EFFECT OF PROPOLIS EXTRACT ON MICROBIOLOGICAL AND COLOR PROPERTIES OF BEEF BURGER DURING REFRIGERATE STORAGE

The demand for natural compounds with bioactive properties to develop meat products healthier has increased. In this sense, própolis has attracted the interest of the food industry due to its biological properties, such as antimicrobial and antioxidant. The objective of this study was to evaluate the effect of propolis extract on microbial and color parameters on beef burgers during refrigerated storage. The control formulation (F1) of the burger was elaborated with (w/w): 78% of beef meat, 15% of sunflower oil, 5% of water, 1.5% of salt, 0.2% of garlic, 0.1% of white pepper and 0.2% of monosodium glutamate. The alcoholic extract of propolis obtained on local market, was added at concentrations (w/v) of 0.5% (F2), 1.0% (F3) and 2.0% (F4) replacing in equivalent amount the water, the samples were stored at 4 °C and analyzed on days 0, 5 and 10. Microbiological determinations included the counts of mesophilic and psychrophilic bacteria, Enterobacteriaceae and yeast and molds. Moreover, the color parameters (L*, a* and b*) were analyzed. Results indicated that propolis extract addition resulted in significant (P<0.05) inhibition of microbial growth, being this effect more intense in the sample with a higher concentration of extract (F4). After the day 10, the red color (a*) decreased (P<0.05), being the decrease more intense in the control sample (8.27±0.51 F1) than in treated samples (11.46±0.43 F2, 11.61±0.19 F3 and 12.00±0.30 F4), resulting in positive effect on appearance. The b* value was always slightly lower in the control sample (7.70±0.02 F1) than in the treated sample (8.70±0.03 F2, 8.77±0.08 F3 and 10.07±0.03 F4), can be justified by the color of the extract. Therefore, although it is necessary to conduct further studies, the incorporation mainly of 2% of propolis extract was technologically viable, due to the reduction of microbial growth and the enhancement of red color.