants who receive expressed milk stored for up to 96 hours receive essentially the same supply of fatty acids and active lipases as do infants fed directly at the breast.
authors.affiliation: Department of Pediatric and Adolescence Science, Neonatal Intensive Care Unit, University of Turin, Turin, Italy.
authors.forename: Enrico
authors.initials: E
authors.lastname: Bertino
authors.forename: Marzia
authors.initials: M
authors.lastname: Giribaldi
authors.forename: Cristina
authors.initials: C
authors.lastname: Baro
authors.forename: Valeria
authors.initials: V
authors.lastname: Giancotti
authors.forename: Marco
authors.initials: M
authors.lastname: Pazzi
authors.forename: Chiara
authors.initials: C
authors.lastname: Peila
authors.forename: Paola
authors.initials: P
authors.lastname: Tonetto
authors.forename: Sertac
authors.initials: S
authors.lastname: Arslanoglu
authors.forename: Guido E
authors.initials: GE
authors.lastname: Moro
authors.forename: Laura
authors.initials: L
authors.lastname: Cavallarin
authors.forename: Daniela
authors.initials: D
authors.lastname: Gastaldi
mesh_terms: D000975:Antioxidants / Q000032:analysis / Q000378:metabolism; D004041:Dietary Fats / Q000032:analysis* / Q000378:metabolism; D004795:Enzyme Stability; D005227:Fatty Acids / Q000032:analysis / Q000378:metabolism; D005230:Fatty Acids, Nonesterified / Q000032:analysis / Q000378:metabolism; D005260:Female; D061353:Food Storage; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007558:Italy; D008049:Lipase / Q000378:metabolism*; D015227:Lipid Peroxidation; D008054:Lipid Peroxides / Q000032:analysis / Q000378:metabolism; D008066:Lipolysis; D008071:Lipoprotein Lipase / Q000378:metabolism; D008315:Malondialdehyde / Q000032:analysis / Q000378:metabolism; D008895:Milk, Human / Q000737:chemistry* / Q000201:enzymology / Q000378:metabolism; D049590:Postpartum Period; D012034:Refrigeration; D013997:Time Factors
chemical_list: D000975:Antioxidants; D004041:Dietary Fats; D005227:Fatty Acids; D005230:Fatty Acids, Nonesterified; D008054:Lipid Peroxides; D008315:Malondialdehyde; D008049:Lipase; C548261:LPL protein, human; D008071:Lipoprotein Lipase