fast antiradical test for monitoring deep fried oils

Fast Antiradical Test Fast Antiradical Test for Monitoring Deep for Monitoring Deep

Fried OilsFried Oils

Dr. Mohamed Fawzy Ramadan HassanienDr. Mohamed Fawzy Ramadan HassanienAssistant Professor, Agricultural Biochemistry DepartmentAssistant Professor, Agricultural Biochemistry Department,,

Faculty of AgricultureFaculty of Agriculture,,Zagazig UniversityZagazig University

EgyptEgypt

5th Euro Fed Lipid Congress, 16-19 September 2007, Gothenburg, Sweden5th Euro Fed Lipid Congress, 16-19 September 2007, Gothenburg, Sweden

The use of fat or oil for frying still remains one of the most The use of fat or oil for frying still remains one of the most popular methods for the preparation of foods world wide.popular methods for the preparation of foods world wide.

Reduce moisture content

Increase oil content Efficient heat transfer

Impart desirable flavors, texture and color

The purposes of The purposes of fryingfrying

Physical and chemical reactions during deep fryingPhysical and chemical reactions during deep frying

. Frying is the most complex Frying is the most complex of all fats and oils of all fats and oils applications.applications.

. . Complex reactions which Complex reactions which take place during frying take place during frying produce both desirable and produce both desirable and undesirable effects on food undesirable effects on food and oil quality.and oil quality.

. Thus, quantifying the . Thus, quantifying the performance of any oil, both performance of any oil, both chemically and nutritionally chemically and nutritionally is extremely difficult if not is extremely difficult if not impossible. impossible.

Perkins and Erickson (1996) Perkins and Erickson (1996) Deep frying; Chemistry, nutrition and practical applicationsDeep frying; Chemistry, nutrition and practical applications . AOCS press. AOCS press

Analysis of deep fried oilsAnalysis of deep fried oils

Disadvantages of conventional analytical methods:Disadvantages 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 of These disadvantages are the reason to search for a new generation of rapid methods for the analysis of deep-frying oils. rapid methods for the analysis of deep-frying oils. As recommended As recommended the methods for control frying oils should be:the 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.

What happens in the FryerWhat happens in the Fryer? ? As deep frying is carried out at high temperatures As deep frying is carried out at high temperatures

(between 160°C and 180°C) and in the presence of air and (between 160°C and 180°C) and in the presence of air and moisture, the physical and chemical properties of the oil change moisture, the physical and chemical properties of the oil change considerably because of hydrolysis, polymerization and considerably because of hydrolysis, polymerization and oxidation. oxidation.

HydrolysisHydrolysis ))action of wateraction of water((PolymerizationPolymerization

FreeFree radical chain process radical chain process

AntioxidantsAntioxidants

)Free radical scavengers(

Can we use the Can we use the remaining remaining

antioxidants to antioxidants to monitor deep-monitor deep-

fryingfrying??

OxidationOxidation

The maximum The maximum permitted level is permitted level is

limited to 200 ppmlimited to 200 ppm

AimAim

The main goal of the work was to compare and correlate the results of physicochemical

parameters and antiradical performance of vegetable oils during deep frying which will be an initial indicator for applying antiradical test

for monitoring deep-frying oils.

The structure of DPPH• (2,2-diphenyl-1-picrylhydrazyl) and its reduction by an antioxidant

DPPH DPPH+H

. DPPH• is widely used to test the ability of compounds to act as free radical scavengers or hydrogen donors and to evaluate antioxidant activity of foods.

. The odd electron in the DPPH free radical gives a strong absorption maximum at 515-517 nm and is purple in color. The color turns from purple to yellow as the molar absorptivity of the DPPH radical reduces from 9660 to 1640 when the odd electron of DPPH radical becomes paired with hydrogen from a free radical scavenging antioxidant to form the reduced DPPH-H.

Principles of Principles of radical scavengingradical scavenging test test

Frying protocol and oil samplingFrying protocol and oil sampling

1- Sunflower oil , cottonseed oil and palm olein1- Sunflower oil , cottonseed oil and palm olein

2- Oil blends (CO2- Oil blends (CO//PO and SOPO and SO//POPO ))

Frying of French fries Frying of French fries

at 180 at 180 °°C for 16 hC for 16 h(replenishment after 8 h)(replenishment after 8 h)

° Sampling after 8 and 16 h Sampling after 8 and 16 h

° °

Analysis of Analysis of physicochemical physicochemical parameters: PV, FFA, TPL, parameters: PV, FFA, TPL, colour, viscosity, colour, viscosity, absorptivity at 232 and absorptivity at 232 and 270 nm270 nm

Ramadan et al. (2006) Ramadan et al. (2006) Eur. J. Lipid Sci. TechnolEur. J. Lipid Sci. Technol. 108: 670-678. 108: 670-678

Radical scavenging Radical scavenging activity (RSA) of oils activity (RSA) of oils toward DPPH radicaltoward DPPH radical

Antiradical testAntiradical test

10 mg of oil + 390 µL toluenic 10 mg of oil + 390 µL toluenic solution (10solution (10-4-4 M M ) of DPPH of DPPH

radicals radicals and the mixture was vortexed and the mixture was vortexed for 20 s at room temperature.for 20 s at room temperature.

Against a blank of pure toluene, Against a blank of pure toluene, the decrease in absorption at the decrease in absorption at 515 nm was measured after 60 515 nm was measured after 60

min of incubation.min of incubation.

° % inhibition% inhibition = [(absorbance of control – = [(absorbance of control – absorbance of test sample)/ absorbance of absorbance of test sample)/ absorbance of

control] x 100.control] x 100.Ramadan et al. (2003) Ramadan et al. (2003) J. Agric. Food ChemJ. Agric. Food Chem. 51: 6961-6969. 51: 6961-6969

Correlation between TPL and RSACorrelation between TPL and RSA

0

5

10

15

20

25

30

35

40

45

50

0 8 16Frying period (h) at 180°C

% Re

maini

ng D

PPH

Sunflower oil

Cottonseed oil

Palm olein

0

1

2

3

4

5

6

7

8

9

10

11

12

0 8 16

Frying period (h) at 180°C

g/100

g oil

Sunflower oil

Cottonseed oil

Palm olein

Levels of total polar compounds (g/100g Levels of total polar compounds (g/100g oil) in different oils during frying of French oil) in different oils during frying of French

friesfries..

Scavenging effect after 60 min incubation Scavenging effect after 60 min incubation of different fried oils on DPPH radical as of different fried oils on DPPH radical as

measured by changes in absorbance measured by changes in absorbance

values at 515 nmvalues at 515 nm.. CC = 0.98CC = 0.98

SuliemanSulieman AM, El-Makhzangy A, Ramadan MF (2006) AM, El-Makhzangy A, Ramadan MF (2006) J. Food LipidsJ. Food Lipids 13: 259-276 13: 259-276

Correlation between absorptivity at 232 nm and RSACorrelation between absorptivity at 232 nm and RSA

0

5

10

15

20

25

30

35

40

45

50

0 8 16Frying period (h) at 180°C

% Re

maini

ng DP

PH

Sunflower oil

Cottonseed oil

Palm olein

Absorptivity at 232 nm of different oils Absorptivity at 232 nm of different oils

during fryingduring frying.. Scavenging effect after 60 min incubation Scavenging effect after 60 min incubation of different fried oils on DPPH radical as of different fried oils on DPPH radical as




0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

0 8 16

Frying period (h) at 180 °C

Abso

rptiv

ity at

232 n

m

Sunflower oil

Cottonseed oil

Palm olein

Correlation between absorptivity at 270 nm and RSACorrelation between absorptivity at 270 nm and RSA

0

5

10

15

20

25

30

35

40

45

50

0 8 16

Frying period (h) at 180°C

% Re

maini

ng DP

PH

Sunflower oil

Cottonseed oil

Palm olein

Absorptivity at 270 nm of different oils Absorptivity at 270 nm of different oils

during fryingduring frying.. Scavenging effect after 60 min incubation Scavenging effect after 60 min incubation of different fried oils on DPPH radical as of different fried oils on DPPH radical as




0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

0 8 16Frying period (h) at 180 °C

Abso

rptiv

ity at

270 n

m

Sunflower oil

Cottonseed oil

Palm olein

Correlation between TPL and RSA of oil blendsCorrelation between TPL and RSA of oil blends

Levels of total polar compounds (g/100g Levels of total polar compounds (g/100g oil) in oils during frying of French friesoil) in oils during frying of French fries..

Scavenging effect after 60 min incubation Scavenging effect after 60 min incubation of fried oil blends on DPPH radical as of fried oil blends on DPPH radical as measured by changes in absorbance measured by changes in absorbance


0

5

10

15

20

25

30

35

40

45

50


% R

emain

ing

DPPH

SO/PO

CO/PO

0123456789

101112

0 8 16

Frying period (h) at 180 °C

g/100

g oil

SO/PO

CO/PO


Correlation between absorptivity at 232 nm and RSA Correlation between absorptivity at 232 nm and RSA of oil blendsof oil blends

Absorptivity at 232 nm of oil blends during Absorptivity at 232 nm of oil blends during

fryingfrying.. Scavenging effect after 60 min incubation Scavenging effect after 60 min incubation

of fried oil blendss on DPPH radical as of fried oil blendss on DPPH radical as measured by changes in absorbance measured by changes in absorbance


0

5

10

15

20

25

30

35

40

45

50


% R

emain

ing

DPPH

SO/PO

CO/PO

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5


Abso

rptiv

ity at

232 n

m

SO/PO

CO/PO


Correlation between absorptivity at 270 nm and RSA Correlation between absorptivity at 270 nm and RSA of oil blendsof oil blends

Absorptivity at 270 nm of oil blends during Absorptivity at 270 nm of oil blends during

fryingfrying.. Scavenging effect after 60 min incubation Scavenging effect after 60 min incubation

of fried oil blends on DPPH radical as of fried oil blends on DPPH radical as measured by changes in absorbance measured by changes in absorbance


0

5

10

15

20

25

30

35

40

45

50


% R

emain

ing

DPPH

SO/PO

CO/PO

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2


Abso

rptiv

ity at

270 n

m

SO/PO

CS/PO


Coincidently, at the same time that our research papers were published, Coincidently, at the same time that our research papers were published, similar research on frying of soybean oil was carried out at Wageningen similar research on frying of soybean oil was carried out at Wageningen University (The Netherlands) wherein similar findings were published by the University (The Netherlands) wherein similar findings were published by the research group of Professor research group of Professor Alphons G. J. VoragenAlphons G. J. Voragen ((J. Sci. Food Agric. J. Sci. Food Agric. 8686:1446–1451, 2006):1446–1451, 2006). In this contribution, antiradical power gives insight into . In this contribution, antiradical power gives insight into early lipid oxidation events during frying of soybean oil rather than early lipid oxidation events during frying of soybean oil rather than hydroperoxides and secondary oxidation products.hydroperoxides and secondary oxidation products.

. The importance of establishing fast and simple methods for quality evaluation of deep frying oils cannot be overemphasized.

. The results allow us to suggest that the rapid antiradical measurement could be used to monitor deep fried oils.

. The results will be also of importance to develop a fast method for monitoring oxidative stability of vegetable oils during storage.

. Antiradical test is highly accurate, non-destructive, easy to use, not expensive, and essentially independent of oil type. However, a more accurate picture of the conclusions need the extension of this investigation to a wider number of samples.

ConclusionConclusion

1- Ramadan MF and Moersel JT (2006) Screening of the Antiradical Action of Vegetable Oils. Journal of Food Composition and Analysis 19: 838-842.

2- Sulieman AM, El-Makhzangy A and Ramadan MF (2006) Antiradical Performance and Physicochemical Characteristics of Vegetable Oils upon Frying of French Fries: A Preliminary Comparative Study. Journal of Food Lipids 13: 259-276.

3- Ramadan MF, Amer MMA and Sulieman AM (2006) Correlation between Physicochemical Analysis and Radical Scavenging Activity of Vegetable Oil Blends 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.

InformationInformation

. . One of the oldest cities One of the oldest cities in Egypt (about 4000 in Egypt (about 4000 years old).years old).. Population: 1 Million.. Population: 1 Million.

Zagazig: City and UniversityZagazig: City and University

. 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

fast antiradical test for monitoring deep fried oils

Health & Medicine

oil sampling1 sunflower

control frying oils

dpph radical absorptivity

c frying period h

dpph free radical

deep frying chemistry

foodand oil quality

nm of different oils