Investigation of antimicrobial and antioxidant effects of extracts obtained from sea lettuce (Ulva lactuca Linnaeus, 1753)

Synthetic antioxidants and antibacterial food additives are indispensable for delivering the product to the consumer safely and in the best quality due to the development of the industry and the growing population. Because of the use of these synthetic additives in processed meats such as salami, the World Health Organization (WHO) and many researchers have reported that consumption of processed meat products causes cancer. In this study, different extracts were produced from a green macroalgae species Ulva lactuca, using acetone, diethyl ether, ethanol, ethyl acetate and petroleum ether and their antibacterial and antioxidant properties were determined by microbiological and chemical analyzes. The extract type which gave optimum results was selected and the possibility of using this extract instead of nitrite and sodium benzoate, which are used as synthetic additives in salami and anchovy paste from processed meat products, was investigated. The products were produced in two separate groups, including synthetic additive and U. lactuca extract and taken into the analysis process. Both product groups were stored at 4 ±1ºC for the duration of the analysis. As a result of the antimicrobial susceptibility tests and chemical analyzes performed, the highest phenolic content and antibacterial activity was detected in the U. lactuca acetone extract. The highest antioxidant activity was detected in U. lactuca petroleum ether extract. U. lactuca acetone extract, in which the most effective antibacterial activity was determined, was preferred in the product studies. In the studies conducted on the product, U. lactuca extracts showed no antimicrobial effect against total psychrophilic aerobic bacteria and yeast-molds counts in anchovy paste and salami but, microbiologically detected under in vitro conditions antibacterial effect of U. lactuca extract against S. aureus was found to be also observed in anchovy paste and salami as product. Considering the effective performance of Ulva lactuca extract by reducing TBA value in salami and anchovy paste and suppressing the increase in TVB-N value, it has been found that it can be advantageous to include U. lactuca extract in the product composition in products where these criteria are used as a quality parameter and with its antimicrobial effect. In addition, it has the potential to be used especially in ready-to-eat-food industry against Staphylococcal intoxications, which are near the top line among the most common food poisoning cases in the world. When only the effectiveness obtained in vitro conditions evaluated there is also possibility for use against other food pathogens, B. cereus and C. jejuni.