After 4 days of storage, both indexes registered very high
standard deviations due to the presence of spots of oxidized
myoglobin and spots of deoxygenated myoglobin. The transient
discoloration, as previously observed for myoglobin forms, made
the determination of exact values of the colorimetric indexes
impossible. The results are neither shown nor discussed given that
they are not considered useful in defining the minimum blooming
time for the patties.
After 8 and 10 days of storage in master bags, we observed
(Table 4) an increase in the C* values from 0 to 30 min, then it had
stabilized and until the end of blooming (300 min) values
comparable to those at time 0 were observed. After 8 and 10 days
of storage in master bags, the Hue angle values were quite similar
and approximately 12.6; this value is correlated with the red
portion of the color space, in particular, the dark-red zone. H
increased after only 30 min of blooming and then remained
constant at approximately 18, corresponding to the bright-red
color space, for the entire period monitored (300 min).
These changes reflected the shift in the meat color from a
purple-red hue, typical of a high concentration of DMb, to a brightred
color caused by the oxygenated pigments. As previously
observed in myoglobin evaluation, the blooming phenomenon
occurred faster after longer storage under anaerobic conditions
due to the lower competition for available molecular oxygen
between meat pigments and biological activities. Additionally, no
differences (p < 0.05) between samples wrapped with perforated
(P) and unperforated (UP) films were detected (data not shown).
In view of the above considerations, the blooming time for the
ground meat patties was set at 2 h.