Quail breasts were individually wrapped with food-grade polyvinyl chloride (PVC) film (thickness: 8.5 µm ± 8%; breaking load: >17 N/mm; extension: >135%; temperature range: from −30 °C to +40 °C) to prevent direct air contact and stored in a refrigerator for an eight-day retail display trial. The refrigerator was set at 4 °C ± 1 °C, and continuous cold fluorescent light illumination (L58 W⁄840 LUMILUX Cool White, Osram, Germany) was provided for the whole period to simulate commercial retail conditions. Analyses were performed at days 0 (24 h postmortem) and 8 of refrigerated storage. For storage drip loss calculation, the quail breasts were removed from the refrigerator, unwrapped, and weighed. The pH and L*a*b* color values were measured (in duplicate) on the same breast portions using the same instruments described previously. After physical evaluation, the breasts were ground with a Retsch Grindomix GM 200 (7000 g for 10 s) and were used to determine the extent of muscle lipid oxidation. The latter was evaluated with a spectrophotometer (Hitachi U-2000; Hitachi, Mannheim, Germany) set at 532 nm that measured the absorbance of thiobarbituric acid-reactive substances (TBARs) and a 1,1,3,3-tetraethoxypropane calibration curve [24 (link)]. Oxidation products were quantified as malondialdehyde (MDA) equivalents (mg MDA/kg muscle).
U 2000
Manufactured by Hitachi
Sourced in Japan, United States, United Kingdom
The U-2000 is a UV-Visible spectrophotometer manufactured by Hitachi. It is a compact, single-beam instrument designed for general laboratory applications. The U-2000 is capable of measuring the absorbance or transmittance of samples within a wavelength range of 190 to 1100 nanometers.
Automatically generated - may contain errors
Lab products found in correlation
Whatman, by Cytiva (6 mentions)
Hplc system, by Shimadzu (3 mentions)
Fg2 five gotm, by Mettler Toledo (2 mentions)
Whatman number 2v filter, by Cytiva (2 mentions)
Mathematica, by Wolfram (2 mentions)
1 15p microcentrifuge, by Merck Group (2 mentions)
Sp0810, by Shimadzu (2 mentions)
Biomate 3, by Thermo Fisher Scientific (1 mentions)
Folin ciocalteu reagent, by Merck Group (1 mentions)
Gallic acid, by Merck Group (1 mentions)
Cellulose acetate filters, by Cytiva (1 mentions)
Toc 5000, by Shimadzu (1 mentions)
Elemental combustion system, by Costech (1 mentions)
Spectraa 220, by Agilent Technologies (1 mentions)
Zetapals, by Brookhaven Instruments (1 mentions)
Rpmi 1640 culture medium, by Thermo Fisher Scientific (1 mentions)
Glutathione (gsh), by Merck Group (1 mentions)
Alanine, by Merck Group (1 mentions)
Hemin, by Merck Group (1 mentions)
Cysteine, by Merck Group (1 mentions)
107 protocols using u 2000
1
Quail Breast Shelf-life Evaluation
2
Quantitative Determination of Triterpenes
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The total triterpenoid content of the Water-Vbr and EtOH70%-Vbr extracts was determined using a colorimetric method [58 (link)] with modifications. Briefly, 100 μL of the extract was mixed with vanillin/glacial acetic acid (150 μL, 5% (p/v)) and perchloric acid solution (500 μL). The sample solutions were heated at 60 °C for 45 min and then cooled to room temperature. Subsequently, 2.25 mL of glacial acetic acid was added, and the absorbance was measured at 765 nm using a spectrophotometer Hitachi U-2000 (Tokyo, Japan). Oleanolic acid was used as the standard control. Measurements were obtained in triplicate, and the mean and standard deviation values were adjusted using a straight-line equation (Y = 0.0013x + 0.0858 and R2 = 0.9991). The results are presented as the mean (±SD) of oleanolic equivalents per gram of the extract.
3
Egg Storage Stability Evaluation
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The storage stability trial was carried out on 16 eggs/treatment. At egg collecting date (n = 8 eggs/treatment) and at day 28 of storage (n = 8 eggs/treatment), albumen pH and yolk thiobarbituric acid-reactive substances (TBARs) were measured. The pH was analyzed with a portable pH meter FG2-Five GoTM (Mettler Toledo, Greifensee, Switzerland) which was calibrated at pH 4.0, 7.0, 9.0 and 12. The extent of egg yolk lipid oxidation (TBARs) was evaluated with a spectrophotometer (Hitachi U-2000; Hitachi, Mannheim, Germany) set at 532 nm, that measured the absorbance of TBARs and a 1,1,3,3-tetraethoxypropane calibration curve [29 (link)]. Oxidation products were quantified as malondialdehyde (MDA) equivalents (mg MDA/kg egg yolk).
4
Quantifying Lipid Oxidation in Meat
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The extent of lipid oxidation in meat was determined by measuring the thiobarbituric acid reactive substances (TBARS) after 1 and 7 days of refrigerated storage of meat using the procedure described by Botsoglou et al. [36 (link)]. Five grams of ground meat were homogenized with 10 mL of 5% trichloroacetic acid in an Ultraturrax at 21,280× g for 1 min. Butylated hydroxytoluene was added prior to homogenization at a level of 125 μg/mg of fat. The blended sample was filtered through Whatman number 2V filter (Whatman International Ltd., Maidstone, UK) and 2.5 mL of the filtrate were mixed with 1.5 mL of 0.8% thiobarbituric acid in distilled water in capped test tubes. Tubes were vortexed, incubated at 70 °C for 30 min and absorbance was determined at 532 nm using an ultraviolet-visible spectrophotometer Hitachi U-2000 (Hitachi, Ltd.). Results were expressed as mg of malondialdehyde (MDA) per kilogram of muscle after the preparation of a standard curve of 1,1,3,3-tetraethoxy propane.
5
ABTS Radical Scavenging Activity Assay
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ABTS radical scavenging activity of extracts was determined as previously described [28 (link)]. Initially, ABTS stock solution containing 5 ml of 2.45 mM potassium persulfate was mixed with 5 ml of 7 mM ABTS+ solution to produce ABTS radical cation (ABTS+). Then, the mixture was allowed to stand in the dark at room temperature for 12–16 h prior to use. Methanol was used to dilute the ABTS+ solution to a final concentration that would give an absorbance of 0.70 ± 0.02 at 734 nm. About 100 μl of extracts was added to 900 μl of ABTS solution. This solution was vortexed for 15 s and the absorbance was measured at 734 nm after 6 min using a UV visible spectrophotometer (Hitachi U-2000; Hitachi, Tokyo, Japan). Vitamin C was used as reference standard at final concentrations in range of 0.025 to 1 mg/ ml. The scavenging activity of test sample was calculated and expressed as the IC50 using the following formula:
Where Ac is the absorbance of the control, and As is the absorbance of sample.
Where Ac is the absorbance of the control, and As is the absorbance of sample.
6
Carotenoid and Chlorophyll Extraction
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Carotenoid and chlorophyll of fresh leaves were extracted with 80% (v/v) acetone and then measured with a UV−visible spectrophotometer (Hitachi−U2000, Hitachi, Ltd., Tokyo, Japan) according to the previous method [56 (link)]. UV−Vis spectrophotometer with a mounted 126 integrating sphere (BioMate 3S, Thermo Fisher Scientific Inc., MA, USA) was used to determine leaf absorption as described previously [51 (link)].
7
Meat Lipid Oxidation Quantification
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The meat lipid oxidation was assessed by measuring the thiobarbituric acid reactive substances (TBARS) after 1 and 7 days of refrigerated storage of meat using the procedure described by Botsoglou et al. [27 (link)]. Five grams of ground meat were homogenized with 10 mL of 5% trichloroacetic acid containing 100 μL of 2% butylated hydroxytoluene in an Ultraturrax at 21,280× g for 1 min. The blended sample was centrifuged (3000 rpm for 5 min at 4 °C), filtered through Wathman number 2V filter (Whatman International Ltd., Maidstone, UK) and 2.5 mL of the filtrate were mixed with 1.5 mL of 0.8% thiobarbituric acid in capped test tubes, that were vortexed and incubated at 70 °C for 30 min. Absorbance was determined at 532 nm using an ultraviolet-visible spectrophotometer Hitachi U-2000 (Hitachi, Ltd., Chiyoda-ku, Tokyo). Results were expressed as mg of malondialdehyde (MDA) per kilogram of muscle after the preparation of a standard curve of 1,1,3,3-tetraethoxy propane.
8
Measuring Egg Yolk Lipid Oxidation
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The extent of yolk lipid oxidation was determined by measuring the TBARS in fresh eggs (day 0) and after four months of storage of eggs at room temperature, using the procedure described by Botsoglou et al. [38 (link)] with minor modifications. Two grams of yolk were homogenised with eight millilitres of 5% trichloroacetic acid in an Ultraturrax at 21,280× g for 1 min. Butylated hydroxytoluene was added prior to homogenisation at a level of 125 μg/mg of fat. The blended sample was filtered through Whatman number 2V filter (Whatman International Ltd., Maidstone, UK) and 1.5 mL of the filtrate was mixed with 1 mL of 0.8% thiobarbituric acid in distilled water in capped test tubes. Tubes were vortexed, incubated at 80 °C for 30 min and absorbance was determined at 532 nm using an ultraviolet-visible spectrophotometer Hitachi U-2000 (Hitachi, Ltd., Tokyo, Japan). Results were expressed as mg of malondialdehyde (MDA) per kilogram of yolk after the preparation of a standard curve of 1,1,3,3-tetraethoxy propane.
9
Poultry Meat Quality Analysis
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After physical evaluations, all right breasts were ground with a Retsch Grindomix GM 200 (7000 g for 10 s); an aliquot of about 20 g/breast was dedicated to the thiobarbituric acid-reactive substances (TBARs) analysis, whereas the remaining meat/breast was frozen at −40 °C, freeze-dried and ground again (7000 g for 5 s) to obtain a fine powder which was used to determine: proximate composition, FA profile and cholesterol content. The left legs were thawed for 12 h at 4 °C, deboned and then they were processed following the same procedure described for breast meat samples. The same meat quality evaluations conducted on the right breasts, were performed on the left legs.
The proximate composition of breast and leg meat samples was analyzed in accordance with the AOAC [16 ] methods. The cholesterol content was determined through absolute quantitative analysis using HPLC following the method described by Casiraghi et al. [17 ]. The extent of muscle lipid oxidation was evaluated with a spectrophotometer (Hitachi U-2000; Hitachi, Mannheim, Germany) set at 532 nm, that measured the absorbance of TBARs and a 1,1,3,3-tetraethoxypropane calibration curve [18 (link)]. Oxidation products were quantified as malondialdehyde (MDA) equivalents (mg MDA/kg muscle).
The proximate composition of breast and leg meat samples was analyzed in accordance with the AOAC [16 ] methods. The cholesterol content was determined through absolute quantitative analysis using HPLC following the method described by Casiraghi et al. [17 ]. The extent of muscle lipid oxidation was evaluated with a spectrophotometer (Hitachi U-2000; Hitachi, Mannheim, Germany) set at 532 nm, that measured the absorbance of TBARs and a 1,1,3,3-tetraethoxypropane calibration curve [18 (link)]. Oxidation products were quantified as malondialdehyde (MDA) equivalents (mg MDA/kg muscle).
10
Quantification of Polyphenols in Diverse Samples
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For the extraction of polyphenols in GP, GE, diets and excreta, 0.50 g of sample was placed in a capped centrifuge tube, suspended in 20 mL of acidic methanol/water (50:50 v/v, pH = 2) and thoroughly shaken at room temperature for 1 h. The tube was centrifuged at 3500 rpm for 15 min and the supernatant was separated. Twenty millilitres of acetone/water (70:30 v/v) was added to the residue and shaking and centrifugation were repeated. The methanol and acetone extracts were combined and used for TEP quantification. The TEP content was determined by Folin–Ciocalteu procedure [36 (link)]. Briefly, a mixture of 0.5 mL of extract, 0.5 mL of Folin–Ciocalteu reagent (Sigma-Aldrich, St. Louis, MO, USA) and 10 mL of 1 M Na2CO3 were introduced in a 25 mL volumetric flask. After reacting for 1 h, absorbance was measured at 750 nm using an ultraviolet-visible spectrophotometer (Hitachi U-2000; Hitachi, Ltd., Tokyo, Japan). Absorbance values were compared against a standard curve made with gallic acid (Sigma-Aldrich, St. Louis, MO, USA) ranging from 0.05 to 0.5 mg of gallic acid per mL. Results were expressed as grams of gallic acid equivalents (GAE) per 100 g of DM.
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