Preservation of fresh ground beef patties using plant extracts combined with a modified atmosphere packaging

High oxygen modified atmosphere packaging of raw ground beef patties favors bright red oxymyoglobin color but also lipid oxidation. Therefore, the effect of the addition of phenolic-rich plant extracts selected for their in vitro antioxidant and antimicrobial activities on microbiological (total viable count, psychrotrophic aerobic bacteria, and coliforms), physico-chemical [pH, exudate mass, thiobarbituric acid-reactive substances (TBARS)], and organoleptic (instrumental color and sensory analysis of cooked patties) quality attributes of beef patties was monitored for 12 days at 4 °C in a high oxygen atmosphere. Prune flesh, pomegranate peel, green tea leaves, grape seed extracts, and Gaillac red wine powder were added at 10 g kg−1 in beef patties. All extracts except prune flesh extract, which had the lowest total phenolic content (3.4 mg gallic acid equivalent (GAE) g−1 against from 81.2 to 570.0 mg GAE g−1 in other extracts), reduced the increase in TBARS in beef patties over 12 days by more than 93% (P < 0.05). While all plant extracts significantly inhibited the in vitro growth of at least 1 from the 6 unwanted bacterial strains which were tested, their effect on total viable and psychrotrophic bacterial counts in beef patties was not significant (P > 0.05). In vitro and in situ antioxidant activities of plant extracts were correlated with their total phenolic content (R2 = 0.99) unlike in vitro (R2 = 0.18) and in situ (R2 = 0.17) antibacterial activities. Interestingly, pomegranate peel extract and Gaillac red wine powder retarded lipid oxidation and color variation, and maintained the redness index of meat.