Thermal processing of foods can lead to the formation of acrylamide, a carcinogen. Acrylamide forms as a result of the Maillard reaction between the amino acid asparagine and reducing sugars in foods during high temperature processes like baking, frying and roasting. The document discusses the mechanisms of acrylamide formation, its toxicity, levels found in various foods, regulations and mitigation strategies. Preventive measures discussed include selecting low-sugar and low-asparagine crop varieties, blanching, adjusting processing time and temperature, using acid solutions and antioxidants to inhibit acrylamide formation.

1. ED73.9002: Processing
Effects on the functional
components of food
Acrylamide: Thermal
Process induced
Toxicant
By-
Yakindra Prasad Timilsena
(111332)
Jyotsna Shrestha Khanal 1
(111328)

2. Presentation Outline
• Introduction
• Mechanisms of formation
• Toxicology
• Amounts in different food sources
• Regulations & allowable limits
• Methods of Determination
• Preventive measures
• Conclusion
2

3. Less tasty side to these culinary delights:
Thermally induced harmful chemicals
(Carcinogens)
3

4. What is
Acrylamide ?
• Synthesized for the first time in 1949
• Unsaturated & highly reactive amide
• White odorless crystalline solid, soluble in
water, ethanol, ether, and chloroform
• Formation: baking, roasting, toasting,
grilling, frying
• Common foods: French fries, potato chips,
bread,biscuits, coffee, roasted cereals

5. Properties of Acryl amide
S.N. Properties Values
1. IUPAC name Prop-2 enamide
2. Molecular formula C3H5NO
3. MW 71.08 g mol−1
4. Density 1.13 g/cm3
5. Melting point 84.5 C
6. Solubility in water 2.04 kg/L (at 25 °C)
7. Color white crystalline solid
8. Boiling point 136 °C 5

6. Acrylamide in industrial use
• 1950s: Synthetic Polyacrylamide-based
flocculants
• 1960s: Synthetic coagulants in mineral processing
industries
• 2002: Swedish researchers announced the
discovery of acrylamide in food
PAM 6

7. Acrylamide production in foods
Concentrations AA Formed by Factors (temp.,
& availability of Maillard reaction heat intensity,
Precursor between asparagine water activity)
molecules and reducing sugars in processing
(precursors) technologies
Cereals, potato & coffee : variety and growing factors
Cereals : reducing sugars are abundant → conc. Of
Asparagine →AA
Potato : asparagine is abundant →conc. of reducing sugar→
AA 7

8. Impact of Potato variety on AA Levels
(Source: D. Mottram, U. Reading)
Sample Acrylamide SNFA result
concentration (µg/kg) (µg/kg)
LC-MS-MS
GC-MS
Baking potatoes
raw <10 Nd <30
Boiled <10 Nd
Chipped & fried 310 350
King Edward potatoes Acrylamide formation
raw <10 Nd influenced by
<30
boiled <10 Nd starting raw material
Chipped & fried 2800 3500
Frozen frying chips
as sold 200 100
Cooked 3500 3500
Over cooked 12800 12000 8

9. Heat
Acryl
amide
formation
Carbonyl L-Asparagine
source source
• Removing or changing one of the parameter
prevents formation.
9

10. Mechanism for formation
From Asparagine and Reducing sugar
OH OH
HO
H2N NH2
O
C – CH2 – CH +
OH OH
O COOH
Asparagine Glucose
H2N N
C – CH2 – CH
O COOH
10

11. Mechanism for formation
From Asparagine and Reducing sugar
H2N N
C – CH2 – CH Maillard reaction
O Products
COOH
- CO2
H2N
H2N N
C – CH = CH2
C – CH2 – CH2 O
O Acrylamide
11

12. Mechanism for formation
From Triglycerides
Triglycerides
Heat, O2
Acrylic acid
Acrolein
NH3
Acrylamide
12

13. Variation in concentration of Acrylamide
with temperature and time
1400
1200
Acrylamide (ppm)
1000
800
2.5 min
600 3.5 min
400
200
0
165 170 175 180 185 190
Temperature (0C)
Source: Gertz and Klosterman (2002) Eur. J. Lipid Sci. Technol. 104:762-771. 13

14. AA Formation as a function of Temperature
Potato chips
20000 Frying time: 15 minutes
(0.07930*(Temp-383))
AA = 442.3 * e
15000
Acrylamide (ppb)
5000 100000
380 400 420 440
Temperature (Kelvin) 14

15. Effect of pH on Acrylamide Formation
30000
25000
20000
AA (ppb)
120 C, 40 min
15000
150 C, 15 min
10000
5000
0
4 5 6 7 8 9
pH
15

16. Effect of browning in AA formation
(Source: D. Mottram, U. Reading)
Sample Acrylamide SNFA result
concentration (µg/kg) (µg/kg)
GC-MS LC-MS-MS
Baking potatoes
raw <10 nd <30
Boiled <10 nd
Chipped & fried 310 350
King Edward potatoes Yield of acrylamide
raw <10 Nd increases
<30
boiled <10 Nd substantially with
Chipped & fried 2800 3500 browning
Frozen frying chips
as sold 200 100
Cooked 3500 3500
16
Over cooked 12800 12000

17. Amount of Acrylamide in Foods (ppm)
Category European Data FDA Data
Breads 12-3200 <10-364
Crispbread <30-1670
Crackers and Biscuits <30-2000 26-504
Cereal <30-2300 52-266
Other Grains <30
Potato Chips 150-1280 117-2762
Other Salty Snacks 122-416 12-1168
French Fries 85-1104 20-1325
Other Potato Products <20-12400
Other Veg and Fruit
Products 10-<50 <10-70 17

18. Amount of Acrylamide in Foods (ppm)
Category European Data FDA Data
Meats < 30-64 < 10-116
Candy and Dessert items < 20-110 < 10-909
Cookies 36-199
Coffee and Tea 170-700 175-351
Other Nonalcoholic Beverages < 30
Alcoholic Beverages 30
Dairy Products 10-100 < 10-43
Baby Food and Formula 40-120 < 10-130
Dry Soup Mixes < 10-1184
Gravy and Seasonings 38-54 18

19. Asparagine !!!
Amino Acids Level of Acrylamide Formation
Alanine <50 ppb
Asparagine 9270 ppb
Aspartic Acid <50 ppb
Cysteine <50 ppb
Glutamine 156 ppb
Lysine <50 ppb
Methionine <50 ppb
Threonine <50 ppb
19
Source : Barbara Petersen, Exponent, Inc. October 2002 JIFSAN workshop

20. Stability of acrylamide in various foodstuffs
Food product Interval Acrylamide level (µg/kg)
(month) Initial Second
Breakfast cereal 12 238 238
Soluble coffee powder 12 771 256
Roasted barley 9 265 225
Roasted coffee 7 203 147
Dried chicory 5 214 174
Roasted chicory 5 4015 3395
Cocoa 3 180 177
Chocolate with almond 2 94 73
Soluble chocolate powder 1 54 41
20
Adapted from Delatour et al.

21. Asparagine in Various Crops
• Cheese 40 – 300 mg/100gm
• Asparagus 5.4 – 108 mg/100gm
• Cocoa (raw) 30.9 mg/100gm
- roasted @ 1250C 14.5 mg/100gm
- roasted @ 1350C 9.4 mg/100gm
• Potato 500 – 1000 mg/100gm
• Rye 0.2 – 2.8 mg/100gm
• Wheat 0.2 – 20 mg/100gm
• Corn 0.6 – 1 mg/100gm
Source: Ellin Doyle, Ph.D., Food Research Inst., U. Wisc.
21

22. Toxicology
• Known neurotoxicant (IARC 2002; Manson et al. 2005)
– Peripheral neuropathy
– Tingling/numbness of extremities
– Loss of reflexes
– Chronic CNS dysfunction and neuropathy
• Reproductive toxicity
• Animal carcinogen (CNS, endocrine organs)
• EPA has classified acrylamide as a B2 carcinogen
(probable human carcinogen) (IRIS2009).
• Biomarker – adducts on amino acid valine of Hb.
22

23. Maximum allowable dose level (MADL
•2 micrograms per kg body weight
per day
(Office of Environmental Health Hazard Assessment)
• Exposure at a level 1,000 times greater than the MADL is
expected to have no observable effect
• No Observed Adverse Effect Level (NOAEL) of 15 mg/kg
bw/day were identified in mice
• Legislation under formulation
23

24. • Water extraction
• Analysis by GC-MS with or w/o
bromination
• by LC-MS/MS
• by LC-MS or -UV after deriv. with
mercaptobenzoic acid
• GC-Ion Trap MS
24

25. Acryl amide extracted with water, test
GC-MS portion homogenized, acidified to pH 4-5
method
Addition of Carrez I and Carrez II solution
Extraction with Ethylacetate hexane (80:20),
Filtration over Na2SO4
Clean up with Flourisil elution of
acrylamide with acetone
Evaporation, residue taken up in
ethylacetate, triethylamine added
Filtration, injection into GC-MS 25

26. Acrylamide Precursors – Where to
Intervene
Asparagine Reducing Sugars
- Glucose
- Fructose
- Sucrose hydrolysis?
• Factors affecting asparagine and reducing sugars
- Variety of potato
- Storage conditions

27. Acrylamide Possible Mitigation Strategies
1. Reduction or removal of sugars.
 Selection of low sugar cultivar.
 Blanching and soaking to leach out sugars.
2. Reduction or removal of asparagines.
 Use of enzymes to degrade asparagine during food
processing.
 Blanching to leach out asparagine
3. Processing Conditions
 Altering time-temperature of processing.
 Altering heat processing methods
 Changing pH of food by using acids
 Use of antioxidants
27

28. Reduction of Acrylamide
formation in Potatoes products
• Improve agronomic practices
• Select potatoes variety with less asparagine
• Store potatoes tubers >10 C
• Blanching (82 C)
• Add antioxidants
• Dip slices in citric acid (0.75%) solution
• Dip in NaCl, CaCl2 solution
• Use of enzyme- asparaginase
• Addition of amino acids glycine.
28

29. Reduction of Acrylamide
in cereal products
• Adjustment of time and temperature during
baking.
• Extend fermentation times where feasible.
• Substitution of ammonium bicarbonate with
alternatives
• Avoid or minimize use of reducing sugars
• Avoidance of very high baking temperature
• Use of asparaginase in dough to degrade
asparagine.
29

30. Enzyme mechanism
30

31. Impact of treating with Asparaginase
• By treating with asparaginase there was a
99% reduction in the levels of
acrylamide in the potato mixture
• Product characteristics fully preserved
• No change in process parameters
• Commercially viable and available ???

32. Relative Exposure to Acrylamide in U.S. Food
30
25
French Fries &
20 Potatoes
Coffee
Cakes
15 Breads Dried Foods
Pop Corn
10 Potato Chips Salty Snacks
Cereal Chocolate Products
Biscuit / Cookies Nuts/Seeds/Butters
5
All Other Foods
0
µg/day 32

33. Conclusion
• Acrylamide formation in thermally
processed foods is a major challenges for
bakery, French fries and chip producing
industries.
• challenges still remain in terms of the needs
to develop simple and rapid test methods.
• different pre-frying treatments on the
reduction of acrylamide (AA) formation are
under investigation 33

34. What about these cereal based foods ?
Selroti Puri
Chapati Doughnut 34

35. “Foods should not be cooked
excessively...for too long or at too
high a temperature... However, all
food…should be cooked thoroughly
to destroy food borne pathogens.”
Is it possible to cook food without
forming at least some AA ?????
35