3. FOOD ChEMISTRy & bIOTEChNOLOGy 3.1. Lectures

Chem. Listy, 102, s265–s1311 (2008) Food Chemistry & Biotechnology
L02 APPROAChES TO MINIMIZATION OF
ACRyLAMIDE LEVEL IN FOODS
ZUZAnA CIESAROVá
VÚP Food Research Institute
Priemyselná 4, 824 75 Bratislava, Slovak Republic,
ciesarova@vup.sk
Introduction
Thermal treatment of foods is a common way for improvement
of digestibility, safety, quality and sensory properties
of many foods which is used for ages. Besides unambiguous
desirable aspects of this treatment some detrimental
effects are still emerging e.g. a loss of nutrition-worthy compounds
and an undesirable generation of contaminants.
In 2002, Swedish researchers have first reported the
formation of acrylamide in foods processed at elevated temperatures
1 . Recent assessment by the Joint FAO/WHO Expert
Committee on Food Additives (JECFA) in 2005 2 confirmed
that a risk cannot be excluded for dietary intake of acrylamide
because it is classified as a probable human carcinogen
by the International Agency for Research on Cancer (IARC) 3 .
In that assessment JECFA concluded that the margin of exposure
for average and high consumers were low for compound
that is genotoxic and carcinogenic and that this may indicate
a human health concern. Therefore the Commission Recommendation
since 2007 announced that “appropriate efforts
to reduce acrylamide concentrations in foodstuffs should
continue” 4 . Moreover, with respect to the last observations
confirming the association between acrylamide intake and
endometrial, ovarian 5 , and breast 6 cancer risk, the concern on
the acrylamide mitigation activity is very urgent.
Occurrence of Acrylamide in Thermally Treated Foods
After the discovery of acrylamide, a lot of studies confirmed
the presence of acrylamide in nearly all fried, baked
and roasted foods. Acrylamide exposure varies depending
upon the population´s eating habits and the way the foods
are processed and prepared. Generally, fried potato products,
ready-to-eat breakfast cereals, baked goods and roasted coffee
are the most important food categories that contribute
most to acrylamide exposure. An average long-term exposure
of acrylamide was estimated of 0.3 to 0.8 μg (kg body
weight) –1 day –1 on the base of the few data which were avail-
able at the FAO/WHO Consultation in 2002 7 . Based on the
reported data, the Committee JECFA in 2005 2 noted that
children may have intakes of acrylamide around two or three
times higher those of adult consumers when expressed on a
body weight basis. It is expected that children and adolescents
have consumption patterns different from adults. Most of the
types of foods in which acrylamide was detected are popular
among children and adolescents, such as French fries, snacks,
biscuits and breads. Moreover, they have a lower average
body weight and, consequently, a higher average food intake
per kilogram body weight than adults. For that, acrylamide
intake by these individuals is considered a concern.
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M e c h a n i s m o f A c r y l a m i d e
F o r m a t i o n
Initial results on acrylamide content indicated carbohydrate-rich
foods to generate relatively more acrylamide 1 .
Several researchers have established that the main pathway
of acrylamide formation in foods is linked to the Maillard
reaction and, in particular, the amino acid asparagine 8,9 . The
link of acrylamide to asparagine, which directly provides the
backbone of the acrylamide molecule, has been established by
labelling experiments 9,10 . Study to date clearly shows that the
amino acid asparagine is mainly responsible for acrylamide
formation in heated foods after condensation with reducing
sugars or a carbonyl source. Moreover, the sugar-asparagine
adduct, n-glycosylasparagine, generates high amounts of
acrylamide, suggesting the early Maillard reaction as a major
source of acrylamide 9 . In addition, decarboxylated asparagine
(3-aminopropionamid), when heated can generate acrylamide
in the absence of reducing sugars 10 . A good evidence
supporting the early Maillard rection as a main reaction pathway
involving early decarboxylation of the Schiff base, rearrangement
to the resulting Amadori product, and subsequent
beta-elimination to release acrylamide has been presented 11 .
Factors Affecting Acrylamide Formation in Foods
The resulting acrylamide concentration in foods ultimately
depends on both products and process variables.
Acrylamide formation requires the amino acid asparagine
and a carbonyl compound as the Maillard reaction precursors.
The concentration of acrylamide precursors and temperature
mainly affect the rate of acrylamide formation. It is a fact that
formation and degradation of acrylamide occurs in the same
time during heating at elevated temperatures, it means that
measured acrylamide content of a food is net result of two
consecutive reactions occurred during thermal processing12 .
Based on the current knowledge of the mechanism of
acrylamide formation, many parameters affecting the level
of acrylamide in foods were investigated, e.g. heat intake, the
level and type of saccharides and amino acids, moisture and
water activity, additives, processing steps etc. 13 , and consequently
various ways of acrylamide minimization in foods
have been proposed. Many of them are summarized in a “living”
document “The Acrylamide Toolbox” published by experts
associated in the Confederation of the Food and Drink
Industries of the European Union (CIAA) 14 .
The mitigation approach is divided in two strategies:
Prevention of acrylamide formation through a modification
of food composition (a decline of asparagine
and reducing saccharides contents), processing conditions
(thermal input, pH, moisture), an addition of compounds
suppressing the formation of acrylamide (acids,
enzymes, proteins, antioxidants etc.) and an enhancement
of processing steps (pre-treatment, blanching, fermentation
etc.) 15 .
Facilitation the acrylamide elimination through storage
conditions or the initialization of acrylamide polymerization16,17
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