3. FOOD ChEMISTRy & bIOTEChNOLOGy 3.1. Lectures
3. FOOD ChEMISTRy & bIOTEChNOLOGy 3.1. Lectures
3. FOOD ChEMISTRy & bIOTEChNOLOGy 3.1. Lectures
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Chem. Listy, 102, s265–s1311 (2008) Food Chemistry & Biotechnology<br />
Q u a n t i f i c a t i o n a n d Q u a l i t y<br />
A s s u a r a n c e<br />
The sample analysis was carried out in three repetitive.<br />
Matrix-matched standards of samples were prepared as<br />
described above with the only one difference, residue after<br />
crude extract evaporation was dissolved in toxins standard<br />
solution (methanol: water, 1 : 1, v/v). By means of described<br />
analytical method the limits of detection were achieved<br />
in range 0.5–5 ng ml –1 for measured mycotoxins.<br />
Results<br />
The levels of Fusarium toxins found in wheat grains,<br />
whole-wheat flour and breads prepared by three alternative<br />
procedures are summarized in Table I. Out of 8 monitored<br />
target mycotoxins only nIV, DOn and its conjugates ADOns<br />
and DOn-3-Glc were present at levels exceeded method detection<br />
limits. no Fus-X, HT-2, T-2 and ZOn were found in<br />
examined samples. It should be noted, that conjugated DOn<br />
was contained in experimental wheat at relatively high level,<br />
in this particular case the DOn-3-Glc: DOn ratio value was<br />
approximately 3 : 10, while in previous studies the ratio was<br />
reported to be 1 : 10 ref. 2 .<br />
Within the baking experiments decrease of both DOn<br />
and DOn-3-Glc occurred (up to 33 % and 49 %, respectively),<br />
ADOns and nIV decreased below the limits of detection.<br />
Although no significant differences in mycotoxins<br />
levels were obtained in bread loaves prepared under various<br />
experimental conditions, some indirect correlation between<br />
DOn and DOn-3-Glc concentrations could be seen. The<br />
longer was fermentation and proofing phase the lower was<br />
DOn decrease, while decline DOn-3-Glc was higher. These<br />
results indicate a potential breakdown of DOn-3-Glc during<br />
bread-making yielding in free DOn. At the same time other<br />
unknown transformations of these mycotoxins take place<br />
resulting in overall lower trichothecenes levels in bread in<br />
comparison with wheat taken into the process.<br />
Table I<br />
Levels of mycotoxins in wheat, flour and bread variations<br />
Sample<br />
Mycotoxins [μg kg–1 ]<br />
DOn DOn-3-Glc ADOns nIV<br />
Wheat 469 162 73 47<br />
Flour 337 102 23 15<br />
Bread-var.1 263 29 < 5 < 5<br />
Bread-var.2 278 25 < 5 < 5<br />
Bread-var.3 292 22 < 5 < 5<br />
The data obtained in the second part of experiments concerned<br />
with beers are presented in Table II. The majority of<br />
beers contained detectable levels of DOn, ADOns and DOn-<br />
3-Glc. Occurrence of DOn-3-Glc was shown in all of light<br />
s695<br />
Table II<br />
Levels of mycotoxins in beers<br />
Beer Mycotoxin Incidence Mean Range<br />
[μg dm –3 ] [%] [μg dm –3 ] [μg dm –3 ]<br />
DOn 82 12.9 1.5–3<strong>3.</strong>7<br />
Light DOn–3–Glc 100 16.3 <strong>3.</strong>2–38.0<br />
ADOns 69 8.1 <strong>3.</strong>9–27.8<br />
DOn 84 9.3 1.0–29.5<br />
Dark DOn–3–Glc 92 11.0 2.5–40.2<br />
ADOns 71 8.8 5.1–19.8<br />
beer samples. Interestingly, its mean levels exceeded DOn<br />
levels in light as well as dark beers. Although bioavailability<br />
of DOn-3-Glc has not been documented until now, guestion<br />
arises whether this “masked” DOn does not increase the<br />
healt risk associated with trichothecenes dietary intake. The<br />
relative ratio of DOn-3-Glc and DOn in beers ranged from<br />
0.8 to 1.<strong>3.</strong><br />
Conclusions<br />
The results obtained in this study can be summarized as<br />
follows:<br />
(i) Some decrease of Fusarium mycotoxins including<br />
DOn and its major conjugates ADOns and DOn-3-Glc occurred<br />
during baking.<br />
(ii) no significant impact of the tested technological<br />
times (proofing and fermentation) was observed.<br />
(iii) Extensive contamination of beers obtained at Czech<br />
market demonstrated. The levels of DOn, ADOns and DOn-<br />
3-Glc in light and dark beers were comparable, the later compound<br />
was dominating.<br />
This study was carried out within the scope of research<br />
projects NPV II, 2B08049 supported by the ministry of Education,<br />
Youth and Sports of the Czech Republic.<br />
REFEREnCES<br />
1. Berthiller F, Dall’Asta Ch, Schuhmacher R, Lemmens<br />
M, Adam G, Krska R.: J. Agric. Food Chem. 53, 3421<br />
(2005).<br />
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