Proteolysis, Lipolysis and Sensory Characteristics of a Tunisian Dry Fermented Poultry Meat Sausage with Oregano and Thyme Essential Oils

Abstract The effects of the addition of oregano (0.25% v/v) and thyme (0.25% v/v) essential oils ( EOs ) on the microbiological, biochemical and sensory characteristics of a Tunisian dry fermented poultry meat sausage were investigated. The antimicrobial activity of oregano and thyme EOs improved the hygienic quality of dry fermented sausages by reducing the Enterobacteriaceae counts, total coliform counts and S taphylococcus aureus counts. Proteolysis was not significantly ( P > 0.05) affected by the addition of EOs during ripening of sausages. In fact, the most abundant free amino acids detected in the final product were arginine, glycine, threonine, alanine, tyrosine, aspartic acid, glutamic acid and lysine. Regarding lipolysis and lipid oxidation, it can be deduced that the addition of oregano and thyme EOs decreased significantly the thiobarbituric acid values during the last two weeks of ripening, but lipolysis was not significantly affected. Finally, the addition of EOs did not significantly affect the sensory properties of sausages. Practical Applications Poultry meat products provide a suitable environment for proliferation of meat spoilage microorganisms. The increase in resistance of food spoilage microorganisms to current preservatives, the consumer's demand for safe and minimally processed foods, and the hazards associated with the use of high doses of chemical preservatives have led to the need for finding safer alternatives in food preservation. Consumers have also become more critical about the use of synthetic additives to preserve food or enhance characteristics such as color and flavor. Hence, there is a growing trend toward minimally processed foods. As a consequence, antibacterial and antioxidant activities of essential oils have received considerable attention in food preservation. Nowadays, the need for safe products with standard and desirable technological properties has resulted in the use of essential oils for the production of the dry fermented sausages to inhibit the growth of undesirable microorganisms and extend the shelf life of the product.