The Hidden Table Salt in Synthetic Food Coloring Materials

Abdalla A Abdalla; Miza A Kombo; Abdul AJ Mohamed*

Department of Natural Science, School of Natural and Social Sciences, the State University of Zanzibar, Tanzania

*Corresponding author: Abdul AJ Mohamed, Department of Natural Science, School of Natural and Social Sciences, the State University of Zanzibar. P. O. Box 146, Zanzibar – Tanzania. Email: jumabdull@yahoo.com

Received: November 05, 2024; Accepted: November 26, 2024; Published: December 03, 2024

Abstract

The purpose of the research was to investigate the presence of hidden table salt (sodium chloride, NaCl) in seven synthetic food colors (saffron yellow, apple green, lemon yellow, orange red, tomato red, raspberry red 1, and raspberry red 2) commonly used in Zanzibar. The samples were collected from Mwanakwerekwe and Darajani Zanzibar. The analysis involved sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), aluminium (Al), and chloride (Cl) in food colors which were analyzed by an Energy Dispersive X-Ray Fluorescence (EDXRF) technique with a Rigaku NEX CG EDXRF model spectrometer. The concentrations of elements in food colouring material were then compared with Food and Agriculture Organization/World Health Organization (FAO/WHO) safe limits. Remarkably, the levels of Na in all samples were higher than safe limits. The maximum detected levels of K, Mg and Ca were also higher than safe limits. Nevertheless, the standard safe limits of Al and Cl are currently not yet in the list of FAO neither in WHO. The percentage composition of Na, Cl, Ca, Mg, K, and Al are found to be 59.1%, 37.6%, 1.0%, 1.0%, 0.7% and 0.7% respectively. Thus the study suggests that a large proportion of food color is in the form of sodium and chloride, which signifies the elemental composition of the table salt (NaCl) which serves as the base in the food coloring matter. The high concentrations of sodium and chloride should be noted precautiously for the consumers with dietary salt restrictions. Excessive intake of sodium could trigger major risks for high blood pressure, which in turn associated with several health complications including an increased risk of cardiovascular diseases such as heart disease and stroke.

Keywords: Table salt; Food color; Dietary sodium; High blood pressure; Stroke

Introduction

Food coloring materials are extensively utilized in the food industry to enhance the visual appeal of products, making them more attractive to consumers [1]. These additives are primarily valued for their ability to impart vibrant colors, thereby increasing the marketability of various food items [2]. However, beyond their intended function, food colorants may contain several elements that are not immediately apparent, raising concern about their potential impact on public health [3]. Among these hidden components, sodium chloride, commonly known as table salt, is particularly noteworthy due to its association with various health risks [4]. Yet sodium and chloride are not the only elements presents in these additives, other elements including K, Mg, and Rb. Ca, strontium (Sr), Al, iron (Fe), silicon (Si), phosphorous (P), sulphur (S) and many others may also found in varying concentrations [5]. The presence of sodium chloride in food colorants is of particular concern given the established link between excessive sodium intake and the presence of hypertension, cardiovascular diseases and other related health conditions [5]. Sodium helps regulate fluid balance in the body, although consuming too much sodium make the body to retain more water in order to balance sodium levels in the blood stream, this in turn increases the volume of blood leading to higher pressure on blood vessel walls, which raises blood pressure [10].

The chronic hypertension caused by high sodium intake increases the risk of cardiovascular diseases, including heart attack, stroke and heart failure [11]. In many regions, dietary salt consumption already exceeds recommended levels, and the unrecognized contribution of food colorants to overall sodium intake could exacerbate this public health issue [6].

Furthermore, the presence of other elements such as heavy metals like uranium and essential minerals like calcium, iron and zinc in these colorants adds an additional layer of complexity [7]. While essential minerals are necessary for maintaining bodily functions, their presence in unregulated amounts can lead to imbalances and interfere with metabolic processes [8]. On the other hand heavy metals are toxic even at low concentrations and pose the long-term health consequences [9].

This study aims to comprehensively investigate the presence and concentration of sodium chloride alongside the four other elements K, Mg, Ca, and Al in various food coloring materials that are commonly used in Zanzibar. Ultimately, this study is aiming at contributing to the broader discourse on food safety and public health by providing actionable insights that can help mitigate the risks associated with the use of food colorants.

Materials and Methods

Sampling

Seven samples of food coloring were meticulously gathered from different vendors operating within Zanzibar's bustling Mwanakwerekwe and Darajani Markets, each sample exclusively in powder form. These samples encompassed a spectrum of vibrant hues: saffron yellow, apple green, lemon yellow, orange red, tomato red, raspberry red 1, and raspberry red 2. Notably, six of these samples were distinctively branded products, reflecting a variety of commercial sources and likely differing in formulation and origin. In contrast, one sample stood unbranded, potentially indicating a local or less widely recognized source within the market landscape. This diverse collection provides a snapshot of the availability and diversity of food coloring options within these vibrant market places.

Labeling of Samples

After gathering these seven samples from two distinct markets, they were transported to the Chemical and Environmental Laboratory at the Africa Minerals and Geosciences Centre (AMGC) in Tanzania for chemical analysis. Each sample was carefully labeled to facilitate clear interpretation of the test results, following the labeling scheme outlined in the table 1.

Table 1: Labelling of Food Colour in Samples.




  
    Serial No
    Food Coloring    Sample
    Codes
  
  
    1
    Apple Green
    AG
  
  
    2
    Raspberry Red1
    RR1
  
  
    3
    Lemon Yellow
    LY
  
  
    4
    Orange Red
    OR
  
  
    5
    Raspberry Red2
    RR2
  
  
    6
    Saffron Yellow
    SY
  
  
    7
    Tomato Red
    TR



Table 1: Labelling of Food Colour in Samples.

Table 2: Concentration of Elements in Food Coloring Samples.




  
    Sample
    Element    Conc. (mg/Kg)
  
  
    Na
    K
    Mg
    Ca
    Al
    Cl
  
  
    AG
    135000
    700
    2800
    1300
    1400
    97600
  
  
    RR1
    177000
    300
    BDL
    1000
    1900
    133000
  
  
    LY
    188000
    1000
    3800
    2400
    2100
    15300
  
  
    OR
    157000
    6400
    2300
    2400
    1900
    127000
  
  
    RR2
    178000
    400
    3000
    4900
    2100
    162000
  
  
    SY
    165000
    2100
    1700
    2900
    1800
    122000
  
  
    TR
    179000
    4500
    2200
    5900
    2300
    144000
  
  
    BDL: Below Detection Limit



Table 2: Concentration of Elements in Food Coloring Samples.

Descriptive Statistics of the Results

The general summary for descriptive statistics were shown in the Table 3.

Table 3: Descriptive Statistics of the Results.




  
    Element
    Min

      conc.
    Max conc.
    Mean
    WHO Standard
    Reference
  
  
    Na
    135000
    188000
    168428.57
    250
    Rasheed et al. 2020 [12]
  
  
    K
    300
    6400
    2200.00
    3500
    Nantel and Tontisirin 2001    [13]
  
  
    Mg
    BDL
    3800
    2257.14
    400
    Puscion-Jackubik et al. 2021 [14]
  
  
    Ca
    1000
    5900
    2971.43
    1300
    Nantel and Tontisirin 2001    [13]
  
  
    Al
    1400
    2300
    1928.57
    NF
    NF
  
  
    Cl
    15300
    162000
    114414.29
    NF
    NF
  
  
    NF: Not Found



Table 3: Descriptive Statistics of the Results.

The data presents the concentrations of various elements found in a sample, alongside their respective WHO standards and references. Sodium (Na) levels range from 135,000 to 188,000 mg/kg with a mean of 168,429 mg/kg, which is significantly above the WHO standard of 250 mg/kg. Potassium (K) concentrations span from 300 to 6,400 mg/ kg, averaging 2,200 mg/kg, which is below the WHO standard of 3,500 mg/kg. Magnesium (Mg) ranges from below detection limit (BDL) to 3,800 mg/kg, with a mean of 2,257 mg/kg, surpassing the WHO standard of 400 mg/kg. Calcium (Ca) varies from 1,000 to 5,900 mg/ kg, with an average of 2,971 mg/kg, which is below the WHO standard of 1,300 mg/kg. Aluminum (Al) levels range from 1,400 to 2,300 mg/ kg, averaging 1,928.57 mg/kg, with no WHO standard available. Iron (Fe) concentrations range from 28 to 75 mg/kg with a mean of 50.14 mg/kg, surpassing the WHO standard of 19.6 mg/kg. Chlorine (Cl) concentrations range from 15,300 to 162,000 mg/kg, averaging 114,414.29 mg/kg, with no WHO standard provided. Overall, many of the measured elements exceed the WHO standards, particularly sodium, magnesium, and potassium, which could indicate potential concerns regarding their levels in the sample (Table 3).

Chronological Order of Elements Levels in Analyzed Food Colors

The actual trend of Na, K, Mg, Ca, Al and Cl concentration in decreasing order as observed in seven food coloring samples are summarized in Table 4.

Table 4: Trend of Na, K, Mg, Ca, Al and Cl in Food Colors.




  
    Element
    Trend    of Metal Composition in Descending Order
  
  
    Na
    LY > TR > RR2 > RR1 > SY > OR > AG
  
  
    K
    OR> TR > SY > LY > AG > RR1 > RR2
  
  
    Ca
    TR > RR2 > SY >LY = OR >AG > RR1
  
  
    Mg
    LY > RR2 >AG > OR >TR > SY > RR1
  
  
    Al
    TR > LY = RR2 > RR1 = OR > SY > AG
  
  
    Cl
    RR2 > TR > RR1 > OR > SY > AG > LY



Table 4: Trend of Na, K, Mg, Ca, Al and Cl in Food Colors.

Percentage Composition of Analyzed Elements

The table 5 presents the percentage composition of each element for all samples analyzed.

Table 5: The percentage composition of each element in food colors.




  
    Sample
    Percentage composition of element (%)
  
  
    Na
    K
    Mg
    Ca
    Al
    Cl
  
  
    AG
    56.5
    0.2
    1.2
    0.5
    0.6
    40.9
  
  
    RR1
    56.5
    0.1
    BDL
    0.3
    0.6
    42.5
  
  
    LY
    88.4
    0.5
    1.8
    1.1
    1.0
    7.2
  
  
    OR
    52.9
    2.2
    0.8
    0.8
    0.6
    42.8
  
  
    RR2
    50.8
    0.1
    0.9
    1.4
    0.6
    46.2
  
  
    SY
    55.8
    0.7
    0.6
    1.0
    0.6
    41.3
  
  
    TR
    53.0
    1.3
    0.7
    1.7
    0.7
    42.6
  
  
    Average %
    59.1
    0.7
    1.0
    1.0
    0.7
    37.6



Table 5: The percentage composition of each element in food colors.

Na and Cl Levels in Food Colors

Both Sodium and Chloride show high concentrations across all samples, with notable variations. The lowest concentration of sodium was detected in AG whereas the highest concentration was detected in LY, in contrast chloride showing highest concentration in RR1 and lowest concentration in SY as seen in Figure 1.

Figure 1: Level of sodium and chloride in food color samples.

    
    
    Figure 1: Level of sodium and chloride in food color samples.

The presence of sodium and chloride in food colors, is a subject of considerable importance due to their impact on health and product quality. But the presence of high levels of sodium and chloride lead to various health implications. Excessive sodium intake is a major risk factor for hypertension (high blood pressure), which in turn is associated with an increased risk of cardiovascular diseases, including heart disease and stroke. Sodium contributes to fluid retention, leading to edema (swelling) and potentially straining renal function as the kidneys work to excrete the surplus. Long-term consumption of high-sodium foods can exacerbate kidney disease and other related health issues.

On the other hand, Elevated chloride levels can also have health implications, particularly concerning the body's acid-base balance. Chloride, along with sodium, plays a critical role in maintaining this balance; excessive chloride can disrupt this equilibrium, leading to metabolic acidosis. High chloride levels may also contribute to dehydration by altering electrolyte balance, which can affect overall bodily functions and health.

K, Mg, Ca and Al in Food Colors

The analysis of the nutrient data reveals significant variability in mineral concentrations among the food coloring samples. Lemon Yellow stands out with the highest magnesium (3800 mg/Kg) and calcium (2400 mg/Kg) levels, indicating its potential for superior health benefits. In contrast, Raspberry Red1 has no detectable magnesium, which may limit its nutritional value. Orange Red shows the highest potassium content (6400 mg/Kg), which could be advantageous for maintaining electrolyte balance. Meanwhile, Tomato Red and Raspberry Red2 both demonstrate high calcium levels (5900 mg/Kg and 4900 mg/Kg, respectively), suggesting they could contribute to bone health. The presence of aluminum across the samples varies, with Raspberry Red1 containing the most (1900 mg/ Kg) as seen in figure 2.