title: Total milk fat extraction and quantification of polar and neutral lipids of cow, goat, and ewe milk by using a pressurized liquid system and chromatographic techniques.
abstract: Although milk polar lipids such as phospholipids and sphingolipids located in the milk fat globule membrane constitute 0.1 to 1% of the total milk fat, those lipid fractions are gaining increasing interest because of their potential beneficial effects on human health and technological properties. In this context, the accurate quantification of the milk polar lipids is crucial for comparison of different milk species, products, or dairy treatments. Although the official International Organization for Standardization-International Dairy Federation method for milk lipid extraction gives satisfactory results for neutral lipids, it has important disadvantages in terms of polar lipid losses. Other methods using mixtures of solvents such as chloroform:methanol are highly efficient for extracting polar lipids but are also associated with low sample throughput, long time, and large solvent consumption. As an alternative, we have optimized the milk fat extraction yield by using a pressurized liquid extraction (PLE) method at different temperatures and times in comparison with those traditional lipid extraction procedures using 2:1 chloroform:methanol as a mixture of solvents. Comparison of classical extraction methods with the developed PLE procedure were carried out using raw whole milk from different species (cows, ewes, and goats) and considering fat yield, fatty acid methyl ester composition, triacylglyceride species, cholesterol content, and lipid class compositions, with special attention to polar lipids such as phospholipids and sphingolipids. The developed PLE procedure was validated for milk fat extraction and the results show that this method performs a complete or close to complete extraction of all lipid classes and in less time than the official and Folch methods. In conclusion, the PLE method optimized in this study could be an alternative to carry out milk fat extraction as a routine method.
authors.affiliation: Bioactivity and Food Analysis Department, Instituto de Investigación en Ciencias de la Alimentación, Consejo Superior de Investigaciones Científicas (CIAL-CSIC), C/Nicolás Cabrera 9, 28049 Madrid, Spain.
authors.forename: M P
authors.initials: MP
authors.lastname: Castro-Gómez
authors.affiliation: Bioactivity and Food Analysis Department, Instituto de Investigación en Ciencias de la Alimentación, Consejo Superior de Investigaciones Científicas (CIAL-CSIC), C/Nicolás Cabrera 9, 28049 Madrid, Spain.
authors.forename: L M
authors.initials: LM
authors.lastname: Rodriguez-Alcalá
authors.affiliation: Bioactivity and Food Analysis Department, Instituto de Investigación en Ciencias de la Alimentación, Consejo Superior de Investigaciones Científicas (CIAL-CSIC), C/Nicolás Cabrera 9, 28049 Madrid, Spain.
authors.forename: M V
authors.initials: MV
authors.lastname: Calvo
authors.affiliation: Laboratorio Interprofesional Lácteo de Castilla la Mancha, Avda. Portugal 42, 45600 Talavera de la Reina, Toledo, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Romero
authors.affiliation: Bioactivity and Food Analysis Department, Instituto de Investigación en Ciencias de la Alimentación, Consejo Superior de Investigaciones Científicas (CIAL-CSIC), C/Nicolás Cabrera 9, 28049 Madrid, Spain.
authors.forename: J A
authors.initials: JA
authors.lastname: Mendiola
authors.affiliation: Bioactivity and Food Analysis Department, Instituto de Investigación en Ciencias de la Alimentación, Consejo Superior de Investigaciones Científicas (CIAL-CSIC), C/Nicolás Cabrera 9, 28049 Madrid, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Ibañez
authors.affiliation: Bioactivity and Food Analysis Department, Instituto de Investigación en Ciencias de la Alimentación, Consejo Superior de Investigaciones Científicas (CIAL-CSIC), C/Nicolás Cabrera 9, 28049 Madrid, Spain. Electronic address: j.fontecha@csic.es.
authors.forename: J
authors.initials: J
authors.lastname: Fontecha
mesh_terms: D000818:Animals; D002417:Cattle; D002784:Cholesterol / Q000032:analysis; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005227:Fatty Acids / Q000032:analysis; D005260:Female; D006017:Glycolipids / Q000737:chemistry; D006023:Glycoproteins / Q000737:chemistry; D006041:Goats; D006801:Humans; D066292:Lipid Droplets; D008055:Lipids / Q000032:analysis* / Q000302:isolation & purification; D008892:Milk / Q000737:chemistry*; D010063:Ovum; D010743:Phospholipids / Q000032:analysis; D012756:Sheep; D013107:Sphingolipids / Q000032:analysis; D014280:Triglycerides / Q000032:analysis
chemical_list: D005227:Fatty Acids; D006017:Glycolipids; D006023:Glycoproteins; D008055:Lipids; D010743:Phospholipids; D013107:Sphingolipids; D014280:Triglycerides; C110367:milk fat globule; D002784:Cholesterol
keywords: fatty acid; milk lipid; phospholipid; pressurized liquid extraction