title: Drying and denaturation characteristics of α-lactalbumin, β-lactoglobulin, and bovine serum albumin in a convective drying process.
abstract: Drying and denaturation kinetics of aqueous droplets of α-lactalbumin (α-lac), β-lactoglobulin (β-lg), and bovine serum albumin (BSA) were measured in a convective drying environment. Single droplets having an initial droplet diameter of 2 ± 0.1 mm and containing 10% (w/v) protein concentration were dried using conditioned air (65 and 80 °C, 2-3% RH, 0.5 m/s velocity) for 600 s. The denaturation of these proteins was measured by using reversed-phase HPLC. At the end of 600 s of drying 13.3 and 19.4% α-lac was found to be lost due to denaturation at 65 and 80 °C, respectively. Up to 31.0% of β-lg was found to be denatured, whereas BSA was not found to be significantly (p > 0.05) denatured in these drying conditions. The formation and strength of skin and the associated morphological features were found to be linked with the degree of denaturation of these proteins. The secondary structure of these proteins was significantly (p < 0.05) affected and altered by the drying stresses. The β-sheet and random coil contents were increased in α-lac by 6.5 and 4.0%, respectively, whereas the α-helix and β-turn contents decreased by 5.5 and 5.0%, respectively. The β-sheet and random coil contents in β-lg were increased by 7.5 and 2.0%, respectively, whereas the α-helix and β-turn contents decreased by 3.5 and 6.0%, respectively. In the case of BSA the β-sheet, α-helix, and random coil contents were found to increase, whereas the β-turn content decreased.
authors.affiliation: School of Applied Sciences, RMIT University , Melbourne City Campus, Melbourne, VIC 3001, Australia.
authors.forename: M Amdadul
authors.initials: MA
authors.lastname: Haque
authors.forename: Peter
authors.initials: P
authors.lastname: Aldred
authors.forename: Jie
authors.initials: J
authors.lastname: Chen
authors.forename: Colin
authors.initials: C
authors.lastname: Barrow
authors.forename: Benu
authors.initials: B
authors.lastname: Adhikari
mesh_terms: D000818:Animals; D002417:Cattle; D003890:Desiccation; D006358:Hot Temperature; D007700:Kinetics; D007768:Lactalbumin / Q000737:chemistry*; D007782:Lactoglobulins / Q000737:chemistry*; D008894:Milk Proteins / Q000737:chemistry*; D011489:Protein Denaturation; D017433:Protein Structure, Secondary; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D000067816:Whey Proteins
chemical_list: D007782:Lactoglobulins; D008894:Milk Proteins; D000067816:Whey Proteins; D012710:Serum Albumin, Bovine; D007768:Lactalbumin