Inorganic elements in sugar samples

2013 International Nuclear Atlantic Conference - INAC 2013

Recife, PE, Brazil, November 24-29, 2013

ASSOCIAÇÃO BRASILEIRA DE ENERGIA NUCLEAR - ABEN

ISBN: 978-85-99141-05-2

INORGANIC ELEMENTS IN SUGAR SAMPLES

Paula M. B. de Salles

, Maria Ângela de B. C. Menezes

e Tarcísio P. R. de Campos

Universidade Federal de Minas Gerais (UFMG), Departamento de Engenharia Nuclear (DEN)

* Pós-graduação em Ciências e Técnicas Nucleares

Av. Presidente Antônio Carlos nº 6627

31270-901 Belo Horizonte, MG

pauladesalles@yahoo.com.br, tprcampos@pq.cnpq.br

Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN)

Av. Presidente Antônio Carlos nº 6627, CEP 31270-901

Caixa Postal 941, CEP 30161-970, Belo Horizonte, MG, Brazil

menezes@cdtn.br

ABSTRACT

Sugar is considered a safe food ingredient; however, it can be contaminated by organic elements since its

planting until its production process. Thus, this study aims at checking the presence of inorganic elements in

samples of crystal, refined and brown sugar available for consumption in Brazil. The applied technique was

neutron activation analysis, the k

method, using the TRIGA MARK I IPR-R1 reactor located at CDTN/CNEN,

in Belo Horizonte. It was identified the presence of elements such as, Au, Br, Co, Cr, Hf, K, Na, Sb, Sc and Zn

in the samples of crystal/refined sugar and the presence of As, Au, Br, Ca, Co, Cr, Cs, Fe, Hf, K, Na, Sb, Sc, Sm,

Sr, Th and Zn in the brown sugar samples. The applied technique was appropriate to this study because it was

not necessary to put the samples in solution, essential condition in order to apply other techniques, avoiding

contaminations and sample losses, besides allowing a multi elementary detection in different sugar samples.

1. INTRODUCTION

Sugar is defined as a white sweet carbohydrate, while pure, and mainly obtained by sugar

cane. Commercially, the word “sugar” refers to saccharose [1, 2]. However, there is a great

variety of sugars which are derived from many kinds of vegetables and are produced from

different methods. Sugar cane has been produced in big quantities in tropical regions for

many centuries and still dominates the world supply of this product. On the other hand, beet

sugar is a recent culture that became to be consumed in the 19th century in temperate regions

[1, 3].

Sugar comes from cane and is obtained through stalk milling and grinding. The extracted

juice is treated in order to remove impurities and after that it is concentrated by boiling to

form thick syrup. The crystallized sugar is separated from the syrup by rotation in a

centrifuge and the obtained product is called raw sugar. After the refining process of such raw

product it is obtained the white crystal sugar which is known in the commerce [2, 4].

Sugar is classified as a safe category of food. O açúcar é reconhecidamente classificado como

um ingrediente alimentar seguro. However, it can be considered a product that had several

procedures which involved chemical products, contact with equipments and stocking,

bagging, packing and distribution, which can contain several contaminants [5], compromising

the food safety of the product. From the point of view of health, one of the aspects that hasn’t

INAC 2013, Recife, PE, Brazil.

been studied so deeply is the presence of inorganic contaminants, which due to the prolonged

consumption of sugar, can compromise the individual’s health, acting also as a source of

exposition to other elements ca occur in several levels in the environment [6, 7, 8].

Most of the vegetables species that grow on the soil, mainly the polluted ones, absorb metals

[9]. The accumulation of traces of metals, metaloids and other inorganic elements in

agricultural soils has a big interest due to food safety and big risks to human health as well as

to other soil ecosystems [10].

The presence of inorganic elements in sugars can occur in function of natural factors related

to the vegetable planting as for example, the geographic location of the planting, kind of soil,

content of the drainage of the waters and sort of planting in the cultivated in the surrounding

areas [11, 12]. However, the antropic activities as the soil intervention for the development of

agricultural activities, the mineral exploration, solid waste and the industrial processes have a

significant contribution to the contamination of the natural ecosystems [13, 14, 15].

The inorganic constituents of sugar cane occur in the form of ions, salts, integrants of organic

molecular complexes, or as insoluble compounds. The main cations are K, element that is

present in more quantity (60% of the ashes present in the bouillon), Ca, Fe, Al, Na, Mg, Mn,

Cu, Zn and B. Among the onions, the phosphates, chlorates, sulphates, nitrates, silicates and

oxalates are highlighted [16, 17].

The toxic effects of elements such as, As, Cd, Hg and Ni in human health have been

described. These elements have a wide aspect of toxicity that includes neurotoxic effects,

hepatoxic, teratogenic, nephrotoxic, and mutagenic effects, among others, [18, 19, 20, 20, 21,

22, 23, 24, 25] and they can be related to the emergence of cancer [19, 20, 26, 27, 28, 29]. In

this sense, this study aims at identifying the presence of inorganic elements in samples of

crystal, refined and brown sugar commercialized in Brazil.

2. METHOD

2.1 Samples collecting

For the present study, samples of crystal, refined and brown sugar were obtained by using

bags of 3 to 5 g available in restaurants, snack shops and pubs. However, it is not known the

place where the sugar was produced or even the cultivation raw material. Likewise, crystal

and refined sugar were grouped in the same category due to the absence of specification in

their labels in function of their refining process.

2.2 Analysis of the Samples

The samples were analyzed from application of the k

method of neutronic activation, k

INAA, using the reactor TRIGA MARK I IPR-R1 located at CDTN/CNEN, in Belo

Horizonte. The procedure for the irradiation was constituted of the packaging of the samples,

irradiation, gamma spectrometry and determination of the elementary concentrations. As an

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internal control, samples of certified references were analyzed, one of geological material

(soil), IAEA/Soil 7, and anther of biological material (plant, tea), GBW 0805, Tea leaves.

For the analysis, they had their masses measured in polyethylene tubes appropriated to

irradiation and with usual dimensions to apply the technique. The time for the irradiation of 8

hours was enough to activate the isotopes with nuclear characteristics adequate to determine

the elements whose radionuclides showed medium half- lives (for example, As, Au, Br, Ga,

K, La, Na and Sm), and log lives (for example, Fe, Sb, Sc, Sr and Zn).

After each irradiation, it was expected an adequate time in order to have the decay of the

radionuclides with shorter half-lives so that they could interfere in the gamma spectrometry.

In the gamma detection system, composed of a gamma detector HPGe with electronics

associated and the programm of spectra acquisition Genie 2000, CANBERRA, the gamma

spectra were raised by a necessary time so that they could reach a good counting statistics.

The gamma spectra evaluation was carried out with the programm HyperLab [30, 31] and the

elementary concentrations were calculated by the program Kayzero for Windows.

INAC 2013, Recife, PE, Brazil.

3. RESULTS AND DISCUSSION

Table 1 shows the results of the samples of certified reference. It is observed an agreement

between the experimental and the certified values.

Table 1: Materials of Reference: experimental and certified results

Elements

GBW 0805 (Tea leaves)

IAEA/Soil7

Certified

Values

(mg kg

-1

)

Experimental

Values

(mg kg

-1

)

Certified

Values

(mg kg

-1

)

Experimental

Values

(mg kg

-1

)

0.191 ± 0.03

0.199 ± 0.017

13.4 ± 0.85

13.2 ± 0.5

15.7 ± 2.04

14.8 ± 1.2

159*

149 ± 9

2840 ± 227.20

3134 ± 195

163000*

165900 ± 6400

0.686 ± 0.09604

0.74 ± 0.04

61 ± 6.50

59 ± 2

< 1

8.9 ± 0.85

9.0 ± 0.5

< 0.1

60 ± 12.50

62 ± 3

< 0.1

5.4 ± 0.75

5.3 ± 0.2

373.0 ± 26.11

399 ± 14

25700*

26750 ± 930

< 1

5.1 ± 0.35

4.8 ± 0.2

19700 ± 1379.00

20860 ± 733

12100*

12190 ± 480

0.458 ± 0.0229

0.44 ± 0.02

28 ± 1.00

28 ± 1

142 ± 14.20

159 ± 6

2400*

2422 ± 22

< 2

30 ± 6

28 ± 1

36.9 ± 1.476

39 ± 1

51 ± 4.50

49 ± 4

0.037 ± 0.00333

0.042 ± 0.002

1.7 ± 0.20

1.6 ± 0.1

< 0.01

8.3 ± 1.05

8.7 ± 0.3

< 1

5.1 ± 0.35

4.90± 0.03

10.8 ± 1.84

12.4 ± 0.9

< 50

< 0.1

0.8 ± 0.2

0.8 ± 0.1

< 0.2

0.6 ± 0.2

0.63± 0.03

0.105 ± 0.0126

0.114 ± 0.004

8.2 ± 1.05

7.8 ± 0.3

< 0.1

2.6 ± 0.55

2.1 ± 0.2

< 0.1

2.4 ± 0.35

2.3 ± 0.1

38.7 ± 3.87

38 ± 3

104 ± 6.0

108 ± 5

NR, not reported; *, informative value.

In relation to the experimental data, the presence of the elements Au, Br, Co, Cr, Hf, K, Na,

Sb, Sc and Zn was observed in the samples of crystal/refined sugar. In the brown sugar, the

elements As, Au, Br, Ca, Co, Cr, Cs, Fe, Hf, K, Na, Sb, Sc, Sm, Sr, Th and Zn were detected.

(Table 2).

As the brown sugar doesn’t undergo the process of crystallization or refining, it is possible

that calcium, iron, and mineral salt [32] be kept in the final product. The brown sugar has as a

characteristic its production, usually handmade, to which procedures of broth purification as

well as separation or drying of the sugar isn’t used. There isn’t the defined crystal anymore,

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but light brown sugar granules which are made from all soluble components of the broth of

sugar cane [33]. Next results from the macro and microscopic researches show that samples

of brown sugar can contain strange bodies from the failures of the processing associated to

wrong manipulation, problems with the installations and inadequate stocking of the raw

material [34]. It can justify the big quantity of inorganic elements detected in its composition.

Table 2: Inorganic elements present in the analysed sugar samples

The results of the analyses showed the presence, in the sugar samples, of elements like Au,

Ce, Cs, Hf, La, Sc, Sm and Th, which are not present in the list of essential elements for the

human beings and also that are extremely toxic because they tend to link to the sites which

contain sulfur, such as the group sulphydryl (-SH) to proteins for being soft metals [35, 36].

This trend increases the possibility of risk to health mainly if there is a big period of

Elements

Refined Sugar

(mg kg

-1

)

Brown Sugar

(mg kg

-1

)

< 0,01

0,29 - 0,01

0,00018 - 0,00003

0,0006 - 0,0001

< 1

1,2 - 0,1

0,009 - 0,001

2,7 - 0,1

< 150

1726 - 283

< 0,1

< 0,05

0,048 - 0,005

0,007 - 0,001

0,037 - 0,001

0,03 - 0,01

0,70 - 0,03

< 0,005

0,0067 - 0,0004

2,6 - 0,4

43 - 2

0,011 - 0,001

0,0080 - 0,0005

< 0,01

5,9 - 0,2

5044 - 177

< 0,02

0,019 - 0,001

3 - 1

10,5 - 0,4

< 0,1

< 0,2

< 0,02

0,008 - 0,001

0,0083 - 0,0005

0,0002 - 0,0001

0,0036 - 0,0001

< 0,02

< 0,0002

3,2 -0,3

< 100

< 2

3,2 - 0,3

< 0,004

0,0039 - 0,0004

26 - 1

29 - 1

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exposition/ingestion of such elements. The presence of Sb, of the same period of As, which is

not essential as well, can be a big risk to health.

4. CONCLUSIONS

The applied technique, neutron activation analysis, k

method, was appropriate for the study,

because it was not necessary to put the samples in solution, essential condition in order to

apply other techniques to avoid the contamination and the loss of the samples. The

determination of several elements without being necessary the standard of elements – relative

method – made the analysis more efficient.

It was observed the presence of the elements Au, Br, Co, Cr, Hf, K, Na, Sb, Sc and Zn, in

both kinds of sugar which were analyzed and whose origin is Brazilian (refined/crystal and

brown).

Many times the consumed brown sugar is thought to be a natural product, with less quantity

of contaminants. However, the fact that it doesn’t undergo industrial processes to which the

crystal and refined sugars are submitted, the brown sugar keeps a bigger variety of

contaminants in its composition. Thus, it was the sugar that showed a bigger variability of

detectable chemical elements, such as, As, Au, Br, Ca, Co, Cr, Cs, Fe, Hf, K, Na, Sb, Sc, Sm,

Sr, Th and Zn.

ACKNOWLEDGMENTS

The authors thank to CAPES/CNPq for their support to the research project and to

CDTN/CNEN.

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