Dataset in the characterization of black spot Ehrenberg snapper and its proteins' denaturation inhibition by natural antioxidants

The data represented in this paper describe techniques, methodologies and data obtained during the biochemical composition characterization of Blackspot Snapper (Ehrenberg's Snapper). Data analysis of protein, lipids, moisture, ash contents of Ehrenberg's snapper, total polyphenols, total flavonoids contents and the DPPH scavenging activities of Cinnamon (Cinnamomum verum J. Presl) bark (50 mg/50 g), cumin (Cuminum cyminum L.) (50 mg/50 g), turmeric (Turmerica longa L.) (50 mg/50 g), garlic (Allium sativum L.) (50 mg/50 g), ginger (Zingiber officinale Roscoe) (50 mg/50 g) and Vitamin C (25 mg/50 g) are represented. Data obtained from the Infrared spectroscopy (FTIR) analysis of the six spices and vitamin C treated and stored fillets at −25 °C, namely three vibrations, Amide A, NH stretching at 3300 cm−1; Amide I, C=O stretching 1600−1690 cm−1 and Amide II, CN stretching and NH bending at 1480−1575 cm−1. Differential scanning calorimetry (DSC) analysis data of three main denaturations; myosin, actin and sarcoplasmic proteins are presented.


Data
Here we report experimental data on proteins' denaturation of Ehrenbergs' Snapper (Lutjanus ehrenbergii) locally known as (Naiser) which fall within the green category according to the consumer guide produced by Emirates Wildlife Society, in association with the World Wide Fund for Nature (EWS-WWF) [2]. This guide helped in the identification of more sustainable species. Calibration curves for assays for polyphenols, flavonoids contents and DPPH scavenging activity of garlic, ginger, cumin, turmeric and cinnamon are presented in (Figure S1, S2 and S3 respectively, included in Supplementary documents). While data, of total phenolic contents presented in mg (gallic acid)/100 g (dry weight of biomass), flavonoids presented as ppm of rutin and DPPH scavenging activity given in inhibition (%), are given in Table 1. Fish samples were prepared using protocol shown in Fig. 1. The biochemical characterization of Ehrenberg snapper includes; lipids content, peroxide value, moisture content, ash analysis, proteins content are presented in Fig. 2. The metal content of ash are represented in Table 2. The effect of 50.0 mg biomass/50 g mince  [1].

Value of the Data
The research represents a very useful data for proteins' denaturation inhibition by using natural antioxidants. These data are relevant to food conservation, especially sustainable fish species and provide more understanding of factors affecting proteins' denaturation. These data gave a detailed and complete set of experiments that could be used in the characterization of various fish species and provide an insight on how gels, pastes and surimi could be prepared from seafood. The data reveal new ways in which widely used natural antioxidants presumably used to inhibit protein denaturation and develop more sustainable and innovative products from widely available stocks of fish and save overfished categories.
fillets treated with cinnamon, cumin, turmeric, garlic, ginger and 25.0 mg of vitamin C was studied to assess protein denaturation during a period of 4 weeks storage time at À25.0 C. FT-IR stretching vibration of Amide-A (n NH ) at 3300 cm À1 ; Amide-I stretching (n C ¼ O ) between 1600 and 1690 cm À1 and Amide-II stretching (n CN ) and bending (d NH ) between 1480 and 1575 cm À1 were used as marker peaks, these are presented from Fig. 3. Averages of transmittances of the marker peaks run in triplicate for different antioxidant treated and non-treated samples frozen at À25 C for 1 week, 2 weeks, 3 weeks and 4-weeks storage time were summarized in Table 3. Descriptive analysis one-way ANOVA and pair-wise comparison of mean values of different variables obtained from Table 3 and summarized in Table S1 (in Supplementary material) were performed using SPSS 15.0 version, the t-test were used with a significant level of p < 0.05. The data are presented from Table S2 to  V13A3, V13A4, V13A5, V13A6, V13A7, respectively, where 13 denotes first week and numbers from 1 to 7 denote antioxidants; reference, cinnamon, garlic, ginger, turmeric, cumin and vitamin respectively. Similar coding was used for other weeks. Comparison was made in two different ways; a horizontal comparison to assess the effect of antioxidant, the t-test in this case was performed with a reference variable V13A1 and all other variables V13A2 V13A3 V13A4 V13A5 V13A6 V13A7, the code used in SPSS to calculate p values in this case is given as Code 1. While the vertical comparison was made to assess the effect of time, in this case comparison was made through the same categories; amide A (week-1) with amide A (week-2). The code used in this case is presented as Code 2. We finally analyzed the effect of 50.0 mg biomass/50 g mince fillets treated with cinnamon, cumin, turmeric, garlic, ginger and 25.0 mg of vitamin C on protein denaturation during a period of 4 weeks and storage time of À25.0 C using DSC, three marker peaks were followed, myosin, sarcoplasmic proteins and actin. Thermograms are represented in Fig. 4, peaks ( C) and enthalpies (J/g) obtained for different antioxidants treated mince fillets from DSC are summarized in Table 4. 2. Experimental design, materials, and methods

Natural antioxidant extraction
Natural antioxidants, cinnamon sticks, cumin seeds, ginger powder, turmeric powder and fresh garlic paste were purchased from the local market of Aljubail, Sharjah, the United Arab Emirates. Cinnamon sticks, cumin seeds were grided while fresh garlic was crushed in a mortar to get a past. 5.0 g of each spice were extracted with 100 mL of water or methanol in 250 mL conical flasks which were left   4000  3500  3000  2500  2000  1500  1000  500  4000  3500  3000  2500  2000  1500  1000  500   4000  3500  3000  2500  2000  1500  1000  500  4000  3500  3000  2500  2000  1500  1000    in horizontal mechanical shaker for a period of 2 hours at 80 C. The spice extract were filtered on an 11.0 mm pore size Whatman filter, the filtrates were dried on a rotary evaporator and 150 mg obtained powders were dissolved in 100 mL of water or methanol and transferred to amber bottles and stored in the fridge for further analysis. 50 mg of vitamin C however were dissolved in water or methanol were used as synthetic antioxidant reference. Methanol extracts were used for tests of total polyphenols analysis, total flavonoids analysis and DPPH scavenging activity, while water extracts were used for the marinating of the fish sample to study the effect of antioxidant on the protein denaturation inhibition in Ehrenberg's snapper.

Total phenolic contents
Total phenolic contents in garlic, ginger, cumin, turmeric and cinnamon were determined by using the protocol described in Ref. [3]. 1.00 mL of natural antioxidant (spice) containing 1.00 mg/mL of dray mass of spice were mixed with 1.0 mL of Folin-Ciocalteu's phenol. The solution was incubated for 5 min at 23.0 C, then 10.0 mL of a 7.00 (m/V)% sodium carbonates (Na 2 CO 3 ) solution were added to the mixture. 13.0 mL of deionised water was added to the mixture to diluted it and was shacked with the rotamixer for a period of 1.0 min. The reaction mixture was kept in the dark at a temperature of 23.0 C for 90 minutes then absorbances were measured at 750 nm using a spectrophotometer (UV-2510TSeLabomed). The same procedure was followed for the standard of pure gallic acid with concentration ranging from 25.0 to 400 mg/L. Results were expressed in mg of gallic acid equivalent per 100 g of sample dry mass (mg (GAE)/100 g DW).

Total flavonoids content
Rutin was used to construct the calibration curve to measure the contents of spices in flavonoids, a standard curve of rutin in the range of 10.0e80.0 ppm was prepared from 400 ppm stock solution. Flavonoids were measured according to the method described by Ref. [4]. 0.300 mL of each methanolic extract (stock solution, 150.0 mg/100 mL) of natural antioxidant (spice) were introduced into In 10.0 mL test tubes and were mixed separately with 3.40 mL of 30.0 (v/v)% methanol, 0.15 mL of 0.50 M sodium nitrate (NaNO 2 ) and 0.15 mL of 0.30 M aluminium chloride hexahydrate (AlCl 3 .6H 2 O), the mixture was incubated at 23.0 C for a period of 5 min. 1.00 mL of 1.0 M sodium hydroxide (NaOH) was added to the mixture. A blank was prepared by mixing the same reagents without any antioxidant extracts. Sample solutions and standards were homogenized, then absorbances were measured at 356 nm using a UV-VIS Spectrophotometer (UV-2510TSeLabomed).

DPPH scavenging activity
DPPH radical was used to assess the scavenging activity of total polyphenols present in natural antioxidants as well as vitamin C. The test performed using the protocol described in Ref. [5].
In summary, in 5 test tubes containing 2.50 mL of mathanolic extract of natural antioxidant (stock solution 150 mg/100 mL), 2.00 mL of 0.50 mM of 2,2-diphenyl-1-picrylhydrazyl (DPPH) freshly prepared in methanol were added. The mixtures were incubated at 23.0 C for a period of 30 minutes to allow reactions to take place. The UVeVis absorbances were measured at a wavenumber of 517 nm using a UV-VIS Spectrophotometer (UV-2510TSeLabomed). Methanol was used as a blank. Absorbances of stock solutions represent the control absorbance (A before ) of the test and A after is the test's absorbance.

Lipid extraction
In the thimble of soxhlet apparatus mounted on a around bottle flask containing 90.0 mL of petroleum ether on the top of a heating mantle, 10.0 g of Ehrenberg's snapper's freshly prepared mince fillets. The mince fillets were extracted in the apparatus for a period of 3 hours, then, the extraction solvent was evaporated in the rotary evaporator. The mass of oil obtained was measured on analytical balance.

Peroxide value (PV)
Primary oxidation of Ehrenberg snapper's oil and the measurement of hydroperoxides were determined by peroxide value analysis, that consist of measuring the amount of iodine formed by the reaction of peroxides formed in fat or oil with iodide ion. The test was performed using protocol described by Ref. [6]. In 250 mL conical flask containing 10.0 mL of chloroform (CHCl 3 ), 15.0 mL of glacial acetic acid (CH 3 COOH) and 1.00 mL of freshly prepared potassium iodide (KI), 0.18 g of fish oil extracted by soxhlet apparatus. The conical flask was tightly closed and gently swirled to allow its contents to mix for 1 min and kept for another 1 min in the dark. 1.00 mL of starch solution (2.00% m/v) and 75.0 mL distilled water were added to the mixture. The solution was titrated with 0.01 M sodium thiosulfate (Na 2 S 2 O 3 ). The indicator was added towards the end of the titration while the pale straw colour is still present. The solution was shaken during titration until the blue colour disappeared. A blank titration was carried out under the same conditions on a mixture containing all reagents used in the test except the oil. No more than 0.50 mL of 0.01 M sodium thiosulfate solution should be consumed for this purpose.

Proteins content
Proteins content measurement was carried based on the concept that the amino acids building blocks of protein when digested will be converted to ammonia. The test was carried out using the Kjeldahl procedure described in Ref. [7]. 1.00 g of the minced fillets was digested in 20 mL of (H 2 SO 4 , 96%) together with two selenium catalyst tablets (5.0 g K 2 SO 4 ; 0.15 g CuSO 4 .5H 2 O; 0.15 g TiO 2 ). The mixture was boiled in a distillation apparatus for 2 hours. The digestion of the minced fillets continued until a clear solution was developed. Then the flask was left to cool down for 15 minutes. This technique is based on the conversion of nitrogen present in proteins to ammonia in the form of ammonium sulphate. 20.0 mL of 0.50 M sodium hydroxide (NaOH) was added to allow the release of ammonia via steam distillation in the distillation apparatus, and the distillate was collected over 25.0 mL of boric acid (4.00% m/v) then titrated against a standard solution of 0.05 M sodium carbonates (Na 2 CO 3 ) using methyl orange as indicator.
2.8. Moisture content 5.00 g of fresh fish tissue were placed in three pre-weight glass watch, then heated in an oven preset in 100 C. The glass watch were kept in the oven for a period of 24 hours, then taken and cooled in a desiccator. The moisture content was determined form the mass difference between empty and desiccator dried glass watch.
2.9. Ash content and X-ray fluorescence (XRF) analysis 6.00 g of fresh fish tissue were placed in three pre-weight silica dishes. The dishes were heated on a hot plate under the fume hood for a period of 10 min until moisture was removed completely, then they were placed in a programmed muffle furnace set at final temperature of 550 C with a speed of 10 C/min, the samples were kept at this final for a period of seven hours. Ash obtained in the silica dishes were taken measured and taken to XRF analysis to determine the fish composition in metals to look for any toxic heavy metals. The XRF machine was (XGT-7200 X-ray Analytical Microscope e Horiba).