Browsing by Subject "Discoloration"

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Influence of different storage atmospheres in packaging on color stability of beef
(2024) Krell, Johannes; Poveda‐Arteaga, Alejandro; Weiss, Jochen; Witte, Franziska; Terjung, Nino; Gibis, Monika
The influence of storage atmosphere on the color development and myoglobin (Mb) redox state of beef was investigated. Beef samples were packaged in 6 different atmospheres including different degrees of vacuum, levels of oxygen, nitrogen, and a mixture with 20% CO2 and stored at 2°C for 14 days. Over this time, color and reflection of the packaged samples were measured. The used method allows quick, easy, and non‐invasive measurement of the packaged samples, without using time consuming chemical assays. The method could be implemented in beef production lines, with potential for automatization. The data was used to illustrate the L*a*b* values for insights regarding qualitative color changes. Quantitative color changes were analyzed by calculation of color difference ΔE2000. Additionally, the relative levels of the deoxymyoglobin (DMb), oxymyoglobin (OMb) and metmyoglobin (MMb) were calculated from reflection spectra. The most important findings are: there is a strong correlation (rsp = 0.80 to 0.99 with one exception at rsp = 0.69 (high vacuum), p ≤ 0.05) between a* values and relative OMb levels. Storage atmospheres containing high oxygen concentrations lead to an attractive meat color, but a decreased overall color and Mb stability (ΔE = 5.02 (synthetic air) and ΔE = 2.23 (high oxygen) after 14 days of storage). Vacuum packaged samples are most stable in regards of color and Mb stability (ΔE = 1.79 (high vacuum) and ΔE = 1.63 (low vacuum) after 14 days of storage), but lack in the vibrant red color desired for sale. The experiments showed that color measurement can be a fast, non‐invasive marker for meat quality.Practical ApplicationIn this research article, six different storage atmospheres are compared regarding their influence on color stability and color quality of beef during storage in packaging. The results suggest which atmospheres to use in various sales‐related scenarios. The method described can easily be applied in the meat industry to quickly monitor changes during storage and wet‐aging without damaging the meat or opening the meat packages.
Influence of low oxygen concentrations on color stability of modified atmosphere packaged beef
(2026) Krell, Johannes; Aeckerle, Luis; Poveda-Arteaga, Alejandro; Weiss, Jochen; Terjung, Nino; Gibis, Monika
The influence of low oxygen concentrations on the development of color and the myoglobin redox states over storage time was analyzed, to determine whether there are conditions that increase discoloration. Beef slices were packaged in atmospheres containing nitrogen gas and 0 %, 0.5 %, 1 %, 1.5 %, 3 %, and 5 % of oxygen. The samples were stored at 2 °C for 14 days. During storage, color, reflectance and oxygen concentration were measured optically through the packaging. The color difference ΔE2000 and the relative oxymyoglobin (OMb), deoxymyoglobin (DMb), and metmyoglobin (MMb) levels were calculated. After 14 days, the oxygen concentrations changed to 0.09 % (0 %), 0.36 % (0.5 %), 0.92 % (1 %), 1.28 % (1.5 %) 2.55 % (3 %), and 4.29 % (5 %). Regarding MMb formation, the 0 % samples (ΔMMb0–14d 11.1 %) were significantly (p < 0.05) more stable compared to the other samples, which showed an increase of MMb formation with rising oxygen concentration after 14 days. The other samples reached a ΔMMb0–14d increase of 21.1 % (0.5 %), 26.7 % (1 %), 30.0 % (1.5 %), 31.1 % (3 %), and 34.4 % (5 %). The color stability showed significantly (p < 0.05) increasing ΔE values of 2.49 (0 %), 3.39 (0.5 %), 4.66 (1 %), 5.14 (1.5 %), 6.03 (3 %), and 7.34 (5 %) with rising oxygen contents. These findings suggest that to ensure the color stability of beef with minimal MMb formation, it is important to completely exclude oxygen from the packages, since the destabilizing effect of oxygen already started at 0.5 %. The non-invasive measurement of the oxygen concentration and the reflectance data over 14 days gave new insights into the discoloration process of beef stored in low-oxygen atmospheres.