Food and Environment Safety - Journal of Faculty of Food Engineering, tefan cel MareUniversity - Suceava
Volume XI, Issue 1 – 2012
108
STU DY R EG AR DI NG THE INFLU ENC E OF ME TA LS M IG RA TION
UPON THE QUALITY OF BEER AT STORAGE
*Amelia BUCULEI1, Sonia AMARIEI1, Stefan STEFANOV2, Gheorhe GUTT1,
Adriana DABIJA1
1Stefan cel Mare University, Faculty of Food Engineering, 13th University Street, 720229,Suceava – Romania,
e-mail : ameliab@fia.usv.ro, gutts@fia.usv.ro, g.gutt@fia.usv.ro, dadianadabija@yahoo.com
2 University of Food Technologies, Plovdiv, Bulgaria, stvstefanov@yahoo.com
*Corresponding author
Received 12 February 2012, accepted 7 March 2012
Abstract: For some substances maximum rates of concentration in food and beverages are set.
Essential for consumer safety is to study the mechanisms of metal migration in packaging products.
Very often, sources of migration are elements of the packaging and this pays scant attention.
The aim of this work was to determine the content of heavy metals form different kinds of beer from
market and to observe: pH of the beer at different periods of time and different temperatures of
storage, beer sensorial analysis at different periods of time and different temperatures of storage,
physical-chemical properties of beer at different periods of time and different temperatures of storage.
We studied four types of beer for the content of certain metals as Fe, Cu, Cd, Pb, Al and Mn. The test
was made at 4°C (for cold beer) and at 20°C for the beer in the shop. For purposes of this study used
modern methods and equipment were used. They allow to determine with accuracy the content of
various substances in food and beverages.
The results of experimental work showed increased content of various metals. This is the result of
migration, which is different for different beers tested. During the preservation period of products in
metallic packages, lead and cadmium migration from the packaging material into product takes place
with a rate directly proportional with increasing of storage time. The data obtained allow
determining the conditions under which drinks are safe for consumers.
Key words: heavy metals, migration, beer, aluminium can storage
1. Introduction
The stability of the system food product/
package when food products are preserved
in metallic packages is determined by more
factors among which the migration of
compounds from package into the product
preserved holds an important role.
Metallic containers (cans) are often used
for food, and in particular for beverage
packaging [1]. Most of the beer cans and
refreshments are made of aluminium. In
comparison with the steel the aluminium
and the recipients made of it are lighter
more resistant to corrosion easier to mould
less resistant in general and more
expensive.
All the aluminium recipients have lacquer
systems that prevent very well the contact
between the food and the metal. In this
way all the aluminium levels are generally
very low but occasionally they can affect
the sensitivity of the products such as beer
causing a change of their colour.
The problem of aluminium in beer has
been elaborated in several papers over the
last decade. However, the effect of
aluminium on organoleptic properties of
beer has been observed in few papers
where it has been stated that aluminium
gives beer a »metallic« and bitter flavour
mailto:ameliab:@fia.usv.ro
mailto:gutts:@fia.usv.ro
mailto:g.gutt:@fia.usv.ro
mailto:dadianadabija:@yahoo.com
Food and Environment Safety - Journal of Faculty of Food Engineering, tefan cel MareUniversity - Suceava
Volume XI, Issue 1 – 2012
109
without any observations on particular
aroma compound changes.
Also, the number of reports on precise
changes of aroma components throughout
different storage conditions is surprisingly
scarce. [2]
Furthermore, after filling maturated beer
into bottles, kegs or cans this process goes
on, especially in aluminium cans and kegs.
The process of aluminium corrosion and
migration from can to beer has been
elaborated over the last decade in several
papers. The factors of the main influence
are: the type and quality of cans, the type
and thickness of protective can coating, pH
of the beer, the length of contact between
the can and the beer, thermal treatment,
storage temperature, and presence of any
corrosive substances[3].
Although it is well known that dissolved
oxygen concentration has decisive
influence on beer stability, primary
packaging material can facilitate various
processes with negative influence on
colloidal and/or flavour stability of beer.
Beer filled in glass bottles is sensitive to
light-struck flavour formation [4]. Canned
beer is protected from the influence of
light, but aluminium migration from can to
beer could aggravate colloidal and flavour
stability [5].
Steel beverage can fabrication consists of
DWI process, organic application and
seaming operation. The seaming operation
consists of the junction of body can with
the end (can closing). They are widely
used as containers of various kinds of
beverage. The body of a two-piece can is
formed by a draw and wall ironing (DWI)
process [1–3]. Overlaying tin on the base
steel (tinplate) consists the basic material
more used to make food can to conditioner
food [4,5].
During end seaming operation, organic
discontinuity can be formed at the body
hook and at the end hook (internal seam
area) caused by small frictions. In the
packaging internally lacquered, the
interaction product/packing occurs mainly
through these discontinuities.
The main consequence of this
discontinuity is the iron, which can be
dissolved in the food. The reactions
involved can modify the flavour
characteristic of the product conferring to
it metallic flavour. The combination of
sensory, nutritional and hygienic
characteristics will provide the quality of a
food product [6]. For the case of the
beverage cans made from tinplate, the
control of the migration of iron acquires an
even greater importance, because
extremely small levels of iron migrated to
the drink (0.5 ppm) can already
compromise the flavour of the drink [7].
The lacquer coating is the most widely
used method for reducing tinplate can
corrosion [8-10]. A need for rapid
development of new internal coatings on
tinplate cans arise in the food and beverage
industry, mainly as a response to proposed
volatile organic compound regulations
[11].
The pressure control is important in
achieving the optimal level of carbon
gasification of the product and avoiding
the excessive creation of foam that leads to
the loss of liquid and high air levels in the
recipient (affecting the internal corrosion
and degrading the quality of the product).
If these technological factors are
respected there shouldn’t appear in beer
any organoleptic or physical-chemical
modification when being stored at different
temperatures and periods of time [12].
2. Materials and methods
For experiments it was used blonde beer
samples on a lot taken from the market.
Analyses were conducted periodically
throughout six months of storage on for
different brands of beer (A, B, C and D
brand). Brand A was standard lager beer
and brands B, C and D were premium
lager beers. Samples were stored in a
Food and Environment Safety - Journal of Faculty of Food Engineering, tefan cel MareUniversity - Suceava
Volume XI, Issue 1 – 2012
110
refrigerator (4 °C) or in a thermostatic
chamber (22°C).
For estimate beer’s quality there was made
the following methods:
- total acidity determination- the titration
method in the presence of
phenolphthalein as indicator;
- sensorial analysis- the marking scale
method;
- color of beer – observing of view
comparison of the analyzed sample’s
color with the iodine solution’s color
having a known concentration;
- foam stability – using the times
measuring for the persistent foam,
starting from the moment when the
beer touches the tasting glass till to its
total vanishes;
- CO2 determination – standard method;
- heavy metals content. Prior to heavy
metals concentration determination, 40
ml of beer were withdrawn from cans.
Containers and laboratory materials
were washed with warm, diluted nitric
acid and subsequently rinsed with
double distilled water
(conductivity=0.055 mS/cm). Beer
sample was placed in ultrasonic water
bath to eliminate carbonation(60 min.
at 45Hz, T=20 C, P=100%) and then 5
ml of degassed beer were diluted to 50
ml with 1 % nitric acid (in double
distilled water). After wards, the
sample was placed in the auto sampler
cup and shortly of ICP-MS AGILENT
SERIA 7500ce.
3. Results and discussion
3.1. The sensorial analysis- the marking
scale method
The results of the appreciations led by the
tasting committee members were written in
the tasting papers for each sample of beer
can presented and then the average
percentage was calculated.
On the basis of the average total mark the
evaluation of the quality level of beer can
samples was led taking on account the
organoleptic point of view respectively the
place in the quality levels on the 0-20 scale
as shown in table 1.
Table 1.
The evaluation of the quality level of the beer can samples analyzed
Samples’ name Total average mark Mark Product characterization
Sample A, B, C, D - initially Verygood
The beer can has positive organoleptic traits
specific and well determined.
Sample A
1 month 16,5
Good
The beer can has positive organoleptic traits
specific and well determined but it presents
insignificant taste of heavy metals.3months 16,3
6 months 16
Sample B
Satisfac
tory
The beer can has organoleptic traits slightly
determined and it presents …due to which the
product is situated under the standard admitted
level for the product.
1 month 15,5
3 months 14,5
6 months 12,5
Sample C
Very
good
The bear can has positive organoleptic traits
specific and well determined.
1 month 17
3 months 16,5
6 months
16 Good
The beer can has positive organoleptic traits
specific and well determined but it presents
insignificant taste of heavy metals.
Sample D
Good
The beer can has positive organoleptic traits
specific and well determined but it presents
insignificant taste of heavy metals.
1 month 15,5
3 months 15
6 months 14,5
Food and Environment Safety - Journal of Faculty of Food Engineering, tefan cel MareUniversity - Suceava
Volume XI, Issue 1 – 2012
111
3.2 Physical-chemical analysis
Foam checking. One of the quality
characteristics of the beer appreciated by many
consumers is the height of the foam when
pouring the liquid into the glass and its
persistence. The results of the determinations
led are presented in table 3.
Table 3 .
Checking the foam for the superior beer grades analyzed
Sample Storage time
Foam checking
Height of the foam layer
[mm]
Foam stability
[minutes]
Sample A 1 month 72 15
3 months 60 12
6 months 45 5
Sample B 1 month 65 15
3 months 62 10
6 months 55 5
Sample C 1 month 70 15
3 months 64 13
6 months 48 8
Sample D 1 month 72 15
3 months 68 11
6 months 52 7
Table 4.
The physical-chemical properties of the beer at different periods of time and different temperatures of storage
Sample Storage time (months)
Acidity
[ml Na OH/100mL
beer]
Co2
[g/cm3]
Colour
[EBC units]
at 4°C 22°C at 4°C 22°C at 4°C 22°C
Sample A 1 month 1.8 1.9 0.42 0.46 9.6 9.6
3 months 2.1 2.2 0.48 0.50 9.8 9.8
6 months 2.9 3.2 0.52 0.56 9.9 10.2
Sample B 1 month 2.4 2.8 0.68 0.70 10.7 11
3 months 2.5 3.1 0.72 0.74 10.8 11.7
6 months 2.9 3.3 0.76 0.78 11.3 12.7
Sample C 1 month 1.9 2.1 0.48 0.51 8.8 9.6
3 months 2.3 2.4 0.50 0.56 9.8 10.1
6 months 2.6 2.8 0.52 0.60 10.2 10.6
Sample D 1 month 2.6 2.8 0.69 0.74 10.9 11.3
3 months 2.8 3.3 0.71 0.78 11.5 11.9
6 months 2.5 3.6 0.74 0.80 12.3 12.7
3. Heavy metal content
Figure1. Amendment of lead concentration Figure.2. Amendment of cadmium concentration
in the product at 4 and 22 degrees- for beer A in the product at 4 and 22 degrees- for beer A
Food and Environment Safety - Journal of Faculty of Food Engineering, tefan cel MareUniversity - Suceava
Volume XI, Issue 1 – 2012
112
Figure 3. Amendment of lead concentration
in the product at 4 and 22 degrees- for beer B
Figure 4.Amendment of the cadmium
concentration in the product at 4 and 22 degrees-
for beer B
Figure 5. Al content in the product during storage
of 4 types of beer
Figure 6. Mn content in the product during
storage of 4 types of beer
Figure 7 Cu content in the product during storage
of 4 types of beer
Figure 8 Fe content in the product during
storage of 4 types of beer
Figure 9 Comparison of lead in different beers Figure 10 Comparison of cadmium in
different beers
Food and Environment Safety - Journal of Faculty of Food Engineering, tefan cel MareUniversity - Suceava
Volume XI, Issue 1 – 2012
113
4. Conclusion
The results just confirm that heavy metals
concentration in finished beer differs
among samples of different brands and
also among samples of the same brand
because heavy metals in beer is derived
from various raw materials, equipment and
brewing processes. It was assumed that
during upside down storage more
prominent migration could occur due to the
fact that beer is in contact with the edges
of the can body and its lid on which more
corrosion points could arise.
Generally, temperature of storage
influenced heavy metals migration from
can to beer. It is obvious that heavy metals
vessels in contact with beer have to be well
coated to protect the quality of beer.
Analyzed samples showed certain aroma
stability, which was more expressed for
samples stored at 22°C.
Experimental results show that the
contents of various metals in beer for the
duration of storage. Some beers presence
of metals fast rise, which means that any
element of the package contains high
quantity. Particularly disturbing are the
results for the presence of cadmium in beer
B. Rapid increase of its content in the
product means the wrong choice of one of
the elements. With this type of beer is
likely at the end of the storage period to
exceed the maximum rate of heavy metals
from 60 mg/l.
5. References
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packaging: principles and practice. CRC
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(1996) Prog Org Coat 29:159
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