title: Effect of calcium chloride, zinc chloride, and water infusion on metmyoglobin reducing activity and fresh lamb color.
abstract: Calcium chloride (CaCl2), zinc chloride (ZnCl2), or water infusions were used to investigate the biochemical factors that affect fresh lamb color, and to examine the role of metmyoglobin-reducing activity in regulating this important quality attribute. Immediately after exsanguination, lamb carcasses (n = 6 per treatment) were infused (10% of BW) with 0.3 M CaCl2, 0.05 M ZnCl2, or water via a catheter inserted into the left carotid artery. The right LM was excised at 24-h postmortem and divided into two halves. The caudal portion was cut into 2.5-cm-thick chops and displayed for 6 d under 1,076 lx of white fluorescent lighting at 2 degrees C, whereas the cranial half was vacuum-packaged and stored at 2 degrees C for 3 wk before retail display. Objective color measurements and samples for biochemical analysis were taken at 0, 1, 3, and 6 d of display. In infused carcasses, pH decline was more rapid (P < 0.05) than in untreated controls, and it was greatest for CaCl2-infused carcasses. Calcium chloride-infused carcasses had lower (P < 0.01) NAD and higher (P < 0.001) NADPH concentrations than water- and ZnCl2-infused or untreated control carcasses. The negative effects of calcium infusion on fresh lamb color, higher (P < 0.01) metmyoglobin accumulation rate, and lower (P < 0.01) L*, a*, and b* color measurements could be explained by the lower amounts of unbound water (P < 0.01), shorter sarcomere length (P < 0.01), lower NAD concentrations (P < 0.01), and higher lipid peroxidation (P < 0.01). Zinc and water-infusions produced less (P < 0.01) lipid oxidation and improved the color and color stability of fresh lamb (P < 0.001). Rate of lipid oxidation in LM chops was greater (P < 0.01) after 3 wk of vacuum-packaged storage than 24-h postmortem. Metmyoglobin-reducing activities (sarcoplasmic and myofibrillar) were decreased in response to infusion treatments (P < 0.001), and ZnCl2 infusion resulted in the lowest metmyoglobin-reducing activities (P < 0.001). A significant association between the myofibrillar metmyoglobin-reducing activity and lipid peroxidation was observed, but metmyoglobin-reducing activities were not associated with any improvement in lamb color. Strategies to increase the antioxidant levels in lamb are very important to improve lamb quality, especially during vacuum-packaging storage.
authors.affiliation: Molecular Biotechnology Group, Agriculture and Life Sciences Division, Lincoln University, Canterbury, New Zealand. bekhita2@lincoln.ac.nz
authors.forename: A E D
authors.initials: AE
authors.lastname: Bekhit
authors.forename: M A
authors.initials: MA
authors.lastname: Ilian
authors.forename: J D
authors.initials: JD
authors.lastname: Morton
authors.forename: L
authors.initials: L
authors.lastname: Vanhanan
authors.forename: J R
authors.initials: JR
authors.lastname: Sedcole
authors.forename: R
authors.initials: R
authors.lastname: Bickerstaffe
mesh_terms: D000818:Animals; D002122:Calcium Chloride / Q000494:pharmacology*; D002712:Chlorides / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D007501:Iron / Q000032:analysis; D015227:Lipid Peroxidation / Q000187:drug effects; D008460:Meat / Q000592:standards*; D008786:Metmyoglobin / Q000032:analysis / Q000187:drug effects*; D018482:Muscle, Skeletal / Q000187:drug effects; D009243:NAD / Q000032:analysis; D009249:NADP / Q000032:analysis; D010084:Oxidation-Reduction / Q000187:drug effects; D010858:Pigmentation / Q000187:drug effects; D011897:Random Allocation; D012518:Sarcomeres / Q000187:drug effects; D012756:Sheep; D013997:Time Factors; D014867:Water / Q000494:pharmacology*; D017967:Zinc Compounds / Q000494:pharmacology*
chemical_list: D002712:Chlorides; D017967:Zinc Compounds; D014867:Water; D009243:NAD; D008786:Metmyoglobin; D009249:NADP; C016837:zinc chloride; D007501:Iron; D002122:Calcium Chloride