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CONCLUSIONS The method used in the present work has proved to be suitable for a wide variety of food matrices.
Acknowledgement Study supported by Project MONITADITIVOS (INSA), Portugal.
References[1] C. Lino, A. Pena, Food Chemistry, 2010, 121, 503-508..
[2] EN 12856:1999 - Foodstuffs Determination of acesulfame-k, aspartame and saccharin - High Performance Liquid Chromatographic method XIV Encontro da Química dos Alimentos, Viana do Castelo, Portugal, 6-9 November 2018.
João Costa1, Celeste Serra1, Elsa Vasco2
1Chemical Engineering Department, High Institute of Engineering of Lisbon, LISBOA, Portugal2Food and Nutrition Department, National Health Institute Doutor Ricardo Jorge, IP, LISBOA, Portugal
(e-mail: [email protected])
DETERMINATION OF BENZOIC ACID AND SORBIC ACID
IN FOODSTUFFS BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY WITH UV DETECTION
INTRODUCTION In recent decades, there has been a change in the dietary pattern of the population towards an increase in consumption of more
industrialized foods. With this, food industry has faced many challenges on maintaining the quality and nutritional value of the products and at the same
time increasing the shelf life. Benzoic Acid (BA) and Sorbic Acid (SA), and its salts, are food preservatives responsible for inhibiting microorganism growth
and thus, protecting food products from spoilage. Although these preseratives are recognized by the EFSA and FDA as being safe, there are concerns
arising from their wide occurrence in food, cosmetics and pharmaceutical products, that can lead to an increase of the daily intake and possible risks of
exceeding the acceptable daily intake (ADI)[1]. Therefore, occurrence data are essential to ensure consumer safety through exposure assessment studies.
AIM This study aimed to evaluate the presence of benzoic and sorbic acids in 23 samples of food products commercially available in the market, using a
validated HPLC method with UV detection based on European Standard 12856, and compare their levels with the respective allowable limits.
MATERIALS AND METHODS
The analytical method was based on EN 12856.[2]
HPLC system: Waters 2695 Separations Module equipped with a
sample cooler, a column heater/cooler and a 2996 photodiode
array detector.
Column: PrevailTM C18 (250 x 4.6mm, 5 µm).
Mobile phase: Phosphate buffer (0.0125M, pH 3.5):ACN (95:5
V/V) gradient mode.
Flow Rate: 1 mL/min.
Injection Volume: 20 µL for standards and 10 or 20 µL for
samples.
Detection: λ = 220 nm.
Identification: Based on standard retention time.
23 Samples comprising (soft drinks, dairy products, quince jams, sauces, bakery and pastry products)
Sample homogenization
Sample weight
Sample dissolution and protein and fat extraction with CarrezSolutions
Sample filtration
SAMPLE PREPARATION CHROMATOGRAPHIC CONDITIONS
RESULTS AND DISCUSSION
y = 72859x + 12374
y = 27882x + 101,64
0,0E+00
5,0E+05
1,0E+06
1,5E+06
2,0E+06
2,5E+06
3,0E+06
3,5E+06
0 10 20 30 40
Pe
ak a
rea
Concentration (µg/mL)
Benzoic Acid
Sorbic Acid
Figure 1. Chromatogram of acesulfame K (1), saccharin (2), theobromine
(3), aspartame (4), caffeine (5), benzoic acid (6) and sorbic acid (7).
21
3
5 6
74
• The HPLC method was previously validated and allowed a good resolution for the studied preservatives. Furthermore, this method can also be used for the
determination of sweeteners and alkaloids (Figure 1).
• Both analytes were quantified using external standard method (Figure 2).
Figure 2. Calibration curves for benzoic acid (y=72859x + 12374,
r=0.9999) and sorbic acid (y=27882x + 101.64, r=0.9998).
Figure 3. Levels of benzoic and sorbic acids (in mg L-1) in soft
drinks and dairy products samples and respective MPLs.
• Figures 3, 4 and 5, shows the levels of the food preservatives found in all samples and their comparison with the maximum permited levels (MPL) according to
the present legislation.
Figure 4. Levels of benzoic and sorbic acids (in mg kg-1) in quince
jam samples and respective MPLs.
-25
25
75
125
175
225
275
325
Sa
mp
le 1
Sa
mp
le 2
Sa
mp
le 3
Sa
mp
le 4
Sa
mp
le 5
Sa
mp
le 6
Sa
mp
le 1
5
Sa
mp
le 1
6
Soft Drinks DairyProducts
Concentr
atio
n (
mg L
-1)
Benzoic Acid
Sorbic Acid
300 mg L-1 of BA+SA for dairy products
150+250 mg L-1 of BA+SA for soft drinks
0
200
400
600
800
1000
1200
1400
1600
Sa
mp
le 7
Sa
mp
le 8
Sa
mp
le 9
Sa
mp
le 1
0
Sa
mp
le 1
1
Sa
mp
le 1
2
Quince Jams
Co
nce
ntr
atio
n (
mg
L-1
)
Benzoic Acid
Sorbic Acid
1500 mg kg-1 of BA+SA
Figure 5. Levels of benzoic and sorbic acids (in mg kg-1) in sauces,
bakery and pastry samples and respective MPLs.
• All samples were within the limits imposed by Portuguese legislation.
• Samples 13 and 14, two quince jam, did not report both preservatives on the label, and their absence was confirmed.
• Recovery rates were between 93% and 105% for BA and 93% and 116% for SA at spiked levels of 50% of the MPL.
0
300
600
900
1200
1500
1800
2100
Sa
mp
le 1
7
Sa
mp
le 1
8
Sa
mp
le 2
1
Sa
mp
le 1
9
Sa
mp
le 2
0
Sa
mp
le 2
2
Sa
mp
le 2
3
Emulsified sauce Non-emulsifiedsauce
Bakery Pastry
Concentr
atio
n (
mg L
-1)
Benzoic Acid
Sorbic Acid
2000 mg kg-1 of SA for emulsified sauces and bakery products
1000 mg kg-1 of SA for non-emulsified
sauces
1500 mg kg-1 of SA+BA+Parabens for pastry products