Measurement of Some Citrus Species Content From Total Flavonoids and Antioxidant

s: The aim of this study was to measure content of total flavonoids for most types of citrus cultivated in Iraq as well as the antioxidant activity. The antioxidant was highest in orange peels [5129] micromole Fe+2 / gm dry matter. Citrus peels and seeds are a good source of natural antioxidants that can be used both in the medical and commercial fields .


Raw Material
Five types of citrus fruits grown in Iraq and in Salah al-Din, Wasit, Baghdad and Diyala were used (orange, sour lemon, sweet lemon, Citrus aurantium, and mandarin) from the 2019 crop. Samples were kept in polyethylene bags by lyophilization.

Preparing of extracts
The method mentioned in [12] was used to prepare extracts of peels and seeds and their total flavonoids content were to be measured. 3 gm of sample powder was taken and placed in a 150 ml heat-tolerant beaker, 60 ml of 95% ethanol was added to it, and the beaker was placed in a shaking water bath for 90 minutes. Filter the extract with Whitman No.1 filter paper. Reduce the volume of ethanol using a rotary evaporator until there is residue. 5 ml of methanol was added to the sediment and the extract was placed in a marked test tube and kept in the refrigerator at 4 ° C.
3. Measuring of total flavonoids The total flavonoids were measured according to the method mentioned [13]. 0.5 ml of the required sample extract was taken and placed in a test tube. To it, add 2.5 ml of ethanol and mix it well. 3 ml of aluminum chloride at a concentration of .01 mol was added to it. The tube was left for 10 minutes at room temperature. The optical absorption reading was taken by a Spectrophotometer at a wavelength of 400 nm, as well as for the blank tube that contains all the additives except for the sample extract.
4. Standard curve preparation Standard curve was prepared using Rutin-C₂₇H₃₀O₁₆ at concentrations (5-50) mg / L. Its absorbance readings were taken and a straight-line equation was extracted for use in calibrating the readings and the results were attributed to mg / g dry weight. Fig. 2

Measuring of antioxidant activity
Use the FRAP test. (Ferric Reducing Antioxidant Power) mentioned by [14] and [15]. In which the ferric Fe⁺³ ions are reduced to the Fe⁺² ferrous ions in the presence of antioxidants. The absorbance was measured at a wavelength of 590 nm (the effectiveness of antioxidants is expressed as the amount of iron they consume -micro mol Fe⁺² / g dry weight). Figure 3. shows the content of the citrus species in this study (peels and seeds) of total flavonoids. The results showed that the peel content of flavonoids was higher than that of the seeds and for all types of citrus studied, and this is consistent with what was mentioned [7]. The highest value for lemon was (46.32) mg / g of dry matter. While it reached (40.89, 37.56, 28.34, 4.12) mg / gm in the peel and (11.72, 8.5, 12.8, 1.31) mg / gm in orange, sweet lemon, mandarin and aurantium seeds, respectively.  The results show that the types of citrus under study have antioxidant activity. It showed the highest antioxidant activity in orange peels and reached 5129 micro mol Fe⁺² / g of dry matter. As for the seeds, it was highest in lemon seeds, reaching 147 micro mol Fe⁺² / g form 4. It is higher than what he mentioned [16]. . The results of the research concluded that the secondary wastes of citrus species are a good source of naturally extracted antioxidants that can be used in different areas instead of their industrial counterparts.