Genesis 10s uv vis spectrophotometer

An XPert MPD diffractometer was used to record the X-ray diffraction (XRD) patterns of all synthesized materials. The diffractometer was set up with CuK (λ = 1.5406 Å) radiation, a voltage of 40 kV, and a current of 30 mA. At a wavenumber of 400–4000 cm⁻¹, FT-IR spectra were obtained using an 8400S Shimadzu infrared spectrophotometer. SEM pictures of samples were taken using EDAX advanced microanalysis solutions. FESEM studied surface morphology (FE-SEM, JEOL JIB-4610F). N₂ adsorption–desorption was studied using Quantachrome NovaWin Gas Sorption Analyzer. A PerkinElmer Pyris 1 analyzer conducted thermogravimetric analysis (TGA) on a 10 mg sample. Thermograms were taken at 10 °C min⁻¹ air temperatures between 30 and 900 °C. Ultraviolet-visible (UV-vis) spectra recorded on a Thermo Scientific GENESIS 10S UV-vis Spectrophotometer for concentration of dyes after each adsorption.

Baseline diffusion measurements were carried out to ensure porosity of the synthetic membranes prior to AFM measurements. Calibration stock solutions of 5 mg/mL for each FITC-Dextran MW standard (4 kDa or Stokes’ radii of 1.4 nm) dissolved in 0.9% (w/v) NaCl were prepared. In dilute solutions, there is a linear relationship between absorbance and the concentration of the marker under observation, thus diffusion measurements were carried out at this nominal concentration. Dialysis tubing of various MW cutoffs were filled with 2 mL of MW marker solutions and subsequently incubated and stirred at 120 rpm in a 10 mL beaker filled with 0.9% (w/v) NaCl. The supernatant absorbance was measured prior to (A₀) and post-mixing at 350 nm using a Genesis 10 S UV-Vis spectrophotometer (Thermo Fisher Scientific, Waltham, MA, USA). The absorbance value at 8 h (A) was taken to be the equilibrium value.
The molecular weight cutoff (MWCO) of the membrane expressed in terms of Stokes’ radius ( $$r_p$$ ) was given by Equation (1) [45 ]. This equation assumes that the solute of molecular weight (MW) is a sphere with a density (ρ = 1 g·cm⁻³) equal to that of the solute in solid phase.
$$r_p = {\left(\frac{3M_w}{4\rho \pi N_A}\right)}^{1/3}$$

A Genesis 10S UV-Vis Spectrophotometer (Thermo Fischer Scientific, Waltham, MA, USA) was utilized for PA quantification, and polymeric pigment analysis. An Agilent 1260 Infinity HPLC (Agilent Technologies, Santa Clara, CA, USA) equipped with a diode array detector and a 6430 triple quadrupole system was used to analyze phloroglucinolysis reaction products and analyze anthocyanin samples. An Agilent Poroshell 120 SB-C18 HPLC column (4.6 × 150 mm, 2.7 µm) was equipped for the phloroglucinolysis method. An Agilent Poroshell-120 C18 column (2.1 × 50 mm, 2.7 μm) was used for quantitation of anthocyanin samples. The same model Agilent HPLC equipped with only a diode array detector was utilized for gel permeation chromatography (GPC) analysis. An Agilent OligioPore^® column (7.5 × 300 mm, 6 µm) and an Agilent MesoPore^® column (7.5 × 300 mm, 3 µm) were connected in series for the GPC method. Instrument control of the HPLC was performed using MassHunter^® software. Phloroglucinolysis and anthocyanin analysis were performed using Agilent CDS ChemStation^®, and WinGPC^® software (Polymer Standards Service, Philadelphia, PA, USA) was utilized for the GPC analysis.

Tannin levels in seeds were measured using a methyl cellulose-precipitable tannin assay [74 (link)]. Seeds from five berries representative of low- and high-SB groups that exhibited maximum differences in seed weight-to-berry weight ratio were selected for the assay. Seeds from each biological replicate were homogenized in liquid nitrogen and approximately 100 mg of fresh tissue were extracted for 1–2 h with 1 mL of 50% ethanol. Two technical replicates for each extracted sample were used. The appropriate volume of the extract to use in 1 mL reaction was determined through a series of dilutions. The reaction contained the seed extract, 0.04% methyl cellulose solution, and a saturated solution of ammonium sulfate, while parallel blank reactions contained no methyl cellulose polymer. Tannins were precipitated by centrifugation at 14,000 rpm for 10 min and the absorbances of the supernatant for blank and methyl cellulose-containing reactions were measured at 280 nm in glass cuvettes using a Genesis 10S UV–vis spectrophotometer (Thermo Scientific, USA). Epicatechin (Sigma-Aldrich, St. Louis, USA) solutions at different concentrations were used to establish a calibration curve for reporting tannin concentrations as Epicatechin equivalents.

The cheeses were determined for the content of soluble nitrogen (SN), trichloroacetic acid-soluble nitrogen (TCA-SN) and 5% phosphotungstic acid-soluble nitrogen (PTA-SN) using the Kjeldahl method [20 ] and expressed as a percentage of TN. All determinations were made after one, three, and five weeks of ripening.
Cheese proteolysis was determined using the method with o-phthaldialdehyde (OPA), which is based on the reaction of α-amine groups with ortho-phthaldialdehyde (Sigma-Aldrich, Poznań, Poland) and β-mercaptoethanol (Sigma-Aldrich, Poland) at pH 9.0 in the presence of sodium dodecyl sulfate (SDS) (Sigma-Aldrich) after one day, and two, three and five weeks of ripening [21 (link)] The proteolytic activity of all cheese models was determined using 150 μL of the TCA filtrate with 3 mL of o phthaldialdehyde reagent (OPA) according to the method of Church et al. [21 (link)]. Absorbance was measured after mixing (2 min incubation, room temperature, 340 nm) using Genesis 10S UV-VIS Spectrophotometer (Thermo Fisher Scientific, Warsaw, Poland).

The phenylalanine ammonia-lyase (PAL) activity was measured according to Van de Velde et al. (14 (link)) with some modifications. Five grams (5 g) of strawberry by-product with 10 mL of extractant solution (phosphate buffer 100 mmol L^–1 pH 8, EDTA 2 mmol L^–1, PVPP 30 g L^–1, DTT 7 mmol L^–1, Triton X-100 0.1% v/v) were homogenized for 30 s and stirred for 45 min at 4°C. The mixture was centrifuged at 12,000 × g for 20 min at 4°C, and the supernatant was used to assess PAL activity. The reaction mixture was 1060 μL of Tris–HCl 100 mmol L^–1 pH = 8.8, 530 μL phenylalanine 50 mmol L^–1, and 150 μL of enzymatic extract. The reaction mixture was incubated at 37°C for 1 h, the reaction was stopped with 260 μL of TCA 10 g L^–1, and centrifuged at 12,000×g for 10 min. Cinnamic acid production was measured by the absorbance change at 290 nm (Genesis 10S UV–Vis spectrophotometer, Thermo Scientific, Germany). The results were expressed as the change of absorbance by an hour and milligram of protein (ΔA mg protein^–1h^–1).

Soluble protein content was determined with slight modification to the method described by Zhu et al. [110 ] using Coomassie brilliant blue. First, 0.5 g of the leaves of N. tangutorum were ground to a homogenate with 2 mL of phosphate buffer. The supernatant was centrifuged at 12,000 r/min for 20 min at 4 °C. Then, 1 mL of the supernatant, 1 mL of water, and 5 mL of Coomassie Bright blue g-250 were added, followed by centrifugation and subsequent sample oscillation. The light absorbance value was measured at 595 nm using a Genesis 10S UV/Vis spectrophotometer (Thermo Fisher Scientific, Waltham, MA, USA). The same procedure was used to prepare a control using 5 mL of Cowmas bright blue g-250 solution and distilled water. The absorbance was then determined by spectral measurements to determine the protein content using a standard curve.