Fast Antiradical Test for Monitoring Deep      Fried Oils Dr. Mohamed Fawzy Ramadan Hassanien ,Assistant Professor, Agricu...
The use of fat or oil for frying still remains one of the mostpopular methods for the preparation of foods world wide.    ...
Physical and chemical reactions during deep frying. Frying is the most complexof    all   fats  and   oilsapplications.. C...
Analysis of deep fried oilsDisadvantages of conventional analytical methods:1- Highly time-consuming and labor-intensive.2...
?What happens in the Fryer         As deep frying is carried out at high temperatures(between 160°C and 180°C) and in the ...
Aim    The main goal of the work was to compare  and correlate the results of physicochemical    parameters and antiradica...
Principles of radical scavenging test. DPPH• is widely used to test the ability of compounds to act as free radicalscaveng...
Frying protocol and oil sampling        1- Sunflower oil , cottonseed oil and palm olein              2- Oil blends (CO/PO...
Antiradical test             10 mg of oil + 390 µL toluenic               solution (10-4 M ) of DPPH                      ...
Correlation between TPL and RSA             12                                                                            ...
Correlation between absorptivity at 232 nm and RSA                           0.5                                          ...
Correlation between absorptivity at 270 nm and RSA                          2                                             ...
Correlation between TPL and RSA of oil blends             12                                                              ...
Correlation between absorptivity at 232 nm and RSA                   of oil blends                          0.5           ...
Correlation between absorptivity at 270 nm and RSA                   of oil blends                          2             ...
Coincidently, at the same time that our research papers were published,similar research on frying of soybean oil was carri...
Conclusion. The importance of establishing fast and simple methodsfor quality evaluation of deep frying oils cannot beover...
Information  1- Ramadan MF and Moersel JT (2006) Screening of the Antiradical Action ofVegetable Oils.Journal of Food Comp...
Zagazig: City and University                   . One of the oldest cities                   in Egypt (about 4000          ...
Fast Antiradical Test for Monitoring Deep Fried Oils
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Fast Antiradical Test for Monitoring Deep Fried Oils

  1. 1. Fast Antiradical Test for Monitoring Deep Fried Oils Dr. Mohamed Fawzy Ramadan Hassanien ,Assistant Professor, Agricultural Biochemistry Department ,Faculty of Agriculture Zagazig University Egypt 5th Euro Fed Lipid Congress, 16-19 September 2007, Gothenburg, Sweden
  2. 2. The use of fat or oil for frying still remains one of the mostpopular methods for the preparation of foods world wide. The purposes of Reduce moisture content fryingIncrease oil content Efficient heat transfer Impart desirable flavors, texture and color
  3. 3. Physical and chemical reactions during deep frying. Frying is the most complexof all fats and oilsapplications.. Complex reactions whichtake place during fryingproduce both desirable andundesirable effects on foodand oil quality.. Thus, quantifying theperformance of any oil, bothchemically and nutritionallyis extremely difficult if notimpossible. Perkins and Erickson (1996) Deep frying; Chemistry, nutrition and practical applications. AOCS press applications.
  4. 4. Analysis of deep fried oilsDisadvantages of conventional analytical methods:1- Highly time-consuming and labor-intensive.2- The possible use of large volume of solvents (potential environmental problem).3- High purchasing cost.4- Necessary calibration with reference substances.These disadvantages are the reason to search for a new generation ofrapid methods for the analysis of deep-frying oils. As recommendedthe methods for control frying oils should be:1- Rapid tests that would correlate with internationally recognized standard methods.2- Show ease in application provide for safe use in food processing.3- Give quantification of oil degradation.4- Independent of type of food and fat.
  5. 5. ?What happens in the Fryer As deep frying is carried out at high temperatures(between 160°C and 180°C) and in the presence of air andmoisture, the physical and chemical properties of the oil changeconsiderably because of hydrolysis, polymerization andoxidation. Hydrolysis Polymerization )action of water( Oxidation Free radical chain process Can we use the remaining antioxidants to The maximum Antioxidants monitor deep- permitted level is limited to 200 ppm )Free radical scavengers( ? frying
  6. 6. Aim The main goal of the work was to compare and correlate the results of physicochemical parameters and antiradical performance ofvegetable oils during deep frying which will bean initial indicator for applying antiradical test for monitoring deep-frying oils.
  7. 7. Principles of radical scavenging test. DPPH• is widely used to test the ability of compounds to act as free radicalscavengers or hydrogen donors and to evaluate antioxidant activity of foods.. The odd electron in the DPPH free radical gives a strong absorptionmaximum at 515-517 nm and is purple in color. The color turns from purple toyellow as the molar absorptivity of the DPPH radical reduces from 9660 to1640 when the odd electron of DPPH radical becomes paired with hydrogenfrom a free radical scavenging antioxidant to form the reduced DPPH-H. DPPH DPPH+H The structure of DPPH• (2,2-diphenyl-1-picrylhydrazyl) and its reduction by an antioxidant
  8. 8. Frying protocol and oil sampling 1- Sunflower oil , cottonseed oil and palm olein 2- Oil blends (CO/PO and SO/PO ) Frying of French fries at 180 °C for 16 h (replenishment after 8 h) ° Sampling after 8 and 16 h Radical scavenging Analysis of physicochemical parameters: PV, FFA, TPL, activity (RSA) of oils ° colour, ° viscosity,toward DPPH radical absorptivity at 232 and 270 nm Ramadan et al. (2006) Eur. J. Lipid Sci. Technol . 108: 670-678
  9. 9. Antiradical test 10 mg of oil + 390 µL toluenic solution (10-4 M ) of DPPH radicals and the mixture was vortexed for 20 s at room temperature. Against a blank of pure toluene, the decrease in absorption at 515 nm was measured after 60 min of incubation.% inhibition = [(absorbance of control – absorbance of ° test sample)/ absorbance of control] x 100. Ramadan et al. (2003) J. Agric. Food Chem . 51: 6961-6969
  10. 10. Correlation between TPL and RSA 12 50 11 Sunflower oil 45 Sunflower oil 10 Cottonseed oil 40 Cottonseed oil 9 8 35 Palm olein Palm olein 7 30 % Remaining DPPHg/100g oil 6 25 5 20 4 15 3 2 10 1 5 0 0 0 8 16 0 8 16 Frying period (h) at 180°C Frying period (h) at 180°C Levels of total polar compounds (g/100g Scavenging effect after 60 min incubation oil) in different oils during frying of French of different fried oils on DPPH radical as .fries measured by changes in absorbance .values at 515 nm CC = 0.98 Sulieman AM, El-Makhzangy A, Ramadan MF (2006) J. Food Lipids 13: 259-276
  11. 11. Correlation between absorptivity at 232 nm and RSA 0.5 50 0.45 45 Sunflower oil 0.4 40 0.35 35 Cottonseed oil 0.3 30 Palm oleinAbsorptivity at 232 nm 25 % Remaining DPPH 0.25 0.2 Sunflower oil 20 0.15 15 Cottonseed oil 0.1 10 0.05 Palm olein 5 0 0 0 8 16 0 8 16 Frying period (h) at 180 °C Frying period (h) at 180°C Absorptivity at 232 nm of different oils Scavenging effect after 60 min incubation of different fried oils on DPPH radical as .during frying measured by changes in absorbance .values at 515 nm CC = 0.99 Sulieman AM, El-Makhzangy A, Ramadan MF (2006) J. Food Lipids 13: 259-276
  12. 12. Correlation between absorptivity at 270 nm and RSA 2 50 1.8 45 Sunflower oil 1.6 40 1.4 35 Cottonseed oil 1.2 30 Palm oleinAbsorptivity at 270 nm 25 % Remaining DPPH 1 0.8 20 Sunflower oil 0.6 15 Cottonseed oil 10 0.4 0.2 Palm olein 5 0 0 0 8 16 0 8 16 Frying period (h) at 180 °C Frying period (h) at 180°C Absorptivity at 270 nm of different oils Scavenging effect after 60 min incubation of different fried oils on DPPH radical as .during frying measured by changes in absorbance .values at 515 nm CC = 0.99 Sulieman AM, El-Makhzangy A, Ramadan MF (2006) J. Food Lipids 13: 259-276
  13. 13. Correlation between TPL and RSA of oil blends 12 50 11 SO/PO 45 SO/PO 10 9 40 8 35 CO/PO 7 CO/PO 30 6g/100g oil % Remaining DPPH 5 25 4 20 3 15 2 10 1 5 0 0 0 8 16 0 8 16 Frying period (h) at 180 °C Frying period (h) at 180 °C Levels of total polar compounds (g/100g Scavenging effect after 60 min incubation .oil) in oils during frying of French fries of fried oil blends on DPPH radical as measured by changes in absorbance .values at 515 nm CC = 0.98 Ramadan et al. (2006) Eur. J. Lipid Sci. Technol . 108: 670-678
  14. 14. Correlation between absorptivity at 232 nm and RSA of oil blends 0.5 50 0.45 45 SO/PO 0.4 40 0.35 35 CO/PO 0.3 30Absorptivity at 232 nm 0.25 % Remaining DPPH 25 0.2 SO/PO 20 0.15 15 0.1 CO/PO 10 0.05 5 0 0 0 8 16 0 8 16 Frying period (h) at 180 °C Frying period (h) at 180 °C Absorptivity at 232 nm of oil blends during Scavenging effect after 60 min incubation of fried oil blendss on DPPH radical as .frying measured by changes in absorbance .values at 515 nm CC = 0.99 Ramadan et al. (2006) Eur. J. Lipid Sci. Technol . 108: 670-678
  15. 15. Correlation between absorptivity at 270 nm and RSA of oil blends 2 50 1.8 45 SO/PO 1.6 40 1.4 35 CO/PO 1.2 30Absorptivity at 270 nm % Remaining DPPH 1 25 0.8 20 SO/PO 0.6 15 0.4 10 CS/PO 0.2 5 0 0 0 8 16 0 8 16 Frying period (h) at 180 °C Frying period (h) at 180 °C Absorptivity at 270 nm of oil blends during Scavenging effect after 60 min incubation of fried oil blends on DPPH radical as .frying measured by changes in absorbance .values at 515 nm CC = 0.99 Ramadan et al. (2006) Eur. J. Lipid Sci. Technol . 108: 670-678
  16. 16. Coincidently, at the same time that our research papers were published,similar research on frying of soybean oil was carried out at WageningenUniversity (The Netherlands) wherein similar findings were published by theresearch group of Professor Alphons G. J. Voragen (J. Sci. Food Agric.86:1446–1451, 2006). In this contribution, antiradical power gives insight intoearly lipid oxidation events during frying of soybean oil rather thanhydroperoxides and secondary oxidation products.
  17. 17. Conclusion. The importance of establishing fast and simple methodsfor quality evaluation of deep frying oils cannot beoveremphasized.. The results allow us to suggest that the rapid antiradicalmeasurement could be used to monitor deep fried oils.. The results will be also of importance to develop a fastmethod for monitoring oxidative stability of vegetable oilsduring storage.. Antiradical test is highly accurate, non-destructive, easyto use, not expensive, and essentially independent of oiltype. However, a more accurate picture of the conclusionsneed the extension of this investigation to a wider numberof samples.
  18. 18. Information 1- Ramadan MF and Moersel JT (2006) Screening of the Antiradical Action ofVegetable Oils.Journal of Food Composition and Analysis 19: 838-842. 2- Sulieman AM, El-Makhzangy A and Ramadan MF (2006) AntiradicalPerformance and Physicochemical Characteristics of Vegetable Oils uponFrying of French Fries: A Preliminary Comparative Study.Journal of Food Lipids 13: 259-276. 3- Ramadan MF, Amer MMA and Sulieman AM (2006) Correlation betweenPhysicochemical Analysis and Radical Scavenging Activity of Vegetable OilBlends as Affected by Frying of French Fries.European Journal of Lipid Science and Technology 108: 670-678. 4- Ramadan MF (2007) Monitoring Deep Frying Oils.Inform 18: 139-141.
  19. 19. Zagazig: City and University . One of the oldest cities in Egypt (about 4000 years old). . Population: 1 Million. . Zagazig University was established 1974 and it include 20 colleges. . Faculty of Agriculture was also established 1974 and it consist of 16 departments. www.zu.edu.eg

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