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Multielement analysis in cereals and pulses by k0 instrumental neutron activation analysis
The Science of the Total Environment 253 Ž2000. 75]79
Multielement analysis in cereals and pulses by k 0 instrumental neutron activation analysis T. Balaji a , R.N. Acharyab, A.G.C. Nair b, A.V.R. Reddy b, K.S. Rao a , G.R.K. Naidua,U , S.B. Manohar b b
a Department of Chemistry, Sri Venkateswara Uni¨ ersity, Tirupati-517 502, India Radiochemistry Di¨ ision, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
Received 18 July 1999; accepted 12 January 2000
Abstract The concentrations of some elements in a few varieties of cereals and pulses are determined by Instrumental Neutron Activation Analysis using a single comparator method Ž k 0-standardised NAA method.. A total of 15 elements are measured. The method was validated by analysing the Standard Reference Material ŽSRM-1571. of NIST; the results are within "10% of the reported values for the majority of the elements. The measured concentrations of major and minor elements are analysed in terms of the average intake of mineral content and the role of these elements in terms of the nutritional value. Q 2000 Elsevier Science B.V. All rights reserved. Keywords: Cereals; Pulses; Neutron activation analysis; Elements and recommended dietary allowance
1. Introduction Wheat and paddy are basic cereal food throughout the world and other cereals such as bajra, ragi and jowar are also cultivated and consumed in certain parts of the world. Pulses such as bengal gram, red gram and moong also form
U
Corresponding author. Fax: q91-8574-27499. E-mail address: [email protected] ŽG.R.K. Naidu.
an important part of the diet. The percentage of foodstuff contribution due to grain product is more than 80% ŽFardy et al., 1992.. The cereals and pulses are the main dietary items for supplying trace elements and nutrients. Previous studies are confined to a limited number of elements ŽRajurkar et al., 1990; Cunningham and Anderson, 1992.. Here, we have analysed five varieties of cereals and seven varieties of pulses, which are used in the normal dietary system. This paper presents the results on the mineral content
0048-9697r00r$ - see front matter Q 2000 Elsevier Science B.V. All rights reserved. PII: S 0 0 4 8 - 9 6 9 7 Ž 0 0 . 0 0 3 7 8 - 8
76
T. Balaji et al. r The Science of the Total En¨ ironment 253 (2000) 75]79
of cereals and pulses. The k 0-standardised NAA method is used for multielement analysis. It uses a comparator-like gold instead of multielement standard for arriving at the concentration values ŽDe Corte et al., 1987; De Corte and Simonits, 1989; Acharya et al., 1997.. The main advantage of this method is that the technique is capable of analysing all the elements that are amenable to INAA and does not require a priori knowledge of the constituent elements.
HPGe detector coupled to a PC-based 4K channel analyser in an efficiency calibrated position. The detector system had a resolution of 2.1 keV at 1332 keV. Gamma ray standard 152 Eu was used for efficiency calibration of the detector. Details of the calculation of elemental concentration using k 0-standardised NAA method are given elsewhere ŽDe Corte et al., 1987; Acharya et al., 1995 Acharya et al., 1997..
3. Results and discussion 2. Experimental 2.1. Sample preparations The samples of cereals ŽC1]C5. and pulses ŽP1]P7. were collected from different representative places of Tirupati, AP, India. The samples were washed, dried and then crushed to a homogeneous fine powder by pulverisation. A known amount of gold foil Ž99.999% pure. was dissolved in aqua-regia. It was evaporated to dryness and was made up in 0.1 M HNO3 and this solution was used as a standard. Samples weighing approximately 30]75 mg along with accurately weighed standard gold Ž5]10 mg. were sealed separately in polypropylene tubes. The volume of the comparator and the sample were kept as small as possible to reduce the neutron self shielding during irradiation and gamma attenuation during radioactive assay. 2.2. Irradiation and measurements Irradiation of samples was carried out in E8 position of the swimming pool APSARA reactor at BARC, Trombay, Mumbai. Irradiation time was varied from 5 min to 7 h depending on the half-life of the activation product. The neutron flux in this position was of the order of 10 12 n cmy2 sy1. Orchard Leaf SRM-1571 Ž30]60 mg. was used as a reference standard for the control of the method. The blank levels of elements present in the polypropylene tubes were estimated by irradiating empty polypropylene tubes in separate experiments. Samples were assayed for gamma activity of the activation products using an 80 cm3
The local names and scientific names of the cereals and pulses analysed are given in Table 1. Elemental concentrations for 15 elements measured in cereals and pulses are given in Tables 2 and 3 along with their standard deviation Ž"1 s. from triplicate measurements. Aluminium, Cl, Mg, K, Na and Ca were determined using short irradiation times, whereas Br, Zn, Mn, Co, Fe, La, Sm, Rb and Se required long irradiation times. The accuracy of the method was validated by analysing the Standard Reference Material ŽSRM-1571, Orchard Leaf. of NIST. The majority of the measured concentration of elements are within "10% of the reported values and elements like Zn Žlong lived., Sm and Eu Žlow concentrations . have higher variations ŽSmodis et al., 1990; Ahmed et al., 1994.. The experimental detection limits for Al, Ca, Mg and V are 0.0033, 0.89, 0.48 and 0.0055 mg, respectively. Calcium has an added advantage that the activation product Ž 49 Ca. has an intense gamma-ray energy of 3.08 MeV, which is free from any spectral interference. Calcium concentration in cereals is in the range of 0.048]0.35% and ragi has a high concentration value. The concentration of Mg in cereals is in the range 0.24]0.92% and paddy and bajra showing the maximum levels. Among pulses, the concentration of Ca and Mg ranges from 0.115 to 1.16% and 0.34 to 1.15%, respectively. In both cases the til Ž Sesamum indicum. contains almost the same level of Ca and Mg and is the maximum. The Fe concentration in paddy samples is higher than that reported by Tehrani Ž1987.. The higher concentration of many elements in paddy com-
T. Balaji et al. r The Science of the Total En¨ ironment 253 (2000) 75]79
77
Table 1 Sample description of the cereals ŽC1]C5. and pulses ŽP1]P7. Sample identification
Local name
Scientific name
C1 C2 C3 C4 C5
Wheat Paddy Bajra Ragi Jowar
Triticum aesti¨ un L. Oryza sati¨ a L. Pennisetum typhoides ŽBurm.f. Staff and Hubb. Eleusine coracana ŽL.. Gaertn Sorghum ¨ ulgare Pers
P1 P2 P3 P4 P5 P6 P7
Methi Moong Chanadal Til Chanli Horse Gram Tur Dal
Trigonella foenum graecum L. Phaseolus aureus Roxb. Cicer arietinum L. Sesamum indicum L. Vigna sinensis ŽL.. Hassk Dolichos biflorus L. Cajanus cajan ŽL.. Mill.
pared to the other cereals and pulses may be due to the fact that the sample was analysed along with the husk. Bromine is present in varying amounts in all cereals and pulses. It has been found to be selectively accumulated in plantsrcereals from soil. Bromine concentration in cereals and pulses is dependent upon the soil conditions. Organic matter is known to accumulate Br and its enrichment in the top soil horizons is principally an effect of its precipitation with rain ŽSvetina et al., 1996.. The presence of higher levels of bromine in agricultural products is due
to the application of agricultural chemicals such as methyl bromide used as a fumigant ŽYamada, 1968.. We have compared the Recommended Dietary Allowance ŽRDA. for some of the known major essential elements with that of the values obtained from this work based on an intake of 100 g cereal or pulses per day ŽNRC, Recommended Dietary Allowances, 1989.. The calcium value of 350 mgrday is the highest value and corresponds to the concentration obtained for ragi. Still this value is below the recommended value of 800
Table 2 Elemental concentrations and S.D. values Ž"1 s. of cereals Žin mgrkg unless % is indicated. a Element
Wheat
Paddy
Bajra
Ragi
Jowar
Na Mg% Al Cl% K% Ca% Mn Br Zn Co Fe La Sm Rb
42.3" 2.3 0.24" 0.02 2.6" 0.4 0.170" 0.004 0.48" 0.05 0.017" 0.001 41 " 4 2.6" 0.4 192 " 14 1.3" 0.1 1915 " 98 0.17" 0.03 N.D. N.D.
196 " 13 0.92" 0.03 1802 " 48 0.33" 0.03 0.48" 0.06 0.110" 0.004 152 " 8 2.38" 0.52 93 " 6 0.51" 0.02 817 " 54 0.46" 0.05 0.140" 0.003 166 " 11
85 " 3 0.70" 0.01 995 " 99 0.26" 0.01 0.54" 0.05 0.031" 0.002 32.9" 1.9 0.38" 0.02 154 " 10 0.96" 0.04 467 " 12 N.D. N.D. 115 " 9
115 " 1.4 0.44" 0.03 N.D. 0.106" 0.002 0.58" 0.03 0.35" 0.02 267 " 7 0.97" 0.08 62 " 3 0.37 " 0.02 490 " 21 0.48" 0.06 N.D. 72 " 5
107 " 3.5 0.69" 0.02 887 " 51 0.14" 0.01 0.65" 0.06 0.048" 0.003 19.7" 2.0 1.65" 0.08 77.6" 4.6 2.71" 0.14 1376 " 50 N.D. 0.16" 0.01 N.D.
a
N.D., not detected.
T. Balaji et al. r The Science of the Total En¨ ironment 253 (2000) 75]79
78
Table 3 Elemental concentration and S.D. values Ž"1 s. of pulses Žin mgrkg unless % is indicated. a Elem.
Methi
Moong
Chanadal
Til
Chanli
Horse gram
Tur dal
Na Mg% Al Cl% K% Ca% Mn Br Zn Co Fe Se La Sm Rb
391 " 24 0.87" 0.04 N.D. 0.27" 0.01 1.62" 0.04 0.30" 0.01 20.6" 0.8 0.63" 0.02 167 " 12 3.02" 0.21 1261 " 88 54 " 3 N.D. 0.089" 0.004 204 " 11
27.6" 3.5 0.88" 0.04 N.D. 0.108" 0.001 1.32" 0.03 0.17" 0.01 15.5" 0.4 0.50" 0.01 155 " 10 2.14" 0.11 856 " 25 N.D. N.D. N.D. 83 " 5
168 " 13 0.87" 0.03 650 " 41 0.190" 0.003 1.24" 0.12 0.24" 0.01 31.1" 1.2 13.2" 0.4 87 " 2 0.74" 0.04 1181 " 63 30 " 1 0.17" 0.02 N.D. 77.1" 3.5
231 " 4 1.15" 0.05 778 " 7 0.095" 0.002 0.93" 0.11 1.16" 0.02 22.6" 1.9 5.7" 0.3 83 " 3 1.78" 0.04 935 " 30 28.3" 1.4 0.16" 0.01 0.033" 0.002 126 " 7
149 " 9 0.79" 0.03 1079 " 67 0.064" 0.002 1.91" 0.02 0.40" 0.04 44 " 1 2.27" 0.12 96 " 2 0.45" 0.02 806 " 25 8.77" 0.36 0.25" 0.03 0.08" 0.02 192 " 11
55 " 1 051 " 0.02 586 " 38 0.071" 0.001 1.55" 0.04 0.34" 0.03 49 " 0.9 2.81" 0.24 128 " 8 0.75" 0.05 1466 " 32 N.D. 0.027" 0.001 N.D. N.D.
53 " 6 0.34" 0.02 186 " 11 0.040" 0.002 1.6" 0.2 0.12" 0.01 10.1" 0.6 5.12" 0.25 61 " 2 0.54" 0.02 913 " 35 44 " 5 0.74" 0.03 N.D. 52 " 6
a
N.D., not detected.
mgrday. The determined intake value of Mg for cereals range from 240 to 920 mgrday, whereas for pulses it is in the range of 340]1150 mgrday and these values of Mg are well above the recommended value Ž300 mgrday. except for wheat. The concentration of iron in the majority of the samples is higher than the recommended values by the WHO Ž1987. and NRC Ž1989.. Wheat, bajra, methi, moong and horse gram are rich in Zn. Data for the aluminium content of food items and diet varies with soil type, contamination from aluminium vessels used for cooking and due to its use for various purposes such as water purification, etc. Very small levels of Ca Ž50]400 mgrg. have a protective role against Al toxicity level of 50 mgrkg bodyrday ŽBasu et al., 1997.. Manganese is the only essential element for which no known deficiency has been reported ŽSigel, 1983.. This may be due to the lower requirement compared to the higher level of availability. Manganese availability is observed to be affected by excess dietary Ca. The toxicity of Mn is the lowest of all metals ŽUnderwood, 1977; Reilly, 1980. and a concentration of more than 1000 mgrg intake is required to produce any toxic effects in man. The observations of Fardy et al. Ž1992. in Australia showed that the richest source of Mn are the grain products like cereals and pulses whereas, the dairy and meat products have the lowest Mn
content. The Mn concentration levels reported for cereals and pulses ŽShankar Rao and Deosthale, 1981; Rajurkar et al., 1990. are, in general, in good agreement with the Mn concentrations reported here. Inspite of an adequate supply of Zn and Fe through a cereal-based diet, occurrence of Fe and Zn deficiencies are common in Third World Countries. This is attributed to the decreased bioavailability of the element from a purely cereal-based diet not supplemented with animal protein ŽKyritsis et al., 1997.. The phytate present in the cereals and pulses binds Zn, particularly in the presence of Ca, and reduces the biological availability with the result that the requirements for the element are not satisfied. The adsorption of Fe is greatly affected by several factors, especially the general level Žamount. and chemical form and as well by the various other components of the diet, both organic and inorganic. Ascorbic acid with its high chelating property is found to increase Fe adsorption. Excess Co and Zn are found to influence Fe adsorption. Soil and climatic differences directly affect the elemental content of food items of plant origin. On the other hand bioavailability of elements depends on several etiologic factors, e.g. chemical state, fibre content, the presence of complexing agents accompanying the intake and the extent to which
T. Balaji et al. r The Science of the Total En¨ ironment 253 (2000) 75]79
other interacting elements are present or absent from the diet. Synergetic and antagonistic effects caused by the presence of other elements also influence the bio-availability. Elemental toxicity in man arising from excess intake of food and beverages is not frequently reported unless there is an occurrence of industrialrenvironmental contamination. Analysis of food items not only provides data on nutritional surveillance programmes, but also on the contamination brought in by several indiscriminating activities.
Acknowledgements The authors thank the personnel of APSARA reactor for their co-operation in irradiating the samples. One of the authors ŽTB. thanks the CSIR for financial assistance in the form of Research Associateship. References Acharya RN, Burte PP, Nair AGC, Reddy AVR, Manohar SB, 1995. Reactor neutron activation analysis by single comparator method: k 0 measurements, BARC report, BARCr1995rEr007. Mumbai: BARC. Acharya RN, Burte PP, Nair AGC, Reddy AVR, Manohar SB. Multielement analysis of natural ruby samples by neutron activation using the single comparator method. J Radioanal Nucl Chem 1997;220Ž2.:223. Ahmed S, Waheed S, Mannan A, Fatima I, Qureshi IH. Evaluation of trace elements in wheat and wheat byproducts. J AOAC Int 1994;77Ž1.:11. Basu S, Chaudhuri D, Chaudhur AN. Influence of Ca on the toxic effects of dietary Al. J Food Sci Technol 1997; 34Ž3.:264.
79
Cunningham WC, Anderson DL. Multielement analysis of food and related materials by NAA. Trans Am Nucl Soc 1992;65:141. De Corte F, Simonits A. k 0-measurements and related nuclear data compilation for Ž n, g . reactor neutron activation analysis. IIIb tabulation. J Radioanal Nucl Chem 1989;133Ž1.:43. De Corte F, Simonits A, De Wispelaere A, Hoste J. Accuracy and applicability of the k 0 -standardization method. J Radioanal Nucl Chem 1987;113Ž1.:145. Fardy JJ, Mc Orist GD, Farrar YJ. The determination of Mn status in the Australian diet using neutron activation analysis. J Radioanal Nucl Chem 1992;163Ž2.:195. Kyritsis A, Kanias GD, Tzia C. Nutritional values of trace elements in dried desserts. J Radioanal Nucl Chem 1997;217Ž2.:209. Rajurkar NS, Shah NP, Purushottam J. Simultaneous determination of mineral nutrients in different varieties of wheat and bengalgram in India by INAA. Appl Radiat Isot 1990;41Ž6.:579. NRC, Recommended Dietary Allowances ŽRDA.. 10th ed. Washington, DC: National Research Council, 1989. Reilly C. Metal contamination of food. London: Applied Science Publishers Ltd, 1980:81. Shankar Rao DS, Deosthale YG. Mineral composition of four Indian food legumes. J Food Sci 1981;46:1962. Sigel H. Metals ions in biological systems, vol. 16. New York and Basel: Marcel Dekker INC, 1983. Smodis B, Jacimovic R, Jovanovic S, Stegnar P. Determination of trace elements in standard reference materials by the k 0-standardization method. Biol Trace Elem Res 1990:43. Svetina M, Smodis B, Jacimovic R. Proc 2nd International k 0 users workshop. Ljubljana, Slovenia, 1996:103. Tehrani DK. Trace elements analysis in rice. J Radioanal Nucl Chem Lett 1987;117:133. Underwood EJ. Trace elements in human and animal nutrition. New York: Academica Press, 1977:189. WHO. Trace elements in human nutrition. Technical report series a532, Geneva, 1987. Yamada Y. Occurrence of bromine in plants and soil. Talanta 1968;15:1135.
Multielement analysis in cereals and pulses by k 0 instrumental neutron activation analysis T. Balaji a , R.N. Acharyab, A.G.C. Nair b, A.V.R. Reddy b, K.S. Rao a , G.R.K. Naidua,U , S.B. Manohar b b
a Department of Chemistry, Sri Venkateswara Uni¨ ersity, Tirupati-517 502, India Radiochemistry Di¨ ision, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
Received 18 July 1999; accepted 12 January 2000
Abstract The concentrations of some elements in a few varieties of cereals and pulses are determined by Instrumental Neutron Activation Analysis using a single comparator method Ž k 0-standardised NAA method.. A total of 15 elements are measured. The method was validated by analysing the Standard Reference Material ŽSRM-1571. of NIST; the results are within "10% of the reported values for the majority of the elements. The measured concentrations of major and minor elements are analysed in terms of the average intake of mineral content and the role of these elements in terms of the nutritional value. Q 2000 Elsevier Science B.V. All rights reserved. Keywords: Cereals; Pulses; Neutron activation analysis; Elements and recommended dietary allowance
1. Introduction Wheat and paddy are basic cereal food throughout the world and other cereals such as bajra, ragi and jowar are also cultivated and consumed in certain parts of the world. Pulses such as bengal gram, red gram and moong also form
U
Corresponding author. Fax: q91-8574-27499. E-mail address: [email protected] ŽG.R.K. Naidu.
an important part of the diet. The percentage of foodstuff contribution due to grain product is more than 80% ŽFardy et al., 1992.. The cereals and pulses are the main dietary items for supplying trace elements and nutrients. Previous studies are confined to a limited number of elements ŽRajurkar et al., 1990; Cunningham and Anderson, 1992.. Here, we have analysed five varieties of cereals and seven varieties of pulses, which are used in the normal dietary system. This paper presents the results on the mineral content
0048-9697r00r$ - see front matter Q 2000 Elsevier Science B.V. All rights reserved. PII: S 0 0 4 8 - 9 6 9 7 Ž 0 0 . 0 0 3 7 8 - 8
76
T. Balaji et al. r The Science of the Total En¨ ironment 253 (2000) 75]79
of cereals and pulses. The k 0-standardised NAA method is used for multielement analysis. It uses a comparator-like gold instead of multielement standard for arriving at the concentration values ŽDe Corte et al., 1987; De Corte and Simonits, 1989; Acharya et al., 1997.. The main advantage of this method is that the technique is capable of analysing all the elements that are amenable to INAA and does not require a priori knowledge of the constituent elements.
HPGe detector coupled to a PC-based 4K channel analyser in an efficiency calibrated position. The detector system had a resolution of 2.1 keV at 1332 keV. Gamma ray standard 152 Eu was used for efficiency calibration of the detector. Details of the calculation of elemental concentration using k 0-standardised NAA method are given elsewhere ŽDe Corte et al., 1987; Acharya et al., 1995 Acharya et al., 1997..
3. Results and discussion 2. Experimental 2.1. Sample preparations The samples of cereals ŽC1]C5. and pulses ŽP1]P7. were collected from different representative places of Tirupati, AP, India. The samples were washed, dried and then crushed to a homogeneous fine powder by pulverisation. A known amount of gold foil Ž99.999% pure. was dissolved in aqua-regia. It was evaporated to dryness and was made up in 0.1 M HNO3 and this solution was used as a standard. Samples weighing approximately 30]75 mg along with accurately weighed standard gold Ž5]10 mg. were sealed separately in polypropylene tubes. The volume of the comparator and the sample were kept as small as possible to reduce the neutron self shielding during irradiation and gamma attenuation during radioactive assay. 2.2. Irradiation and measurements Irradiation of samples was carried out in E8 position of the swimming pool APSARA reactor at BARC, Trombay, Mumbai. Irradiation time was varied from 5 min to 7 h depending on the half-life of the activation product. The neutron flux in this position was of the order of 10 12 n cmy2 sy1. Orchard Leaf SRM-1571 Ž30]60 mg. was used as a reference standard for the control of the method. The blank levels of elements present in the polypropylene tubes were estimated by irradiating empty polypropylene tubes in separate experiments. Samples were assayed for gamma activity of the activation products using an 80 cm3
The local names and scientific names of the cereals and pulses analysed are given in Table 1. Elemental concentrations for 15 elements measured in cereals and pulses are given in Tables 2 and 3 along with their standard deviation Ž"1 s. from triplicate measurements. Aluminium, Cl, Mg, K, Na and Ca were determined using short irradiation times, whereas Br, Zn, Mn, Co, Fe, La, Sm, Rb and Se required long irradiation times. The accuracy of the method was validated by analysing the Standard Reference Material ŽSRM-1571, Orchard Leaf. of NIST. The majority of the measured concentration of elements are within "10% of the reported values and elements like Zn Žlong lived., Sm and Eu Žlow concentrations . have higher variations ŽSmodis et al., 1990; Ahmed et al., 1994.. The experimental detection limits for Al, Ca, Mg and V are 0.0033, 0.89, 0.48 and 0.0055 mg, respectively. Calcium has an added advantage that the activation product Ž 49 Ca. has an intense gamma-ray energy of 3.08 MeV, which is free from any spectral interference. Calcium concentration in cereals is in the range of 0.048]0.35% and ragi has a high concentration value. The concentration of Mg in cereals is in the range 0.24]0.92% and paddy and bajra showing the maximum levels. Among pulses, the concentration of Ca and Mg ranges from 0.115 to 1.16% and 0.34 to 1.15%, respectively. In both cases the til Ž Sesamum indicum. contains almost the same level of Ca and Mg and is the maximum. The Fe concentration in paddy samples is higher than that reported by Tehrani Ž1987.. The higher concentration of many elements in paddy com-
T. Balaji et al. r The Science of the Total En¨ ironment 253 (2000) 75]79
77
Table 1 Sample description of the cereals ŽC1]C5. and pulses ŽP1]P7. Sample identification
Local name
Scientific name
C1 C2 C3 C4 C5
Wheat Paddy Bajra Ragi Jowar
Triticum aesti¨ un L. Oryza sati¨ a L. Pennisetum typhoides ŽBurm.f. Staff and Hubb. Eleusine coracana ŽL.. Gaertn Sorghum ¨ ulgare Pers
P1 P2 P3 P4 P5 P6 P7
Methi Moong Chanadal Til Chanli Horse Gram Tur Dal
Trigonella foenum graecum L. Phaseolus aureus Roxb. Cicer arietinum L. Sesamum indicum L. Vigna sinensis ŽL.. Hassk Dolichos biflorus L. Cajanus cajan ŽL.. Mill.
pared to the other cereals and pulses may be due to the fact that the sample was analysed along with the husk. Bromine is present in varying amounts in all cereals and pulses. It has been found to be selectively accumulated in plantsrcereals from soil. Bromine concentration in cereals and pulses is dependent upon the soil conditions. Organic matter is known to accumulate Br and its enrichment in the top soil horizons is principally an effect of its precipitation with rain ŽSvetina et al., 1996.. The presence of higher levels of bromine in agricultural products is due
to the application of agricultural chemicals such as methyl bromide used as a fumigant ŽYamada, 1968.. We have compared the Recommended Dietary Allowance ŽRDA. for some of the known major essential elements with that of the values obtained from this work based on an intake of 100 g cereal or pulses per day ŽNRC, Recommended Dietary Allowances, 1989.. The calcium value of 350 mgrday is the highest value and corresponds to the concentration obtained for ragi. Still this value is below the recommended value of 800
Table 2 Elemental concentrations and S.D. values Ž"1 s. of cereals Žin mgrkg unless % is indicated. a Element
Wheat
Paddy
Bajra
Ragi
Jowar
Na Mg% Al Cl% K% Ca% Mn Br Zn Co Fe La Sm Rb
42.3" 2.3 0.24" 0.02 2.6" 0.4 0.170" 0.004 0.48" 0.05 0.017" 0.001 41 " 4 2.6" 0.4 192 " 14 1.3" 0.1 1915 " 98 0.17" 0.03 N.D. N.D.
196 " 13 0.92" 0.03 1802 " 48 0.33" 0.03 0.48" 0.06 0.110" 0.004 152 " 8 2.38" 0.52 93 " 6 0.51" 0.02 817 " 54 0.46" 0.05 0.140" 0.003 166 " 11
85 " 3 0.70" 0.01 995 " 99 0.26" 0.01 0.54" 0.05 0.031" 0.002 32.9" 1.9 0.38" 0.02 154 " 10 0.96" 0.04 467 " 12 N.D. N.D. 115 " 9
115 " 1.4 0.44" 0.03 N.D. 0.106" 0.002 0.58" 0.03 0.35" 0.02 267 " 7 0.97" 0.08 62 " 3 0.37 " 0.02 490 " 21 0.48" 0.06 N.D. 72 " 5
107 " 3.5 0.69" 0.02 887 " 51 0.14" 0.01 0.65" 0.06 0.048" 0.003 19.7" 2.0 1.65" 0.08 77.6" 4.6 2.71" 0.14 1376 " 50 N.D. 0.16" 0.01 N.D.
a
N.D., not detected.
T. Balaji et al. r The Science of the Total En¨ ironment 253 (2000) 75]79
78
Table 3 Elemental concentration and S.D. values Ž"1 s. of pulses Žin mgrkg unless % is indicated. a Elem.
Methi
Moong
Chanadal
Til
Chanli
Horse gram
Tur dal
Na Mg% Al Cl% K% Ca% Mn Br Zn Co Fe Se La Sm Rb
391 " 24 0.87" 0.04 N.D. 0.27" 0.01 1.62" 0.04 0.30" 0.01 20.6" 0.8 0.63" 0.02 167 " 12 3.02" 0.21 1261 " 88 54 " 3 N.D. 0.089" 0.004 204 " 11
27.6" 3.5 0.88" 0.04 N.D. 0.108" 0.001 1.32" 0.03 0.17" 0.01 15.5" 0.4 0.50" 0.01 155 " 10 2.14" 0.11 856 " 25 N.D. N.D. N.D. 83 " 5
168 " 13 0.87" 0.03 650 " 41 0.190" 0.003 1.24" 0.12 0.24" 0.01 31.1" 1.2 13.2" 0.4 87 " 2 0.74" 0.04 1181 " 63 30 " 1 0.17" 0.02 N.D. 77.1" 3.5
231 " 4 1.15" 0.05 778 " 7 0.095" 0.002 0.93" 0.11 1.16" 0.02 22.6" 1.9 5.7" 0.3 83 " 3 1.78" 0.04 935 " 30 28.3" 1.4 0.16" 0.01 0.033" 0.002 126 " 7
149 " 9 0.79" 0.03 1079 " 67 0.064" 0.002 1.91" 0.02 0.40" 0.04 44 " 1 2.27" 0.12 96 " 2 0.45" 0.02 806 " 25 8.77" 0.36 0.25" 0.03 0.08" 0.02 192 " 11
55 " 1 051 " 0.02 586 " 38 0.071" 0.001 1.55" 0.04 0.34" 0.03 49 " 0.9 2.81" 0.24 128 " 8 0.75" 0.05 1466 " 32 N.D. 0.027" 0.001 N.D. N.D.
53 " 6 0.34" 0.02 186 " 11 0.040" 0.002 1.6" 0.2 0.12" 0.01 10.1" 0.6 5.12" 0.25 61 " 2 0.54" 0.02 913 " 35 44 " 5 0.74" 0.03 N.D. 52 " 6
a
N.D., not detected.
mgrday. The determined intake value of Mg for cereals range from 240 to 920 mgrday, whereas for pulses it is in the range of 340]1150 mgrday and these values of Mg are well above the recommended value Ž300 mgrday. except for wheat. The concentration of iron in the majority of the samples is higher than the recommended values by the WHO Ž1987. and NRC Ž1989.. Wheat, bajra, methi, moong and horse gram are rich in Zn. Data for the aluminium content of food items and diet varies with soil type, contamination from aluminium vessels used for cooking and due to its use for various purposes such as water purification, etc. Very small levels of Ca Ž50]400 mgrg. have a protective role against Al toxicity level of 50 mgrkg bodyrday ŽBasu et al., 1997.. Manganese is the only essential element for which no known deficiency has been reported ŽSigel, 1983.. This may be due to the lower requirement compared to the higher level of availability. Manganese availability is observed to be affected by excess dietary Ca. The toxicity of Mn is the lowest of all metals ŽUnderwood, 1977; Reilly, 1980. and a concentration of more than 1000 mgrg intake is required to produce any toxic effects in man. The observations of Fardy et al. Ž1992. in Australia showed that the richest source of Mn are the grain products like cereals and pulses whereas, the dairy and meat products have the lowest Mn
content. The Mn concentration levels reported for cereals and pulses ŽShankar Rao and Deosthale, 1981; Rajurkar et al., 1990. are, in general, in good agreement with the Mn concentrations reported here. Inspite of an adequate supply of Zn and Fe through a cereal-based diet, occurrence of Fe and Zn deficiencies are common in Third World Countries. This is attributed to the decreased bioavailability of the element from a purely cereal-based diet not supplemented with animal protein ŽKyritsis et al., 1997.. The phytate present in the cereals and pulses binds Zn, particularly in the presence of Ca, and reduces the biological availability with the result that the requirements for the element are not satisfied. The adsorption of Fe is greatly affected by several factors, especially the general level Žamount. and chemical form and as well by the various other components of the diet, both organic and inorganic. Ascorbic acid with its high chelating property is found to increase Fe adsorption. Excess Co and Zn are found to influence Fe adsorption. Soil and climatic differences directly affect the elemental content of food items of plant origin. On the other hand bioavailability of elements depends on several etiologic factors, e.g. chemical state, fibre content, the presence of complexing agents accompanying the intake and the extent to which
T. Balaji et al. r The Science of the Total En¨ ironment 253 (2000) 75]79
other interacting elements are present or absent from the diet. Synergetic and antagonistic effects caused by the presence of other elements also influence the bio-availability. Elemental toxicity in man arising from excess intake of food and beverages is not frequently reported unless there is an occurrence of industrialrenvironmental contamination. Analysis of food items not only provides data on nutritional surveillance programmes, but also on the contamination brought in by several indiscriminating activities.
Acknowledgements The authors thank the personnel of APSARA reactor for their co-operation in irradiating the samples. One of the authors ŽTB. thanks the CSIR for financial assistance in the form of Research Associateship. References Acharya RN, Burte PP, Nair AGC, Reddy AVR, Manohar SB, 1995. Reactor neutron activation analysis by single comparator method: k 0 measurements, BARC report, BARCr1995rEr007. Mumbai: BARC. Acharya RN, Burte PP, Nair AGC, Reddy AVR, Manohar SB. Multielement analysis of natural ruby samples by neutron activation using the single comparator method. J Radioanal Nucl Chem 1997;220Ž2.:223. Ahmed S, Waheed S, Mannan A, Fatima I, Qureshi IH. Evaluation of trace elements in wheat and wheat byproducts. J AOAC Int 1994;77Ž1.:11. Basu S, Chaudhuri D, Chaudhur AN. Influence of Ca on the toxic effects of dietary Al. J Food Sci Technol 1997; 34Ž3.:264.
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