title: Effects of power ultrasound on oxidation and structure of beef proteins during curing processing.
abstract: The aim of this study was to evaluate the effects of power ultrasound intensity (PUS, 2.39, 6.23, 11.32 and 20.96Wcm(-2)) and treatment time (30, 60, 90 and 120min) on the oxidation and structure of beef proteins during the brining procedure with 6% NaCl concentration. The investigation was conducted with an ultrasonic generator with the frequency of 20kHz and fresh beef at 48h after slaughter. Analysis of TBARS (Thiobarbituric acid reactive substances) contents showed that PUS treatment significantly increased the extent of lipid oxidation compared to static brining (P<0.05). As indicators of protein oxidation, the carbonyl contents were significantly affected by PUS (P<0.05). SDS-PAGE analysis showed that PUS treatment increased protein aggregation through disulfide cross-linking, indicated by the decreasing content of total sulfhydryl groups which would contribute to protein oxidation. In addition, changes in protein structure after PUS treatment are suggested by the increases in free sulfhydryl residues and protein surface hydrophobicity. Fourier transformed infrared spectroscopy (FTIR) provided further information about the changes in protein secondary structures with increases in β-sheet and decreases in α-helix contents after PUS processing. These results indicate that PUS leads to changes in structures and oxidation of beef proteins caused by mechanical effects of cavitation and the resultant generation of free radicals.
authors.affiliation: Key Lab of Meat Processing and Quality Control, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China.
authors.forename: Da-Cheng
authors.initials: DC
authors.lastname: Kang
authors.affiliation: Key Lab of Meat Processing and Quality Control, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China.
authors.forename: Yun-He
authors.initials: YH
authors.lastname: Zou
authors.affiliation: Key Lab of Meat Processing and Quality Control, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China.
authors.forename: Yu-Ping
authors.initials: YP
authors.lastname: Cheng
authors.affiliation: Key Lab of Meat Processing and Quality Control, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China.
authors.forename: Lu-Juan
authors.initials: LJ
authors.lastname: Xing
authors.affiliation: Key Lab of Meat Processing and Quality Control, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China.
authors.forename: Guang-Hong
authors.initials: GH
authors.lastname: Zhou
authors.affiliation: Key Lab of Meat Processing and Quality Control, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China. Electronic address: wangang.zhang@njau.edu.cn.
authors.forename: Wan-Gang
authors.initials: WG
authors.lastname: Zhang
mesh_terms: D000818:Animals; D002417:Cattle; D008460:Meat; D010084:Oxidation-Reduction; D017433:Protein Structure, Secondary; D011506:Proteins / Q000737:chemistry*; D000069466:Red Meat; D017550:Spectroscopy, Fourier Transform Infrared; D014465:Ultrasonics
chemical_list: D011506:Proteins
keywords: FTIR; Power ultrasound; Protein oxidation; Protein secondary structure; Surface hydrophobicity