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Научни трудове на Съюза на учените в България - Пловдив. Серия В. Техника и технологии, т. XIV, ISSN 1311-9419 (Print), ISSN 2534-9384 (On- line), 2017. Scientific Works of the Union of Scientists in Bulgaria-Plovdiv, series C. Technics and Technologies, Vol. XIV., ISSN 1311-9419 (Print), ISSN 2534-9384 (On- line), 2017.
ИЗСЛЕДВАНИЯ НА pb И zn В КИСЕЛО МЛЯКО BRANDS В РЕПУБЛИКА КОСОВО АгЬёг Hyseni1, Milaim Sadiku1, Dilaver Salihu1, Ismet Mulliqi1,
Lorikë Salihu2 1. Университет на Митровица «Isa Boletini», Факултет по Хранителни Технологии, Косово. 2. Магистър Студент Химикотехнологичен и Металургичен Yниверситет, София, България.
RESEARCH OF PB AND ZN IN YOGURT BRANDS IN REPUBLIC OF KOSOVO Arbër Hyseni1, Milaim Sadiku1, Dilaver Salihu1, Ismet Mulliqi1, Lorikë Salihu2 1. University of Mitrovica "Isa Boletini", Faculty of Food Technology, Kosovo. 2. Master Student University of Chemical Technology and Metallurgy,
Sofia, Bulgaria.
Abstract
The aim of this article was to research the concentration of lead and zinc in 10 locally manufactured and imported yogurt brands in the Republic of Kosovo. Heavy metal concentrations were determined using flame atomic absorption spectrometry after dry ashing in electric programming muffle furnace through gradual increase of temperature until it reached 450D. Concentrations of lead in yogurt brands were found in the range 0.003 - 0.0067 mg/kg whereas for zinc in the range 0.087 - 0.137 mg/kg. According to this scientific research all products are safe to consume regarding lead and zinc concentrations.
Keywords: lead, zinc, yogurt
Introduction
Heavy metal research was done in locally manufactured and imported yogurt brands. In total 10 different yogurt brands were researched for lead and zinc concentrations. Heavy metals are chemical elements with heavy atomic mass, some of them are essential for humans and other creatures in low amount like Zn, whereas their shortage can cause disorders in normal body functions. Exceeded limits of these heavy metals in organism especially for Pb represents a poisoning with many different consequences, from problems with late development of children to chronic disease from long time exposure. Heavy metal concentrations research in different yogurt brands presents an important aspect concerning safety of these products for human consumption.
Methodology
Samplemassforanalysis was 10g yogurt. After well homogemzed these sampees were putted for dry ashing in electric programming muffle furnace through gradual increase of temperature untilit reached450 □. Io obtrnnedash 5nfl 6M were yddeVandatid wasevaporated cymWdtely ma loeut plate.
ResidueswAredessalved le tOml OdMioid Seito stand forS So 2htoveredwith watch glass. Solution was stirred in crucible thoroughly and content was transferred to plastic bottle. Concenttations were determined using flame atomic absorption spectrometry. (Jorhem, 2000).
Results
ao S
0,008 0,007 0,006 0,005 0,004 0,003 0,002 0, 001 0
I I I
I I
a-
V
Figure 1 . Lead concentration inyogurts
CP
0,16 0,14 0,12 0,1 0,08
o0,060 0,04
0,02 0,
6
4 > 1 llll .■III 1 ■ ■ ■ 1 1 ■ ■
1 1 1 1 1 1 1 1 1 1 1 1 I 1 I 1 1 1 1 1 1 1 1 1
Figure 2. Zinc concentration in yogurts
Discussion of results
Results of analysis for locally manufactured products show a concentration of lead in yogurts in range 0,003 - 0,0067 mg/kg whereas for imported yogurts in range 0,0049 - 0,0069 mg/kg. Maximum allowed limit for lead in raw milk, thermally treated and which is used for production of milk based products is 0,020 mg/kg (EC, 2006), while for yogurt no EU regulation was found. Results for imported and locally manufactured yogurt brands don't exceed maximum allowed level for milk 0,020 mg/kg and results are graphically shown in figure 1. Approximate levels were reported in a scientific research for yogurt brands in markets of Rumania with values form 0,00706 - 0 ,01277 mg/kg done by ICP-MS. (Prioteasa, 2014).
Zinc concentrations in locally manufactured yogurts are in range 0,087 - 0,137 mg/kg whereas for imported yogurt brands in range 0,0863 - 0,117 mg/kg. Maximum allowed level for zinc in milk according to IDF is 0,328 mg/kg (El Sayed, 2011), and regulations for yogurt lacks they will be compared with milk limit. Results for imported and locally manufactured yogurt brands don't exceed maximum allowed level for milk 0,328 mg/kg and results are graphically shown in figure 2. In separate scientific researches done before zinc in yogurt was found in levels form 0,456 - 1,309 mg/kg (Prioteasa, 2014), but also in higher level 4,51 mg/kg.
(Tarakgi, 2013).
Conclusion
Lead and zinc as seen from results are almost unavoidable in yogurts. Zinc is essential in low amounts for organisms whereas lead is highly toxic metal. However concentration of these heavy metals in researched products don't exceed maximum allowed level. All researched products are safe to consume regarding heavy metal concentrations.
References
[1]. Jorhem, L. (2000). Determination of metals in foods by atomic absorption spectrometry after dry ashing: NMKL collaborative study. Journal of AOAC International, 83(5), 1204-1211.
[2]. EC. (2006). Commission regulation (EC) no. 1881/2006 of 19 December 2006 setting maximum levels for certain contaminants in foodstuffs. Official Journal of the European Union, L364, 5-24.
[3]. Prioteasa, L., Prodana, M. "Evaluation of heavy metals and toxic elements content in time in bio and non-bio yogurts by icp-ms method", U.P.B. Sci. Bull., Series B, Vol. 76, Iss. 3, 2014.
[4]. Elham M. El Sayed, Ahmed M. Hamed, Sanna M. Badran, Amr A. Mostafa "A survey of selected essential and heavy metals in milk from different regions of Egypt using ICP-AES " Food Additives & Contaminants: Part B Vol.4, Iss. 4, 2011.
[5]. Tarakgi, Z. Dag, B. "Mineral and heavy metal by inductively coupled plasma optical emission spectrometer in traditional Turkish yogurts", Vol. 8(19), pp. 963-966, 23 May, 2013.
Authors
*. Corresponding author, Arber Hyseni, Master of Science in Food Engineering and Technology, University of Mitrovica "Isa Boletini", Mitrovice, Kosovo, mobile +386 (0) 49 665988; e-mail [email protected].
M. Sadiku, D. Salihu, I. Mulliqi, Faculty of Food Technology, University of Mitrovica "Isa Boletini", Mitrovice, Kosovo.
. L.Salihu, Master Student in University of Chemical Technology and Metallurgy, Sofia, Bulgaria
