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Thermoluminscence of irradiated herbs and spices
Radial.
Phys.
C/tern.
Vol.
Copynght
THERMOLUMINESCENCE OF IRRADIATED AND SPICES A. MAMOON, Department
44, No.
l/2. pp.
203-206,
1994
4~; 1994
Elsevier Science Ltd Printed in Great Britain. All rights reserved 0969-806X194 $6.00 + 0.00
Pergamon
of Nuclear
Engineering,
A. A. ABDUL-FATTAH Faculty Jeddah
HERBS
and W. H. ABULFARAJ
of Engineering, P.O. Box 9027, King Abdulaziz 21413, Saudi Arabia
University.
Abstract-Several types of herbs and spices from the local market were irradiated with different doses of y radiations. Doses varied from a few kilograys to 10 kilograys. Thermoluminescence of the irradiated samples and their controls was investigated. For the same type of herb or spice glow curves of different magnitudes, corresponding somewhat to the doses given, were obtained from the irradiated samples. Most control samples gave little or insignificant glow. Glow curves from different herbs and spices irradiated with the same doses were not similar in the strength of the glow signal given. Samples of the black pepper obtained from different packages sometimes give glow curves of very different intensities. Samples from irradiated black pepper were found to show little fading of their glow curves even at 9 months postirradiation. All irradiations were done under the same experimental conditions and at a dose rate of approximately 1 kGy h-‘. The glow curves were obtained using a heating rate of about 9°C s-’ and a constant nitrogen flow rate.
dose rate which was about 1 kGy h-‘. Control samples were processed the same way except for not being irradiated. The glow curves were obtained for the controls and irradiated samples using a Harshaw system model 2000. A linear heating rate of about 9°C SK’ and a constant nitrogen flow was flushing the measuring cell for all the experiments. Heating ranged from 50 to 300°C and the intensity of the thermoluminescent (TL) emission was measured in units of nano coulombs (nC).
INTRODUCTION
Food preservation by gamma irradiation has been found successful for several food items. Several techniques are currently used for identifying irradiated foodstuffs, among them: electron spin resonance (Wieser and Regulla, 1988) seed germination (Uchiyama et al., 1989) and thermoluminescence (Biigl, 1989, 1990; Delincee et al., 1988; Delincee, 1989; Heide and Biigl, 1988; Sanderson et al., 1989). In view of the widespread irradiation preservation of herbs and spices much interest developed for studying the thermoluminescence of herbs and spices in the local market since most of it is imported. The aim of this study is to establish baseline data on thermoluminescence of control and irradiated herbs and spices locally available such that it becomes possible to set up a program for identification of irradiated herbs and spices.
RESULTS AND DISCUSSION
EXPERIMENTAL
Several types of herbs and spices in different packages were obtained locally and were irradiated with different doses of gamma radiation. A Gammacell 220 (AECL, Canada) irradiator loaded with 6oCo was used. Several samples from each type of herb or spice were used in the experiments and the samples were irradiated with doses varying from few kGy to 10 kGy. Ten mg samples were used for the glow curves. The samples were placed in discs cut from 0.5 mm aluminum sheet such that they fit the heater planchette. The doses were given at almost the same 203
All irradiated herbs and spices gave TL emissions above that for the controls in varying degrees. The intensities of the TL varied for the different herbs and spices for the same doses. For the same herb or spice, the TL signal was usually somewhat proportionate to the doses received. The glow curves peaked at about 150°C for most samples. The TL signals from ginger, cinnamon, thyme, turmeric, paprika, cumin, rosemary and some black pepper samples (Figs 1, 3, 4, 5, 7, 8, 9, 13 and 14) were relatively less intense than those from sweet paprika, chili and some black pepper varieties (Figs 2, 6, 10, 11 and 12). Furthermore some packaged samples of black pepper gave TL signals very different in intensities as shown in Figs 10, 11 and 12, for the same doses. Sanderson et al. (1989) investigated the origins of the TL signals from herbs and spices and has shown that they are due to usually very low levels of inorganic matter. The differences in the intensities of TL signals from different herbs and spices reported in the present work could be due to differences in the nature and amounts of dust or inorganic materials
204
A. MAMOON er al.
1O-l
v
C *
10
Paprika
=
3
0
u C 303
5
2
w .!I +
20-
f4 w
2
.: I-
lo-
2 2
1
6 :: 0 0
3
3; u-l
%
4
Cumin
8-
u C
2 g
,ISweet
40-
*-
;: S “: -I t-
50
Ginger
iq6i 0
0
0
400
200
TEM!?I*C
TEt.lPI°C
Fig. 1.
Fig. 2.
3
4
1
h 0
20
40
TEMP.
I°C
Fig. 3.
15Chili
Turmeric
1 0 0 TEMF!
/ OC
TEMP.1
Fig. 4.
Of
1
0
I
200
200 TEMP.
“C
Fig. 5.
I
4 IO 1°C
Fig. 6.
.I
4(
260
TEMl?I°C
TEMP.
Fig. 7
Fig. 8. Figs l-9
(legend opposile)
Fig. 9.
’ I ‘C
4 IO
Thermoluminescence
of irradiated
20s
herbs and spices
80.
Black
Pepper
260 TEMP.
I OC
IEMP.
: OC
Fig. 1 I.
Fig. 10.
Fig. l-l I. Typical glow curves obtained at different doses for some irradiated rate was 9°C SK’ and they dose rate approximately 1 kGy h-‘. Curve I: control; 3: dose 6 kGy.
adhering to the samples of herbs and spices. This could be due, perhaps, to differences in the nature of the soils supporting these herbs and spices, in addition to variations in implementing hygienic conditions in their collection from the fields. The degree of contamination with dusts and other inorganic material can apparently vary even for samples of the same type of spice but obtained from different packages or containers, as shown for the case of black pepper samples given the same dose (Figs 10 and 11). The fading of the TL signal vs time was tested by irradiating two black pepper samples from the same container with same doses. The TL signal from one sample was obtained shortly after end of irradiation
herbs and spices. Heating curve 2: dose 3 kGy; curve
(Fig. 13) while the other sample was stored at room temperature and a TL signal was obtained from it after about nine months (Fig. 14). It can be seen that there was little fading in the signal with time although there appears to be some broadening of the TL signal. The slow fading of the TL signal, was even more pronounced when the TL signal was obtained from separated inorganic material from irradiated spice, as was reported by (Gbksu-ijgelman and Regulla, 1989). A half life for the TL signal in this latter case was determined to be about 5 years at room temperature.
Black
Pepper
200
0 400 Fig. 12. Typical glow curves obtained at different doses for some irradiated herbs and spices. Heating rate was 9 C SK’ and the y dose rate approximately I kGy h- ‘. Curve : control; curve 2: dose 6 kGy; curve 3: dose IO kGy.
200
400
TEMPIV Fig. 13. Typical glow curves obtained at different doses for some irradiated herbs and spices. Heating rate was 9°C s-’ and the ;’ dose rate approximately 1 kGy h-‘. Curve I: control; curve 2: dose I kGy; curve 3: dose 2 kGy: curve 4: dose 3 kGy; curve 5: dose 4 kGy.
A. MAMOON et al.
206
2.c Black
Pepper
Acknowledgemenrs~The authors wish to thank Zaheer, Mr S. Abu-Abdullah, Mr S. Wajed and Sharif for their help with parts of this work.
Dr A. Mr H.
REFERENCES
” z z In E w I -1 *
1.5
BogI K. W. (1989) Identification of irradiated foods methods, developments and concepts. Inl. J. Appl. Radial. losrop. 40,
l.C
0.5
Fig. 14. Typical glow curves obtained at different doses for some irradiated herbs and spices; similar irradiated sample as that in Fig. 13 but the glow curve was obtained after 9
months post-irradiation. Heating rate was 9°C s-’ and the 7 dose rate approximately 1kGy h- ‘. Curve 1: control; curve 2: dose 1kGy; curve 3: dose 2 kGy; curve 4: dose 3 kGy; curve 5: dose 4 kGy.
BogI K. food. Delincee fying
1203- 1210.
W. (1990) Methods
for identification of irradiated 35, 301-3 IO. H. (1989) Luminescence measurements for identiirradiated spcies and herbs. Int. Work.~hop on Food Irradiafion, Hsinchu, Taiwan, pp. I18 127. Delincee H., Ehlermann D. A. E. and BogI K. W. (1988) The feasibility of an identification of radiation processed food. In Healrh Impact, Idenr(jicarion and Dosimerry o/ Irradiated Foods. Report of a WHO Working Group, Bericht des Instituts fur Strahlenhygiene des BundesgeISH- 125. Neuherberg, pp. 58 127. sundheitsamtes, Germany. Goksu-Cjgelman H. Y. and Regulla D. F. (1989) Detection of irradiated food. Narure 340, 23. Heide L. and BogI K. W. (1988) Thermoluminescence and chemiluminescence measurements as routine methods for the identification of irradiated spices. In Health Impacf. Idenrification, and Dosimetry qf Irrudiured Foods. Report of a WHO Working Group, Bericht des Instituts fur Strahlenhygiene des Bundesgesundheitsamtes ISH- 125. Neuherberg, pp. 2077232. Sanderson D. C. W.. Slater C. and Cairns K. .I. (1989) Thermoluminescence of foods: origins and implications for detecting irradiation. Rudiur. Phys. Chem. 34, Radial.
Php.
Chrm.
915924.
It can be concluded from the experiments carried out that identification of irradiated herbs and spices can be done in most cases. However, since apparently both the dose received and the nature and amount of contaminating inorganic material, affect the intensity of the signal, assessment of the dose received from only the TL signal obtained from the whole spice can be subject to error.
Uchiyama S.. Konno S., Toyooka M., Kawamura Y. and Saito J. (1989) Studies of identification of gammairradiation grapefruit by germination method. J. Food H_vg. SW. Jap. 30, 152~ 159. Wieser A. and Regulla D. F. (1988) Identification of irradiated spices by ESR spectroscopy. In Hrullh Impuct. Idenr#icufion and Dosimefrv of’ Irrudiutcd Foods. Report of a WHO Working Group. Bericht des Instituts fur Strahlenhygiene des Bundesgesundheitsamtes ISH-125. Neuherberg, pp. I5 I I6 I.
Phys.
C/tern.
Vol.
Copynght
THERMOLUMINESCENCE OF IRRADIATED AND SPICES A. MAMOON, Department
44, No.
l/2. pp.
203-206,
1994
4~; 1994
Elsevier Science Ltd Printed in Great Britain. All rights reserved 0969-806X194 $6.00 + 0.00
Pergamon
of Nuclear
Engineering,
A. A. ABDUL-FATTAH Faculty Jeddah
HERBS
and W. H. ABULFARAJ
of Engineering, P.O. Box 9027, King Abdulaziz 21413, Saudi Arabia
University.
Abstract-Several types of herbs and spices from the local market were irradiated with different doses of y radiations. Doses varied from a few kilograys to 10 kilograys. Thermoluminescence of the irradiated samples and their controls was investigated. For the same type of herb or spice glow curves of different magnitudes, corresponding somewhat to the doses given, were obtained from the irradiated samples. Most control samples gave little or insignificant glow. Glow curves from different herbs and spices irradiated with the same doses were not similar in the strength of the glow signal given. Samples of the black pepper obtained from different packages sometimes give glow curves of very different intensities. Samples from irradiated black pepper were found to show little fading of their glow curves even at 9 months postirradiation. All irradiations were done under the same experimental conditions and at a dose rate of approximately 1 kGy h-‘. The glow curves were obtained using a heating rate of about 9°C s-’ and a constant nitrogen flow rate.
dose rate which was about 1 kGy h-‘. Control samples were processed the same way except for not being irradiated. The glow curves were obtained for the controls and irradiated samples using a Harshaw system model 2000. A linear heating rate of about 9°C SK’ and a constant nitrogen flow was flushing the measuring cell for all the experiments. Heating ranged from 50 to 300°C and the intensity of the thermoluminescent (TL) emission was measured in units of nano coulombs (nC).
INTRODUCTION
Food preservation by gamma irradiation has been found successful for several food items. Several techniques are currently used for identifying irradiated foodstuffs, among them: electron spin resonance (Wieser and Regulla, 1988) seed germination (Uchiyama et al., 1989) and thermoluminescence (Biigl, 1989, 1990; Delincee et al., 1988; Delincee, 1989; Heide and Biigl, 1988; Sanderson et al., 1989). In view of the widespread irradiation preservation of herbs and spices much interest developed for studying the thermoluminescence of herbs and spices in the local market since most of it is imported. The aim of this study is to establish baseline data on thermoluminescence of control and irradiated herbs and spices locally available such that it becomes possible to set up a program for identification of irradiated herbs and spices.
RESULTS AND DISCUSSION
EXPERIMENTAL
Several types of herbs and spices in different packages were obtained locally and were irradiated with different doses of gamma radiation. A Gammacell 220 (AECL, Canada) irradiator loaded with 6oCo was used. Several samples from each type of herb or spice were used in the experiments and the samples were irradiated with doses varying from few kGy to 10 kGy. Ten mg samples were used for the glow curves. The samples were placed in discs cut from 0.5 mm aluminum sheet such that they fit the heater planchette. The doses were given at almost the same 203
All irradiated herbs and spices gave TL emissions above that for the controls in varying degrees. The intensities of the TL varied for the different herbs and spices for the same doses. For the same herb or spice, the TL signal was usually somewhat proportionate to the doses received. The glow curves peaked at about 150°C for most samples. The TL signals from ginger, cinnamon, thyme, turmeric, paprika, cumin, rosemary and some black pepper samples (Figs 1, 3, 4, 5, 7, 8, 9, 13 and 14) were relatively less intense than those from sweet paprika, chili and some black pepper varieties (Figs 2, 6, 10, 11 and 12). Furthermore some packaged samples of black pepper gave TL signals very different in intensities as shown in Figs 10, 11 and 12, for the same doses. Sanderson et al. (1989) investigated the origins of the TL signals from herbs and spices and has shown that they are due to usually very low levels of inorganic matter. The differences in the intensities of TL signals from different herbs and spices reported in the present work could be due to differences in the nature and amounts of dust or inorganic materials
204
A. MAMOON er al.
1O-l
v
C *
10
Paprika
=
3
0
u C 303
5
2
w .!I +
20-
f4 w
2
.: I-
lo-
2 2
1
6 :: 0 0
3
3; u-l
%
4
Cumin
8-
u C
2 g
,ISweet
40-
*-
;: S “: -I t-
50
Ginger
iq6i 0
0
0
400
200
TEM!?I*C
TEt.lPI°C
Fig. 1.
Fig. 2.
3
4
1
h 0
20
40
TEMP.
I°C
Fig. 3.
15Chili
Turmeric
1 0 0 TEMF!
/ OC
TEMP.1
Fig. 4.
Of
1
0
I
200
200 TEMP.
“C
Fig. 5.
I
4 IO 1°C
Fig. 6.
.I
4(
260
TEMl?I°C
TEMP.
Fig. 7
Fig. 8. Figs l-9
(legend opposile)
Fig. 9.
’ I ‘C
4 IO
Thermoluminescence
of irradiated
20s
herbs and spices
80.
Black
Pepper
260 TEMP.
I OC
IEMP.
: OC
Fig. 1 I.
Fig. 10.
Fig. l-l I. Typical glow curves obtained at different doses for some irradiated rate was 9°C SK’ and they dose rate approximately 1 kGy h-‘. Curve I: control; 3: dose 6 kGy.
adhering to the samples of herbs and spices. This could be due, perhaps, to differences in the nature of the soils supporting these herbs and spices, in addition to variations in implementing hygienic conditions in their collection from the fields. The degree of contamination with dusts and other inorganic material can apparently vary even for samples of the same type of spice but obtained from different packages or containers, as shown for the case of black pepper samples given the same dose (Figs 10 and 11). The fading of the TL signal vs time was tested by irradiating two black pepper samples from the same container with same doses. The TL signal from one sample was obtained shortly after end of irradiation
herbs and spices. Heating curve 2: dose 3 kGy; curve
(Fig. 13) while the other sample was stored at room temperature and a TL signal was obtained from it after about nine months (Fig. 14). It can be seen that there was little fading in the signal with time although there appears to be some broadening of the TL signal. The slow fading of the TL signal, was even more pronounced when the TL signal was obtained from separated inorganic material from irradiated spice, as was reported by (Gbksu-ijgelman and Regulla, 1989). A half life for the TL signal in this latter case was determined to be about 5 years at room temperature.
Black
Pepper
200
0 400 Fig. 12. Typical glow curves obtained at different doses for some irradiated herbs and spices. Heating rate was 9 C SK’ and the y dose rate approximately I kGy h- ‘. Curve : control; curve 2: dose 6 kGy; curve 3: dose IO kGy.
200
400
TEMPIV Fig. 13. Typical glow curves obtained at different doses for some irradiated herbs and spices. Heating rate was 9°C s-’ and the ;’ dose rate approximately 1 kGy h-‘. Curve I: control; curve 2: dose I kGy; curve 3: dose 2 kGy: curve 4: dose 3 kGy; curve 5: dose 4 kGy.
A. MAMOON et al.
206
2.c Black
Pepper
Acknowledgemenrs~The authors wish to thank Zaheer, Mr S. Abu-Abdullah, Mr S. Wajed and Sharif for their help with parts of this work.
Dr A. Mr H.
REFERENCES
” z z In E w I -1 *
1.5
BogI K. W. (1989) Identification of irradiated foods methods, developments and concepts. Inl. J. Appl. Radial. losrop. 40,
l.C
0.5
Fig. 14. Typical glow curves obtained at different doses for some irradiated herbs and spices; similar irradiated sample as that in Fig. 13 but the glow curve was obtained after 9
months post-irradiation. Heating rate was 9°C s-’ and the 7 dose rate approximately 1kGy h- ‘. Curve 1: control; curve 2: dose 1kGy; curve 3: dose 2 kGy; curve 4: dose 3 kGy; curve 5: dose 4 kGy.
BogI K. food. Delincee fying
1203- 1210.
W. (1990) Methods
for identification of irradiated 35, 301-3 IO. H. (1989) Luminescence measurements for identiirradiated spcies and herbs. Int. Work.~hop on Food Irradiafion, Hsinchu, Taiwan, pp. I18 127. Delincee H., Ehlermann D. A. E. and BogI K. W. (1988) The feasibility of an identification of radiation processed food. In Healrh Impact, Idenr(jicarion and Dosimerry o/ Irradiated Foods. Report of a WHO Working Group, Bericht des Instituts fur Strahlenhygiene des BundesgeISH- 125. Neuherberg, pp. 58 127. sundheitsamtes, Germany. Goksu-Cjgelman H. Y. and Regulla D. F. (1989) Detection of irradiated food. Narure 340, 23. Heide L. and BogI K. W. (1988) Thermoluminescence and chemiluminescence measurements as routine methods for the identification of irradiated spices. In Health Impacf. Idenrification, and Dosimetry qf Irrudiured Foods. Report of a WHO Working Group, Bericht des Instituts fur Strahlenhygiene des Bundesgesundheitsamtes ISH- 125. Neuherberg, pp. 2077232. Sanderson D. C. W.. Slater C. and Cairns K. .I. (1989) Thermoluminescence of foods: origins and implications for detecting irradiation. Rudiur. Phys. Chem. 34, Radial.
Php.
Chrm.
915924.
It can be concluded from the experiments carried out that identification of irradiated herbs and spices can be done in most cases. However, since apparently both the dose received and the nature and amount of contaminating inorganic material, affect the intensity of the signal, assessment of the dose received from only the TL signal obtained from the whole spice can be subject to error.
Uchiyama S.. Konno S., Toyooka M., Kawamura Y. and Saito J. (1989) Studies of identification of gammairradiation grapefruit by germination method. J. Food H_vg. SW. Jap. 30, 152~ 159. Wieser A. and Regulla D. F. (1988) Identification of irradiated spices by ESR spectroscopy. In Hrullh Impuct. Idenr#icufion and Dosimefrv of’ Irrudiutcd Foods. Report of a WHO Working Group. Bericht des Instituts fur Strahlenhygiene des Bundesgesundheitsamtes ISH-125. Neuherberg, pp. I5 I I6 I.