Five grams of each of the fresh and dried samples was weighed, and approximately 1.5 g of celite was added together with 10 ml of cold acetone. The mixture was ground in a mortar and pestle and transferred into 50‐ml volumetric flask using a glass funnel plugged with cotton wool. The residual was filtered and washed with cold acetone until devoid of color. Fifteen milliliters of petroleum spirit was dispensed into a separating funnel and the acetone extract slowly added followed by distilled water to eliminate residual acetone. The two phases were allowed to separate, and the lower aqueous layer was carefully removed and discarded. The petroleum spirit fraction containing carotenoids was collected into a conical flask through a funnel having anhydrous sodium sulfate (Na2SO4) to dry the layer and topped up to 50 ml with petroleum spirit. Beta‐carotene was determined at 440 nm using UV–vis spectrophotometer (UV mini 1240 model; Shimadzu Corp., Kyoto, Japan). The absorbance of standard solutions was used to generate the standard curves (Rodriguez‐Amaya & Kimura, 2004 ).
Uv mini 1240 model
Manufactured by Shimadzu
Sourced in Japan
The UV mini 1240 is a compact and versatile UV-vis spectrophotometer designed for routine laboratory applications. It features a wavelength range of 190 to 1100 nm and can perform absorbance measurements. The instrument is easy to use and provides reliable performance.
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9 protocols using uv mini 1240 model
1
Quantification of Beta-Carotene in Fresh and Dried Samples
2
Tannin Content Determination in Bean Flours
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Tannin content was determined using the vanillin-HCL method of Price et al. (1978) . About 0.2 g of bean flours was weighed into centrifuge tubes. About 10 ml of 4% methanolic HCL was then added into each of the tubes and then shaken for 20 min on a shaker. The sample mixtures were then centrifuged at 2500 rotations per minute (rpm) for 10 min in a centrifuge (Hettich, D-78532 Tuttlingen, Germany).
The supernatants were transferred into 25-ml volumetric flasks. About 5 ml of 1% methanolic HCL was then added to the precipitate in the centrifuge tubes and centrifuged as described above. The supernatants were then transferred into the 25-ml volumetric flasks above and topped up to the mark using 1% methanolic HCL. About 1 ml of the supernatants was then transferred into two test tubes each. To one test tube, 5 ml of freshly prepared mixed reagent (8% methanolic HCL + 4% vanillin in methanol) was added. To the other test tube, 5 ml of 4% methanolic HCL was added. A series of catechin standards were prepared and 1 ml of each of the standard concentrations transferred into a test tube and 5 ml of the mixed reagent added. The sample extracts and standards were allowed to sit for 20 min for color development. The absorbance of the sample extracts and standard solutions were read at 500 nm using a UV-vis photospectrophotometer (UV mini 1240 model, Shimadzu, Japan).
The supernatants were transferred into 25-ml volumetric flasks. About 5 ml of 1% methanolic HCL was then added to the precipitate in the centrifuge tubes and centrifuged as described above. The supernatants were then transferred into the 25-ml volumetric flasks above and topped up to the mark using 1% methanolic HCL. About 1 ml of the supernatants was then transferred into two test tubes each. To one test tube, 5 ml of freshly prepared mixed reagent (8% methanolic HCL + 4% vanillin in methanol) was added. To the other test tube, 5 ml of 4% methanolic HCL was added. A series of catechin standards were prepared and 1 ml of each of the standard concentrations transferred into a test tube and 5 ml of the mixed reagent added. The sample extracts and standards were allowed to sit for 20 min for color development. The absorbance of the sample extracts and standard solutions were read at 500 nm using a UV-vis photospectrophotometer (UV mini 1240 model, Shimadzu, Japan).
3
Chlorophyll and Carotenoid Quantification
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Frozen samples were processed in a mill and approximately 0.4 g of the obtained powder were added to 2.5 mL of acetone/ water (80/20) and homogenized. The homogenate was vortexed for 1 min and centrifuged at 5500Â g for 5 min. The supernatant was collected and the extraction procedure was repeated with the addition of 2.5 mL of acetone/water (80/20). Chlorophylls and total carotenoids content were determined with spectrophotometer (UV-Mini 1240 model, Shimadzu Corp., Japan) according to Lichtenthaler (1987) and expressed as mg kg À1 of chlorophyll in a fresh weight basis. All measurements were repeated twice.
4
Quantification of Leaf Flavonoids
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Aluminum chloride colorimetric method was used to determine the concentrations of total flavonoids in the leafy vegetables as described by Ebrahimzadeh et al. (2008) (link). 1 mL of the methanolic leaf extract and 4 mL of distilled water were mixed in a 10 mL volumetric flask. 0.3 mL of 5 % sodium nitrite solution was added to the mixture after 3 minutes followed by 0.3 mL of 10 % aluminum chloride after another 3 minutes. 2 mL of 1 M sodium hydroxide was added and the volume was made up to 10 mL with distilled water after 5 minutes.
Absorbances were read at 415 nm using UV-Vis spectrophotometer (Shimadzu, UV mini 1240 model, Tokyo, Japan). Total flavonoids concentrations were calculated from the standard curve prepared using quercetin. The results were expressed as quercetin equivalents (QE) per 100 g of dry sample (g QE/100g DW).
Absorbances were read at 415 nm using UV-Vis spectrophotometer (Shimadzu, UV mini 1240 model, Tokyo, Japan). Total flavonoids concentrations were calculated from the standard curve prepared using quercetin. The results were expressed as quercetin equivalents (QE) per 100 g of dry sample (g QE/100g DW).
5
Measuring O2- Content in Longkong Fruit Pericarp
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To measure the O2− content [33 ] in longkong fruit pericarp, a 4 g pericarp sample was homogenized under cold conditions (4–8 °C) in 12 mL of 50 mmol/L potassium phosphate buffer (pH 7.8) with 1% polyvinylpyrrolidone. The homogenate was then centrifuged at 5000× g for 15 min at 4 °C. Subsequently, 1 mL of the resulting supernatant was combined with 0.9 mL of the same potassium phosphate buffer and 0.1 mL of 10 mmol/L hydroxylamine hydrochloride and this mixture was thoroughly mixed and incubated at 25 °C for 30 min. Following this, 1 mL of the incubated mixture was added to 1 mL of 17 mmol/L metanilic acid and 1 mL of 7 mmol/L 1-naphthylamine. After thorough mixing, this final mixture was incubated again at 25 °C for 30 min. The absorbance of the mixture was then measured at 530 nm using a UV-Vis spectrophotometer (model Mini UV 1240, Shimadzu, Kyoto, Japan). The results were then expressed as nmol g−1 FW.
6
Analytical Methods for Fruit Soluble Solids
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The soluble solids were measured using a refractometer (ABBE AR 1000 S, Megabrix, São Paulo, Brazil). The pH analyses were performed using a pH meter Tecnal, São Paulo, Brazil) . The total titratable acidity was expressed as citric acid (g/100mL) (Latimer, 2019) . The β-carotene and lycopene were extracted and quantified according to the method proposed by Rodriguez-Amaya (2001) with some modifications (Zielinski et al., 2014b) . The samples were analysed in a spectrophotometer (Model Mini UV 1240, Shimadzu) at wavelengths of 450 and 470 nm for β-carotene and lycopene, respectively. The total phenols (TPC) were determined in quadruplicate by colorimetric analysis using Folin-Cicalteu reagent, as described by Singleton and Rossi (1965) , and simultaneous quantification of ascorbic acid (AA), as suggested by Isabelle et al. (2010) . This method is a simple modification of Folin-Ciocalteu assay and it allows to obtain the correct value of total phenols by subtracting the interference of the ascorbic acid.
7
Nitrite and Pigment Analysis of Cooked Chicken
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Representative fresh ground chicken samples from each replication and cooked products were analyzed for residual nitrite contents using the method of AOAC (2007) . Nitrosyl hemochrome and total pigments were measured for cooked chicken samples after extraction with 80% acetone and acidified acetone (Hornsey, 1956 (link)). For nitrosyl hemochrome determination, 10 g of cooked chicken product were blended with 40 mL acetone and 3 mL of distilled, deionized water using a homogenizer (Polytron Model PT10-35, Kinematica AG, Switzerland). The homogenized samples were kept in the dark for 15 min before absorbance measurement. The homogenate was filtered through a Whatman No. 1 filter paper and then the absorbance of the filtrate was measured at wavelength of 540 nm (A540) using a spectrophotometer (Model UV mini 1240, Shimadzu Corporation, Japan). Nitrosyl hemochrome concentration (ppm) = A540 × 290. For total pigment measurement, 10 g of cooked samples were blended with 40 mL acetone, 1 mL HCl, and 2 mL distilled, deionized water and kept in the dark at cold temperature (2-3°C) for 1 h, and then filtered through a Whatman No. 1 filter paper. Absorbance value of the filtrate was measured at wavelength of 640 nm (A640). Total pigment (ppm) = A640 × 680.
8
Analyzing Nitrite and Pigments in Cooked Turkey
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Representative fresh ground turkey samples from each replication and cooked products from each NaCl treatment with the different endpoint cooking temperatures were analyzed for residual nitrite by the method described by AOAC (2007) . Nitrosyl hemochrome and total pigments were measured on cooked turkey samples after extraction in 80% acetone and acidified acetone (Hornsey, 1956 ). For nitrosyl hemochrome determination, 10 g of cooked turkey product was blended with 40 mL acetone and 3 mL distilled, deionized water using a homogenizer (Polytron PT10-35, Kinematica AG, Switzerland). The homogenized samples were kept in the dark for 15 min before absorbance measurement. The homogenate was filtered through a Whatman No. 1 filter paper, and absorbance of the filtrate at 540 nm (A540) was determined using a spectrophotometer (Model UV mini 1240, Shimadzu Corporation, Japan). Nitrosyl hemochrome concentration (ppm) was calculated as: A540×290. For total pigment measurement, 10 g of the cooked samples was blended with 40 mL acetone, 1 mL HCl, and 2 mL distilled, deionized water, kept in the dark at cold temperatures (2–3°C) for 1 h, and then filtered through a Whatman No. 1 filter paper. Absorbance was measured at 640 nm (A640). The total pigment concentration (ppm) was calculated as: A640×680.
9
Carbohydrate Quantification via Anthrone
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Total carbohydrates were quantifiedby an anthrone method according to Morris (1948) .
Absorbance was read at 620nm using UV-Visible Spectrophotometer, Model UVmini-1240 (Shimadzu Corporation, Japan).
Absorbance was read at 620nm using UV-Visible Spectrophotometer, Model UVmini-1240 (Shimadzu Corporation, Japan).
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