title: Reduced functionality of PSE-like chicken breast meat batter resulting from alterations in protein conformation.
abstract: The objectives of this study were to evaluate protein thermal stability, water-protein interaction, microstructure, and protein conformation between PSE-like and normal chicken breast meat batters. Sixty pale, soft, and exudative (PSE)-like (L*>53, pH24 h<5.7) and 60 normal (46<L*<53, 5.7<pH24 h<6.1) chicken breast meats were selected from 3 different occasions in a major Chinese commercial plant. Two different meat batters were formulated to 14% meat protein and 2% salt, and they were analyzed for the protein changes and the microstructure using differential scanning calorimetry, low-field (LF)-NMR, SEM, and Raman spectroscopy. PSE-like meat batter had lower gel strength, water-holding capacity, and salt-soluble protein extraction (P<0.05). Heated PSE-like meat batter formed an aggregated gel matrix, while normal meat batter produced a compact gel network with fine, cross-linked strands by many protein filaments. LF-NMR revealed an increase in the water mobility in heated PSE-like meat batter with an increasing amount of loosely bound water (P<0.05). No significant changes were observed in the electrophoretic patterns of salt-soluble protein extracts by SDS-PAGE. However, differential scanning calorimetry showed that PSE-like meat had greater myosin and sarcoplasmic proteins/collagen denaturation (P<0.05). In PSE-like meat, actin denaturation was particular evident after salt addition (P<0.05) using differential scanning calorimetry. Moreover, Raman spectroscopy indicated that PSE-like meat batter had less unfolded α-helix and β-sheet structure formation, reduced exposure of hydrophobic and tyrosine residues (P<0.05), and changes in the microenvironment of aliphatic residues and tryptophan, which affected salt-soluble protein extraction, gel properties, and water-holding capacity. In conclusion, the inferior functional properties of PSE-like meat were attributed to not only myosin denaturation, but also actin denaturation after salt addition and different protein structural states.
authors.affiliation: Key Laboratory of Meat Processing and Quality Control, Ministry of Education, Key Laboratory of Animal Products Processing, Ministry of Agriculture, Synergetic Innovation Center of Food Safety and Nutrition, College of Food Science and Technology, Nanjing Agricultural University, Nanjing, 210095, PR China.
authors.forename: K
authors.initials: K
authors.lastname: Li
authors.affiliation: Key Laboratory of Meat Processing and Quality Control, Ministry of Education, Key Laboratory of Animal Products Processing, Ministry of Agriculture, Synergetic Innovation Center of Food Safety and Nutrition, College of Food Science and Technology, Nanjing Agricultural University, Nanjing, 210095, PR China.
authors.forename: Y Y
authors.initials: YY
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Meat Processing and Quality Control, Ministry of Education, Key Laboratory of Animal Products Processing, Ministry of Agriculture, Synergetic Innovation Center of Food Safety and Nutrition, College of Food Science and Technology, Nanjing Agricultural University, Nanjing, 210095, PR China.
authors.forename: Z L
authors.initials: ZL
authors.lastname: Kang
authors.affiliation: Key Laboratory of Meat Processing and Quality Control, Ministry of Education, Key Laboratory of Animal Products Processing, Ministry of Agriculture, Synergetic Innovation Center of Food Safety and Nutrition, College of Food Science and Technology, Nanjing Agricultural University, Nanjing, 210095, PR China.
authors.forename: P
authors.initials: P
authors.lastname: Wang
authors.affiliation: Key Laboratory of Meat Processing and Quality Control, Ministry of Education, Key Laboratory of Animal Products Processing, Ministry of Agriculture, Synergetic Innovation Center of Food Safety and Nutrition, College of Food Science and Technology, Nanjing Agricultural University, Nanjing, 210095, PR China.
authors.forename: M Y
authors.initials: MY
authors.lastname: Han
authors.affiliation: Key Laboratory of Meat Processing and Quality Control, Ministry of Education, Key Laboratory of Animal Products Processing, Ministry of Agriculture, Synergetic Innovation Center of Food Safety and Nutrition, College of Food Science and Technology, Nanjing Agricultural University, Nanjing, 210095, PR China xlxu@njau.edu.cn.
authors.forename: X L
authors.initials: XL
authors.lastname: Xu
authors.affiliation: Key Laboratory of Meat Processing and Quality Control, Ministry of Education, Key Laboratory of Animal Products Processing, Ministry of Agriculture, Synergetic Innovation Center of Food Safety and Nutrition, College of Food Science and Technology, Nanjing Agricultural University, Nanjing, 210095, PR China.
authors.forename: G H
authors.initials: GH
authors.lastname: Zhou
mesh_terms: D000818:Animals; D002645:Chickens / Q000502:physiology; D004591:Electrophoresis, Polyacrylamide Gel; D005511:Food Handling; D006358:Hot Temperature; D008460:Meat / Q000032:analysis*; D010369:Pectoralis Muscles / Q000502:physiology*; D011487:Protein Conformation; D011489:Protein Denaturation
keywords: LF-NMR; PSE-like; Raman spectroscopy; chicken; protein conformation