title: Effect of fast pH decline during the early postmortem period on calpain activity and cytoskeletal protein degradation of broiler M. pectoralis major.
abstract: The objective of this study was to determine the effects of fast pH decline during the early postmortem period on calpain activity and the degradation of cytoskeletal proteins in broilers. Eighty broilers were randomly categorized into two groups: physical restraint (PR) and free struggle (FS). M. pectoralis major (PM) was used for determination of calpain activity, shear value, ultrastructure of myofibrils, and the degradation of desmin, titin, nebulin, and troponin-T. The pH (6.05) of FS group is significantly low than PR group (6.38) at 0.3 h postmortem. Fast pH decline during the early postmortem period led to a decrease of μ/m-calpain activities at 0.3 and 3 h postmortem (P < 0.05), but did not affect the ultimate μ/m-calpain activity. An initial fast decrease in pH increased the degradation of desmin, titin, nebulin, and increased the 30 kDa degradation fragments of troponin-T. Therefore, the fast pH decline during the early postmortem period decreased the μ/m-calpain activity and increased the degradation of cytoskeletal proteins in broiler muscle. It is possible that the fast pH decline experienced an earlier activation of calpains that resulted in earlier protein degradation and ultimately lower shear force.
authors.affiliation: Department of Engineering, Nanjing Agricultural University, Nanjing 210095, China Key Laboratory of Meat Processing and Quality Control, Ministry of Education China, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: J C
authors.initials: JC
authors.lastname: Huang
authors.affiliation: Key Laboratory of Meat Processing and Quality Control, Ministry of Education China, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: J
authors.initials: J
authors.lastname: Yang
authors.affiliation: Institute of Agro-Products Processing Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-Products Processing, Ministry of Agriculture, Beijing 100193, China.
authors.forename: F
authors.initials: F
authors.lastname: Huang
authors.affiliation: Key Laboratory of Meat Processing and Quality Control, Ministry of Education China, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: M
authors.initials: M
authors.lastname: Huang
authors.affiliation: Department of Engineering, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: K J
authors.initials: KJ
authors.lastname: Chen
authors.affiliation: Key Laboratory of Meat Processing and Quality Control, Ministry of Education China, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, 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 China, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: G H
authors.initials: GH
authors.lastname: Zhou
mesh_terms: D000818:Animals; D030161:Avian Proteins / Q000737:chemistry*; D002154:Calpain / Q000737:chemistry*; D002645:Chickens; D003599:Cytoskeleton / Q000737:chemistry; D005260:Female; D006863:Hydrogen-Ion Concentration; D008297:Male; D008460:Meat / Q000032:analysis*; D010369:Pectoralis Muscles / Q000737:chemistry* / Q000378:metabolism; D059748:Proteolysis
chemical_list: D030161:Avian Proteins; D002154:Calpain; C449002:mu-calpain
keywords: autolysis; broiler; calpain; casein zymography; tenderness