Camellia sinensis EXTRACT ADDED IN BEEF BURGER: EFFECTS ON BACTERIAL QUALITY DURING REFRIGERATED STORAGE

Hamburger is a meat product that due to high amount of nutrients and water is susceptible to bacterial spoilage. The objective of this work was to incorporate a natural extract to hamburger formulation and evaluate its effect on microbiological and physical-chemical characteristics of final product. An extract of green tea (Camellia sinensis) was prepared using 1 g of leaf to 10 mL of cereal alcohol (75%) and was evaluated for total of phenolic compounds by Folin-Ciocalteau method. Three hamburger formulations were elaborated: T1 - control, T2 - 2,5% extract and T3 - 5,0% extract. Microbiological parameters (Enterobacteriacea and Gram-positive coccus), pH and shear force (SF) were evaluated during 0, 3, 7 and 10 days of storage (4 ° C). The extract showed a concentration of total phenolics of 8.02 ± 0.03 mg/g. pH values increased from 5.60; 5.60 and 5.50 on day 0 to 6.17; 5.84 and 6.03 on day 10, for treatments T1, T2 and T3 respectively. Regarding SF, means of treatments with extract addition were lower than control group without tea (0.81 kg / cm² - T2; 0.82 kg / cm² - T3 and 0.94 kg / cm² - T1). For Enterobacteriaceae analysis values ranged from 5.49 log CFU g-1; 4.69 log CFU g-1 and 4.87 logCFU g-1 (T1, T2 and T3 respectively) on day 0 to 6.20 log CFU g-1; 3.94 log CFU g-1 and 3.54 log CFU g-1 on day 10 (T1, T2 and T3). For Gram-positive cocci counting values on day 10 were 4.43 log CFU g-1 for T1; 5.27 log CFU g-1 for T2 and 4.93 log CFU g-1 for T3. Values indicate that tea extract did not inhibit growth of Gram-positive coccus, but showed effect on Enterobacteriaceae group. Thus, C. sinensis extract has potential to be used as a natural preservative in meat.