3. FOOD ChEMISTRy & bIOTEChNOLOGy 3.1. Lectures

Chem. Listy, 102, s265–s1311 (2008) Food Chemistry & Biotechnology
P o t a t o P a n c a k e s P r e p a r a t i o n
Potato-cereal powder for pancakes preparation was
purchased from local market (Bramborák, Amylon, Czech
Republic). Dough was prepared with water (control sample)
and L-asparaginase solution (1 U g –1 ). 4 pancakes with
weight of 35 ± 1 g were fried on teflon pan (Tescoma, Czech
Republic) in one run in microwave MW 800 HW 25 (Orava,
Slovak Republic) using convection programme (170, 185 and
200 °C), 10 min for each side of pancake.
acrylamide (mg.g -1 FW)
5
4
3
2
1
0
0 10 20 30 40 50 60 70
time (min)
20 °C
37 °C
50 °C
60 °C
70 °C
Fig. 1. L-asparaginase efficiency to acrylamide mitigation in
dependence on the incubation temperature (20, 37, 50, 60 and
70 °C) in a model system
amino acids (ppb)
5,0
4,5
4,0
3,5
3,0
2,5
2,0
1,5
1,0
0,5
0,0
0 20 40 60 80 100 120 140
time of incubation (min)
Asn Bellarosa 2 U/g Asn Marabel 2 U/g
Asn Bellarosa 10 U/g Asn Marabel 10 U/g
Asp Bellarosa 2 U/g Asp Marabel 2 U/g
Asp Bellarosa 10 U/g Asp Marabel 10 U/g
Fig. 2. Conversion of asparagine to aspartic acid by L-asparaginase
application (2 and 10 u g –1 , 37 °C) in 2 varieties of potatoes
(Marabel, bellarosa)
C e r e a l P r o d u c t s P r e p a r a t i o n
Typical Spanish cereal products rosquillas were preapared
from dough according to three different and simplified
recipes consisted of flour, sugar or equimolar mixture of glucose
and fructose, in water (flour : sugar : water was in 4 : 1 : 2
ratio). In one recipe also sodium bicarbonate was added.
From the dough samples of 10.0 ± 0.5 g weight and stick
shape were formed and fried in sunflower oil in a fryer (Taurus,
Spain). 4 samples in one run and also in duplicate were
prepared for each temperature (180 and 200 °C), time (4, 6,
8 min) for each recipe (control and two levels of L-asparaginase:
100 and U kg –1 of flour). The dough with enzyme was
incubated at 37 °C for 15 min in thermostat (Memmert, Germany).
s611
Results
The content of asparagine in potato varies in the range
from 2.3 to 39.4 mg g –1 of dry weight 7 that was comprised
in a simulated potato matrix construction. Using different
concentration of enzyme (2, 10 and 20 U g –1 ), time and temperature
of enzyme incubation (at 20, 37, 50, 60 and 70 °C
for 5–60 min) the efficiency of L-asparaginase activity was
compared. It was found out that temperature of 37 °C was
the most suitable for sufficient acrylamide content elimination
(Fig. 1.). In the case of potato matrix the time of enzyme
incubation was reckoned as a limiting factor. After 30 min at
37 °C acrylamide reduction in final heated samples in levels
of 8, 25 and 46 % was achieved and 91 % using 60 min of
enzyme incubation.
The content of asparagine in the used potato samples
was determined on 4.42 mg g –1 of fresh weight for variety
Marabel and 3.52 mg g –1 of fresh weight for variety Bellarosa.
Two levels of L-asparaginase (2 and 10 U g –1 ) were
applied and incubated at 37 °C. In potatoes the conversion
of asparagine to aspartic acid was observed to be very fast
(Fig. 2.) resulting in a sufficient acrylamide elimination
(98–99 % in Marabel and 84–86 % in Bellarosa) after 10 min
of enzyme incubation.
The content of asparagine in potato pancakes was
2.2 mg g –1 of powder. Using 1 U g –1 of L-asparaginase and
15 min of enzyme incubation at 37 °C, the 86% reduction of
acrylamide content in a final product was achieved. no differences
in sensory properties caused by enzyme were observed
in the appearance (colour, texture) as well as in the taste
and the aroma.
The asparaginase application in the simulated cereal matrix
resulted in 18, 90 and 96% reduction of acrylamide using
enzyme concentration of 0.1, 0.5 and 1.0 U g –1 , respectively,
which was followed by enzyme treatment of cereal products.
This time the determination of final acrylamide reduction in
these products is in progress.
Conclusions
L-asparaginase application is proved to be an effective
way of acrylamide reduction in potato and cereal products. In
the presented study the 80–98 % of acrylamide elimination
was achieved in dependence on matrix composition. Unambiguously,
the distinctive advantage of L-asparaginase application
is the avoiding undesirable changes in organoleptic
properties of final products.
This work was supported by the Slovak Research and
Development Agency under the contract No. COST-0015-06.
REFEREnCES
1. Stadler R. H. et al.: J. Agric. Food Chem. 52, 5550
(2004).
2. Mestdagh F. et al.: Food Chem. 106, 914 (2008).
3. Ciesarová Z., Kiss E., Boegl P.: J. Food nutr. Res. 45,
141 (2006).