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: elsa.vasco@insa.min-saude.pt)

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