The addition of 100 SO2 mg/kg delayed colour deterioration and myoglobin oxidation in the raw beef patties packaged in air and stored up to 9 days under retail display conditions.
SO2 reduces the myoglobin haem group, which favours the formation of oxymyoglobin and deoxymyoglobin and reduces metmyoglobin, providing a fresh appearance to red meat
The addition of low SO2-extracts, especially ascorbate, delayed even further metmyoglobin formation and contributed to redness stabilization.
According to An et al. (2004), raw beef patties stored in aerobic packaging show a rapid colour deterioration that cannot be stabilized by the sole addition of ascorbate, GTE or GSE.
However, these three extracts combined with 100 mg SO2/kg stabilized redness in raw beef patties to a similar extent as 300 mg SO2/kg.
Other authors found different results.
A high dose (1000 mg GTE/kg) of green tea ethanolic extract can delay the loss of redness in raw pork patties throughout storage.
200–500 mg ascorbate/kg may have a certain effect on redness in beef and buffalo patties or not.