title: Comparison between two different methods to obtain the proportions of myoglobin redox forms on fresh meat from reflectance measurements.
abstract: Two procedures based on reflectance (R) measurements to calculate the proportions of deoxymyoglobin (DMb), oxymyoglobin (OMb) and metmyoglobin (MMb) in meat are recommended by the American Meat Science Association (AMSA). One uses the K/S ratios (K and S are the absorption and scattering coefficients) and the other method (Krzywicki 1979) uses the reflex attenuance A = log (1/R). Both methods were compared in: a) synthetic sets of two pigment mixtures and b) 15 samples of beef Longissimus Lumborum measured after 24 h, 4 and 7 days of exposure to air. It was found that K/S and Krzywicki methods gave different values of pigment proportions. However both methods exhibited a high linear correlation (R(2) = 0.8733 in DMb, R(2) = 0.9771 in OMb and R(2) = 0.9390 in MMb, p < 0.0001). This makes them equivalent for statistical analysis based on differences in pigment proportions.
authors.affiliation: Departamento de Física, Edificio Los Acebos, Universidad Pública de Navarra, Campus Arrosadia, 31006 Pamplona, Spain.
authors.forename: B
authors.initials: B
authors.lastname: Hernández
authors.affiliation: Departamento de Física, Edificio Los Acebos, Universidad Pública de Navarra, Campus Arrosadia, 31006 Pamplona, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Sáenz
authors.affiliation: Departamento de Física, Edificio Los Acebos, Universidad Pública de Navarra, Campus Arrosadia, 31006 Pamplona, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Alberdi
authors.affiliation: Departamento de Física, Edificio Los Acebos, Universidad Pública de Navarra, Campus Arrosadia, 31006 Pamplona, Spain.
authors.forename: J M
authors.initials: JM
authors.lastname: Diñeiro
keywords: Beef; Krzywicki method; Kubelka-Munk theory; Myoglobin states; Pigment proportions; Reflectance