Quality Maintenance of Beef Burger Patties by Direct Addiction or Encapsulation of a Prickly Pear Fruit Extract

Beef burger patties are a very perishable food product with a maximum shelf life of 3 days at 4°C, due to a fast decrease of quality parameters and microbial growth. Although some additives listed in the Regulation EU 601 (2014) are allowed in fresh minced beef and meat preparations with antioxidant functionality, no additive with antimicrobial activity is permitted. In this study, a prickly pear extract (PPE) was added to beef burger patty formulations both by direct application and encapsulation in alginate beads. Beef burger patties were evaluated during refrigerated storage (up to 8 days at 4°C) in terms of microbial quality, pH, texture, and color variation. At the end of storage, burger samples incorporating PPE and encapsulated PPE showed significantly (p < 0.05) lower values of mesophilic bacteria, Enterobacteriaceae, and Pseudomonas spp. when compared to control samples added with sterile distilled water (SDW) or encapsulated SDW. Samples added with encapsulated PPE showed the smallest variations of color a* values (red) during the considered storage period, followed by samples added with PPE, suggesting a protective effect of the extract toward the myoglobin oxidation process. In addition, textural parameters (hardness, cohesiveness, and springiness) reached the highest levels, after 8 days of storage, in burger samples added both with PPE and encapsulated PPE, supporting the potentiality of PPE, encapsulated or not into alginate beads, to be used as a natural preservative of beef burger patty formulations for maintaining quality parameters.