1. INTRODUCTION
Bread is the most consumed and staple food in many countries around the world. It is made from dough of flour such as wheat and barley, and water. It usually contains several ingredients such as table salt, sugars, flavors, and flour improver [1]. Potassium bromate (KBrO3) was commonly used due to its low cost and acts as a slow oxidizing agent and it makes the dough more strength, and more elastic [2]. Many studies have confirmed the deleterious effects of potassium bromate on human health. For example, according to a study done on mice, potassium bromate administration caused impairment in renal and hepatic tissues. It also increased plasma creatinine levels and decreased antioxidant capacity [3]. Another study found that KBrO3 exposed mice had increased lipid peroxidation, protein oxidation, and numerous degenerative changes in the cerebellum tissues [4]. In addition, important vitamins in bread such as thiamine (B1) and Niacin (B3) were destroyed by the effects of KBrO3. Carcinogenic and mutagenic effects of KBrO3 were also confirmed in experimental animals [5]. The Center for Science and Environment (CSE) [6] indicated that some studies found the link of bromate to cancer, so the global scientific expert committees and CSE suggested reducing the allowed limit of use; also, they recommended that KBrO3 should not be used as a flour treatment agent.
Many studies have proofed that potassium may be cause detrimental health effects in humans [7,8], also in the same area (Metropolis Rivers Stat, Nigeria), the concentration of KBrO3 in all samples was above the allowed concentration and the authors advised the consumer of read from the study area the bread conduction may be of harmful for our health [9]. Due to the harmful effects of this substance, many countries, including France, the United Kingdom, and Canada, have removed KBrO3 from the list of acceptable additive substances to flour [10]. However, the maximal permitted dose of KBrO3 in bread in other countries such as Japan, China, and the USA is 10 mg/kg, 50 mg/kg of flour mass, and 0.02 mg/kg, respectively [11], the most studies indicate that potassium bromate in bread concentration was exceeded the acceptable limit of 0.02 μg/g set by FDA, in Delta State, all 15 bread brand samples was contained a higher concentration of KBrO3 than permitted range [12] and the authors sate that this can be very dangerous for the bread consumers in the study area, and in the study in Erbil, the level of KBrO3 was found to be more (6.66 mg/L–67.45 mg/L) than the permissible limit set by FDA [13]. This study aimed to determine the level of KBrO3 in different types of bread in Sulaimani city, Kurdistan-Iraq.
2. MATERIALS AND METHODS
2.1. Collection of Samples
Bread samples were collected during the day (morning and afternoon) from different bakeries and from different locations in Sulaimani city from August 2021 to November 2021. The locations were the city center, Ibrahim-pasha, Ibrahim-Ahmad, Kani-BA, Sarchnar, Tui-Malik, and Family-mall. Thirty bread samples were collected from five main products that are extremely consumed by Kurdish citizens. The bread-type products were bakery bread (Nani frn), white hamburger bread (Samun), white bread known as Kurdish bread (Nani Hawrami), pizza, and brown barley bread.
2.2. Preparation of Samples
Samples were prepared according to a procedure that has been described and used by Abdulla and Hassan [14]. A small part (about 2 cm) in the center of each bread sample was dried in the oven for 72 h at 55°C. After drying, the sample was ground with an electric grinder to a powder. A 2.5 g of the powder were dissolved in 25 ml of distilling water. After centrifuging, the liquid fraction was diluted to 50 ml.
2.3. Standard Preparations
A stock solution of 200 ppm potassium bromate (KBrO3) was prepared by dissolving 0.200 grams of KBrO3 into 1 L of distilling water. The standard series solutions of potassium bromate were prepared from the stock solution at 0, 4, 12, 20, and 40 ppm.
2.4. Method
A 5 ml of standard or sample solution was mixed with 5 ml of 1% KI, 10 ml of 0.1 N HCl, and then completed to 100 ml. The standards and samples were read after 10 min by a single beam UV–visible spectrophotometer APEL-303 at wavelength 420 nm with a calibration curve used for quantification of the samples.
2.5. Data Analysis
Data were entered into a Statistical Package for the Social Sciences “SPSS” version 26 for the storage and statistical analysis. The one-way ANOVA test was applied to test for association between different groups, with P = 0.05 or less considered significant.
3. RESULTS
The results of this study found that all 30 samples from five main types of bread contained different amounts of KBrO3 residues in their products. Sample number 26 (brown barley bread) had the least content of KBrO3 while sample number 21 (pizza dough) had the highest concentration of KBrO3 (Table 1). The calibration curve of this study was shown (Fig. 1).
TABLE 1: Concentrations of potassium bromate (ppm) in all bread samples
Fig. 1. Calibration curve.
In addition, this study has found that the concentrations of KBrO3 were highest in the pizza group and lowest in the brown barley bread group. The means and standard error of all groups with significant differences between each group of bread types are shown in Table 2 and Fig. 2. There were differences in the means of all groups. However, there were no significant differences between Kurdish bread, white bakery bread, and brown barley bread. On the other hand, there was a significant difference between pizza flour, brown barley bread, and Kurdish bread.
TABLE 2: Concentrations of KBrO3 (ppm) in all five groups of bread samples
Fig. 2. Concentrations of KBrO3 (ppm) in all five groups of bread samples. Values are presented as means ± SE (n=6 sample/group).
4. DISCUSSION
This study was carried out to determine the level of potassium bromate (KBrO3) in the bread samples and to find the highest and lowest concentrations of KBrO3 in different types of bread. Thirty samples from five major consumed types of bread were analyzed and KBrO3 was found in all samples. According to the US Food and Drug Agency (FDA), the amount of KBrO3 in bread higher than 0.02 μg/g (0.00002 parts per million) is considered not safe for human consumption [15]. All 30 samples of the present study were having concentrations of KBrO3 higher than the national permitted levels so that none of the bread of all major types in Sulaimani city might be unsafe for human consumption. This is in agreement with a study done in Hawler city, Kurdistan Region of Iraq; they found that the residual bromate level in the analyzed bread samples by spectrophotometer was in the range from 6.66 mg/L to 67.45 mg/L [13]. In addition, a study in Iraq (Baghdad city) found that electrical Samun and loaf had 10 and 0.3 μg/g potassium bromate, respectively. These levels were higher than the permissible level by the US Food and Drug Agency (FDA). They also found the exposed bread industry workers were elevated in chromosomal aberrations (CA), represented by chromatic breaks (CB), micronuclei (MN), and ring chromosome (RC) [16]. Another study in Iraq (Basrah city) found the harmful effects of potassium bromate on both hematological and biochemical parameters in rats. Liver enzymes (A.L.T and A.S.T) were increased and blood parameters (RBC, Hb, WBC, and PCV) were decreased [17]. A recent study which is done in Dhaka city in Bangladesh showed that 67% of collecting samples were had KBrO3 above the permitted level [18]. The present study also found that there were different concentrations of residues of KBrO3 in different types of bread. The concentrations of KBrO3 were highest in the pizza group and lowest in the brown barley bread group. This agrees with a study done in Tunis country. They observed different concentrations of bromate residues in different types of bread. The muffin contained the highest mean concentration of bromate residue as opposed to bread without salt, which had the lowest mean bromate level [6]. Moreover, a study in Nigeria found that 25% of the bread samples were had potassium bromate above the permissible limit allowed by the US Food and Drug Agency (FDA) and explained that these samples are unsafe for human consumption [19].
5. CONCLUSION
The present study concludes that all bread samples from five major bread types had potassium bromate above the permitted levels allowed by the US Food and Drug Agency (FDA). In general, all samples are unsafe for human consumption; however, the riskiest samples that have a greater concentration of potassium bromate were pizza flour and white bakery bread. The Kurdish bread and brown barley bread have a lower concentration of potassium bromate compared to others.