Varian cary 50 uv vis spectrophotometer

Five grams of destoned olives were homogenized, added with 10 mL of methanol and vigorously stirred for 20 minutes, then centrifuged at 4000 rpm for 25 min. DPPH-free radical scavenging capacity of phenolic extracts was evaluated according to the following protocol: 200 μL of the extracts or standard (Trolox) was added to 3 mL methanol solution of DPPH radical. After 1 min of vigorous shaking by vortex, the reaction mixture was left to stand at room temperature, in the dark, for 60 min. After that, the absorbance for the sample was read using a Varian Cary 50 UV–vis spectrophotometer (Varian Inc., Middelburg, The Netherlands), at λ = 517 nm, optical path 10 mm. A negative control was taken after adding the DPPH solution to the respective extraction solvent. The free radical scavenging capacity was expressed in Trolox equivalents (TE), e.g., mmol TE/kg, and quantified against a calibration curve of Trolox (r = 0.99).

Chlorophyll and carotenoid concentrations were determined using a Varian Cary 50 UV/Vis spectrophotometer (Varian Inc., Harbour City, CA, USA) following the procedure of Mínguez-Mosquera et al. [37 (link)] and expressed as pheophytin a and lutein content (mg/kg), respectively. Briefly, a sample of oil (7.5 g) was weighed and dissolved in cyclohexane in a 25 mL flask. Chlorophyll and carotenoid concentrations were calculated from the oil absorption spectrum. Absorption at 670 nm is associated with the chlorophyll fraction, whose main component is pheophytin a. The pigment that has the highest concentration in the carotenoid fraction is lutein, and its absorption was measured at 470 nm. The values of the specific extinction coefficients used to calculate the pigment concentrations were E0 = 613 for pheophytin and E0 = 2000 for lutein. The following formulas was used to calculate chlorophyll (6) and for carotenoid (7) concentration: $$\mathrm{Chlorophyll}=\frac{{\mathrm{A}}_{670}\times {10}^6}{613\times 100\times \mathrm{d}}$$
where A₆₇₀ is absorbance on 670 nm, d is thickness of spectrophotometric cuvette, 613 is value of coefficient of specific extinction for phephitin a (E₀);
$$\mathrm{Carotenoid}=\frac{{\mathrm{A}}_{470}\times {10}^6}{2000\times 100\times \mathrm{d}}$$
where A₄₇₀ is absorbance on 470 nm, d is thickness spectrophotometric cuvette, 2000 is value of coefficient of specific extinction for lutein (E₀).

Chlorophyll and carotenoid concentrations were determined using a Varian Cary 50 UV/Vis spectrophotometer (Varian Inc., Harbour City, CA, USA) following the procedure of Mínguez-Mosquera et al. [33 (link)] and expressed as pheophytin a and lutein content, respectively.

Specific spectrometric assays (Varian—CARY^® 50 UV–VIS Spectrophotometer, Varian Inc., The Netherlands) were availed for determination of activities of selected enzymes. Exact procedures for the determination of α-amylase, cellulase, lipase, peroxidase, protease, and transglutaminase activities are precisely described by Leitgeb et al. [97 (link)]. Polyphenol oxidase activity was determined using Creative Enzymes^® protocol [99 ], where the concentration of o-benzoquinone formed from L-DOPA by polyphenol oxidase was measured at 265 nm. Superoxide dismutase activity was determined using a reaction of pyrogallol autoxidation at 325 nm, described by the Creative Enzymes^® protocol [100 ]. The results are reported as units (U) per g of extract. All experiments were carried out in triplicates, and results are presented as mean value ± SD.

The enzyme activity of α-amylase [38 (link)], cellulase [39 (link)], glucoamylase [40 ], laccase [41 (link)], lipase [38 (link)], peroxidase [35 (link)], polyphenol oxidase (PPO) [42 (link)], protease [39 (link)], SOD [43 (link)], and transglutaminase (TGM) [44 (link)] were examined with specific spectrophotometric enzymatic assays for each selected enzyme using a UV spectrophotometer (Varian—CARY^® 50 UV–VIS Spectrophotometer, Varian Inc., Middelburg, The Netherlands). Each assay was performed in three replicates. The results are reported as mean values expressed in units (U) per g of protein.

Varian Cary 50 UV–VIS spectrophotometer
(Agilent Technologies, Santa Clara, CA) was applied to record the
spectra (transmittance mode, range: 200–800 nm, data interval:
0.5 nm), FT-IR spectrophotometer Nicolet iS10 (Thermo Scientific,
Waltham, MA), and Nano ZS instrument (Malvern Instrument, Worcestershire,
UK) were used. GPC measurements were performed using a Malvern Panalytical
OMNISEC chromatograph. The PolySep-SEC GFC-P Linear column, LC Column
300 × 7.8 mm (Phenomenex, Torrance, CA) was used. The flow rate,
injection volume, and polymer concentration were 0.8 mL/min, 100 μL,
and 5 mg/mL, respectively, eluent: 0.1 M NaNO₃ 80/20 H₂O/acetonitrile. Irradiation of photoswitchable heparins was
carried out using 340 nm (trans–cis isomerization)
and 530 nm (cis–trans isomerization) LED lamps
(Thorlabs). Maximum irradiance, E_e, of
the lamps was 0.6 and 9.46 μW/mm², respectively,
at a distance of 200 mm, as given by the manufacturer.