Genesys 20 uv vis

LDH activity has been determined according to the procedure of enzyme-based BioMaxima-LDH assay (BioMaxima, PL). Biomaxima-LDH reagent was prepared by mixing R1 and R2 reagents in a 3:1 volume ratio prior to use and then poured into the standard disposable spectrophotometric cuvettes, 1.0 mL per cuvette. 20 μL of culture medium samples filtered through syringe filters (ϕ = 0.2 μm) were added and mixed. Absorbance measurement was performed at 340 nm in 1-min intervals (from 0 to 3 min) using a GENESYS 20 UV−VIS spectrophotometer (Thermo Fisher Scientific, US). The values of LDH activity were calculated based on the following formula: $\mathbf{\text{LDH\hspace{0.17em}activity}}=\mathbf{267.2}\times ∆\mathit{A},\left[\mathbf{\mu }\mathbf{\text{kat}}/{\text{dm}}^{\mathbf{3}}\right]$ where: ΔA–the absorbance change per minute.
Results from three trials were averaged. The value of the standard deviation was calculated.

To evaluate the emulsion stability, the extent of emulsion separation by gravity was assessed by ESI. For this test, 1.0 mL of the freshly prepared, diluted emulsion was transferred to a 20.0 mL test tube and capped to prevent evaporation; tubes were stored at room temperature for 480 min. The absorbance of the diluted emulsions was measured with a UV-Visible spectrophotometer (GENESYS 20 UV-VIS, Thermo Fisher Scientific, USA) at 500 nm in 1 cm path length cuvettes. The percentage of ESI can be identified as the following equation [18 ]: $\begin{array}{c}\%\hspace{0.17em}\hspace{0.17em}\mathrm{E}\mathrm{S}\mathrm{I}=\left(\frac{\mathrm{2.303}A\mathrm{\Delta }t}{\mathrm{\Delta }T}\right),\end{array}$ where T is turbidity at 0 min, A is absorbance at 500 nm, ΔT is change in turbidity over a 480 min period, and Δt is time interval (480 min).