title: Small heat shock proteins and toughness in intermediate pHu beef.
abstract: Bull M. longissimus dorsi (n=94) categorised into high (n=28), intermediate (n=14) and low (n=52) ultimate pH (pHu) were aged at -1.5°C for 28days. Shear force was higher and more variable (p<0.05) in intermediate pHu samples during ageing. Titin, filamin and desmin degradation was also less extensive in intermediate pHu samples compared to the other two pH categories. The extent of the decline of HSP20, HSP27 and αβ-crystallin concentrations during post mortem ageing was pHu related such that high pHu meat maintained the highest concentration of small heat shock proteins followed by intermediate and low pHu meat. μ-Calpain autolysis was slowest in intermediate pHu and cathepsin B activities remained consistently low during ageing in this group (p<0.05). Meat toughness in the intermediate pHu group may be attributed to the combination of a larger pool of sHSP with a sub-optimal cathepsin B activity and intermediary μ-calpain activities.
authors.affiliation: Food Assurance and Meat Quality, AgResearch Limited, Ruakura Research Centre, Private Bag 3123, Hamilton, New Zealand.
authors.forename: D
authors.initials: D
authors.lastname: Lomiwes
authors.forename: M M
authors.initials: MM
authors.lastname: Farouk
authors.forename: D A
authors.initials: DA
authors.lastname: Frost
authors.forename: P M
authors.initials: PM
authors.lastname: Dobbie
authors.forename: O A
authors.initials: OA
authors.lastname: Young
mesh_terms: D000818:Animals; D001329:Autolysis; D002154:Calpain / Q000378:metabolism; D002401:Cathepsin B / Q000378:metabolism; D002417:Cattle; D064211:Connectin / Q000378:metabolism; D003459:Crystallins / Q000378:metabolism; D003893:Desmin / Q000378:metabolism; D004032:Diet; D064448:Filamins / Q000378:metabolism; D063427:Food Quality; D050886:HSP20 Heat-Shock Proteins / Q000378:metabolism*; D055551:HSP27 Heat-Shock Proteins / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008460:Meat / Q000032:analysis*; D009124:Muscle Proteins / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism*; D011180:Postmortem Changes; D013314:Stress, Mechanical
chemical_list: D064211:Connectin; D003459:Crystallins; D003893:Desmin; D064448:Filamins; D050886:HSP20 Heat-Shock Proteins; D055551:HSP27 Heat-Shock Proteins; D009124:Muscle Proteins; D002154:Calpain; C449002:mu-calpain; D002401:Cathepsin B
keywords: Beef tenderness; HSP20; HSP27; Intermediate pH; Small heat shock proteins; αβ-Crystallin