title: Impact of ultrasound treatment on lipid oxidation of Cheddar cheese whey.
abstract: Ultrasound (US) has been suggested for many whey processing applications. This study examined the effects of ultrasound treatment on the oxidation of lipids in Cheddar cheese whey. Freshly pasteurized whey (0.86 L) was ultrasonicated in a contained environment at the same range of frequencies and energies for 10 and 30 min at 37°C. The US reactor used was characterized by measuring the generation of free radicals in deionized water at different frequencies (20-2000 kHz) and specific energies (8.0-390 kJ/kg). Polar lipid (PL), free and bound fatty acids and lipid oxidation derived compounds were identified and quantified before and after US processing using high performance liquid chromatography equipped with an evaporative light scattering detector (HPLC-ELSD), methylation followed by gas chromatography flame ionized detector (GC-FID) and solid phase micro-extraction gas chromatography mass spectrometry (SPME-GCMS), respectively. The highest concentration of hydroxyl radical formation in the sonicated whey was found between 400 and 1000 kHz. There were no changes in phospholipid composition after US processing at 20, 400, 1000 and 2000 kHz compared to non-sonicated samples. Lipid oxidation volatile compounds were detected in both non-sonicated and sonicated whey. Lipid oxidation was not promoted at any tested frequency or specific energy. Free fatty acid concentration was not affected by US treatment per se. Results revealed that US can be utilized in whey processing applications with no negative impact on whey lipid chemistry.
authors.affiliation: CSIRO Division of Animal, Food and Health Sciences, 671 Sneydes Road, Werribee, VIC 3030, Australia; Department of Agriculture and Food Systems, Melbourne School of Land and Environment, The University of Melbourne, Parkville, VIC 3010, Australia.
authors.forename: Amir Ehsan
authors.initials: AE
authors.lastname: Torkamani
authors.affiliation: CSIRO Division of Animal, Food and Health Sciences, 671 Sneydes Road, Werribee, VIC 3030, Australia. Electronic address: Pablo.Juliano@csiro.au.
authors.forename: Pablo
authors.initials: P
authors.lastname: Juliano
authors.affiliation: Department of Agriculture and Food Systems, Melbourne School of Land and Environment, The University of Melbourne, Parkville, VIC 3010, Australia.
authors.forename: Said
authors.initials: S
authors.lastname: Ajlouni
authors.affiliation: CSIRO Division of Animal, Food and Health Sciences, 671 Sneydes Road, Werribee, VIC 3030, Australia.
authors.forename: Tanoj Kumar
authors.initials: TK
authors.lastname: Singh
mesh_terms: D002611:Cheese; D005511:Food Handling / Q000379:methods*; D008055:Lipids / Q000737:chemistry*; D008894:Milk Proteins / Q000737:chemistry*; D010084:Oxidation-Reduction; D013010:Sonication; D000067816:Whey Proteins
chemical_list: D008055:Lipids; D008894:Milk Proteins; D000067816:Whey Proteins
keywords: Lipid oxidation; Phospholipids; Ultrasound; Whey