C37 | Evaluation of the preservative power of apple pomace extract in beef burgers

G. Muratore¹, P. Di Ciccio¹, P. Morra¹, G. Mannino², C. M. Bertea², R. DeS.³, T. Civera¹. | ¹Dip. di Scienze Veterinarie, Torino; ²Dip. di Scienze della Vita e Biologia dei Sistemi, Torino; ³ Separeco srl, Torino.

Microbial contamination of food by spoilage and pathogenic bacteria is one of the main concerns of the food industry. To address this problem, the scientific community is increasingly turning its attention to bioactive molecules derived from agro-industrial by-products. In recent years, numerous studies have been conducted to identify natural alternatives to the additives used in food processing. This approach to valorising food waste represents an innovative strategy for food preservation and an opportunity to increase shelf life. In this context, the following project aims to evaluate the effect of an extract obtained from apple pomace on the microbial profile of beef burgers, together with the impact on their sensory and technological characteristics. Therefore, 5% potato starch, 0.7% salt and 0.05% ground black pepper were added to two batches of minced meat (1.2 kg). All ingredients were mixed for 5 minutes to obtain a uniform mixture, which was then divided into two 600 g units. To one of these, used as a negative control, 5% water was added, while the other was used for the preparation of the treated burgers. In particular, a concentration of 10% apple extract was added to it. Once prepared, the burgers were packaged and stored under refrigerated conditions (0°C - 2°C). Each sample was then subjected to microbiological analysis, pH measurement, colorimetric analysis and determination of weight loss after cooking at 0, 3 and 6 days of storage. Upon preparation, the control and treated burgers showed similar pH values, ranging from 5.86 to 5.91. After 3 and 6 days of storage, however, the pH of the control samples decreased significantly, reaching values of 5.67 and 5.48, respectively, while the treated burgers showed almost constant pH values (5.90 and 5.93, respectively). Furthermore, neither colour nor weight loss were affected by the addition of apple extract during the entire storage period. Regarding the microbial profile, on day 0, the total bacterial count of the control samples was 5.67 log cfu/g. This value increased during the storage period, reaching counts of 6.69 and 6.95 log cfu/g on days 3 and 6. In contrast, the total bacterial count of the treated burgers remained constant, ranging from 5.48 to 5.58 log cfu/g. Finally, throughout the entire storage period, the amount of Enterobacteriaceae and Pseudomonas spp. detected in the treated samples did not show statistically significant differences compared to the levels found in the control burgers. In conclusion, the effect of apple pomace extract on the microbiological profile results in a significant reduction in the total bacterial load of the meat preparations analysed. However, no effect on Enterobacteriaceae and Pseudomonas spp. was observed. Finally, the addition of apple extract did not alter the sensory and technological characteristics.

This work is part of the NODES project, supported by the MUR with PNRR MUR - M4C2 - Investment 1.5 “Innovation Ecosystems” funds, as part of the PNRR financed by the European Union - NextGenerationEU (Grant agreement Cod. n.ECS00000036).