title: Mechanism for lactate-color stabilization in injection-enhanced beef.
abstract: In two experiments, the relationship between metmyoglobin (MMb) reduction and lactate to pyruvate conversion with concomitant production of reduced nicotinamide adenine dinucleotide (NADH) via lactic dehydrogenase (LDH) was investigated. In experiment 1, nonenzymatic reduction of horse MMb occurred in a lactate-LDH-NAD system. Exclusion of NAD+, L-lactic acid, or LDH resulted in minimal MMb reduction. Increasing NAD+ and L-lactic acid concentrations increased reduction. In experiment 2, beef strip loins (longissimus lumborum muscle) were injected with combinations of potassium lactate, sodium tripolyphosphate, sodium chloride, and/or sodium acetate. Steaks were packaged in high-oxygen (80% oxygen/20% carbon dioxide) modified-atmosphere packaging and stored for 2-9 days and then placed in a fluorescent-lighted, open-top display case for 5 days at 1 degrees C. Enhancing loins with 2.5% potassium lactate significantly increased LDH activity, NADH concentration, MMb-reducing activity, and subsequent color stability during display. These research results support the hypothesis that enhancing beef with lactate replenishes NADH via increased LDH activity, ultimately resulting in greater meat color stability.
authors.affiliation: Department of Animal Sciences and Industry, Weber Hall, Kansas State University, Manhattan, Kansas 66506, USA.
authors.forename: Yuan H
authors.initials: YH
authors.lastname: Kim
authors.forename: Melvin C
authors.initials: MC
authors.lastname: Hunt
authors.forename: Richard A
authors.initials: RA
authors.lastname: Mancini
authors.forename: Mark
authors.initials: M
authors.lastname: Seyfert
authors.forename: Tom M
authors.initials: TM
authors.lastname: Loughin
authors.forename: Donald H
authors.initials: DH
authors.lastname: Kropf
authors.forename: J Scott
authors.initials: JS
authors.lastname: Smith
mesh_terms: D000818:Animals; D002417:Cattle; D003116:Color; D004355:Drug Stability; D005511:Food Handling / Q000379:methods*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D007773:Lactates / Q000008:administration & dosage* / Q000378:metabolism; D008460:Meat / Q000032:analysis*; D008786:Metmyoglobin / Q000737:chemistry*; D009243:NAD / Q000378:metabolism; D010084:Oxidation-Reduction
chemical_list: D007773:Lactates; D009243:NAD; D008786:Metmyoglobin; D007770:L-Lactate Dehydrogenase