In this study, the antimicrobial activity of silver nanoparticles (AgNPs L₂₁, AgNPs L₂₂) produced using aqueous extracts of the Laser trilobum harvested in 2021 and 2022 was optimized. The experimental design and optimization of antimicrobial activity were performed using the response surface method (RSM). Using RSM, independent variables, such as silver concentration, extraction time, and synthesis temperature, were optimized as a result of the inhibition zone diameter against Staphylococcus aureus, Escherichia coli, Salmonella Typhimurium, and Listeria monocytogenes. Based on the optimization results, the extraction time, silver concentration, and temperature for AgNP L₂₁ and L₂₂ synthesis were determined to be 60 min, 5 mM, and 25 °C, respectively. When the XRD and TEM results of the nanoparticles synthesized under optimal conditions were evaluated, it was determined that the AgNPs were spherical in shape and had an average size of 30 ± 12 nm. Our study revealed that the year of harvest is unimportant for nanoparticles synthesized from L. trilobum, using a cheap and simple method that does not require toxic substances. Owing to the antimicrobial activity of nanoparticles produced under optimal conditions, it is possible to biocontrol and prevent contamination by these bacteria in food science and industry.

Research background. Ginseng is a medicinal plant that has anti-inflammatory, antidiabetic, anticancer, antiobesity, cardioprotective, antioxidant and antimicrobial properties. However, previous reports lack information on the effects of ginseng extract on the shelf life and quality characteristics of muscle foods. Thus, it is essential to determine the effects of ginseng extract on the meat model system to gain valuable insights to improve the shelf life and quality of muscle foods. Experimental approach. After determining the in vitro antioxidant activity of ginseng extract, the antioxidant effect of ginseng extract on cooked ground beef was investigated. In vitro antioxidant activity was determined using Fe(III) reducing antioxidant power (FRAP), 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging and total phenolic content (TPC) analyses, while lipid oxidation, chemical, microbiological and textural changes were determined during 30 days of storage. Cooking loss, proximate composition and textural features were measured after thermal processing. The pH, CIE colour parameters, thiobarbituric acid reactive substances (TBARS), lipid hydroperoxide (LPO), total aerobic mesophilic bacteria, total coliform bacteria, yeast and mould counts were determined during refrigerated storage. Results and conclusions. The mean values for FRAP expressed as Fe(II) equivalents ((4.7±0.2) mmol/g), DPPH (IC50=(12.11±0.09) mg/mL) and TPC expressed as gallic acid equivalents ((146.0±2.4) mg/g) showed a potential antioxidant capacity of ginseng extract. The addition of ginseng extract increased the cooking loss (p<0.05), but it did not affect the proximate composition of ground beef. It also caused a decrease in pH (p<0.05). Ground beef samples containing 1 % or more ginseng extract had lower TBARS values than control (p<0.05). In addition, LPO values of ground beef with ginseng extract were lower than the control after 30 days of storage (p<0.05). Total aerobic mesophilic bacteria, total coliform bacteria, yeast and mould were not found in any of the groups, except in the control, which had 3.35 log CFU/g total aerobic mesophilic bacteria at the end of storage. Novelty and scientific contribution. The results show that ginseng extract has an important activity in controlling lipid oxidation and can be used in the meat industry to extend shelf life and microbial stability.