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conferenceseries
.com
October 27-29, 2016 Rome, Italy
15
th
International Conference on
Food Processing & Technology
Volume 7, Issue 12 (Suppl)
J Food Process Technol 2016
ISSN: 2157-7110 JFPT, an open access journal
Food Technology 2016
October 27-29, 2016
Effects of storage conditions on aflatoxin production and expression levels of some biosynthesis genes of
Aspergillus
flavus
in red pepper
Banu Soylu
1
, Zülal Kesmen
1
, Nurdan Yapar
2
and
Hasan Yetim
1
1
Erciyes University, Turkey
2
Kayseri Food Control Laboratory, Turkey
T
he aim of this study was to determine the relationship between the aflatoxin production of aflatoxigenic
Aspergillus flavus
and
expression levels of aflatoxin biosynthetic metabolic pathway genes (aflR, nor-1 andpksA) in red pepper stored under different
water activities (aw) (0.80, 0.85, 0.90 and 0.95 aw) and temperature conditions (5, 15, 25 and 35
0
C). Cultural mould growth, aflatoxin
analysis, extraction of total RNA were carried out at 0, 1, 2, 3, 4, 5, 7, 10, 15 and 20th days of incubation. Expression levels of the
regulatory gene aflR and two structural genes nor-1 and pksA of the aflatoxin biosynthetic pathway were also assayed by the reverse
transcription real-time polymerase chain reaction (RT-PCR). Also, response surface methodology (RSM) was applied to evaluate
the effects of aw, temperature, time, genes (aflR, nor-1andpksA) expression on aflatoxin B1 (AFB1) production of
A. flavus
and to
predict AFB1 amounts of contaminated red pepper. According to the results, mould counts of samples at 0.80 and 0.85 aw decreased
starting from the third day of storage for all tested temperatures, and the lowest mould counts were obtained at 0.80 aw-25
0
C and 0.80
aw-35
0
C conditions on the 20th day of storage. AFB1contents of the samples increased with the increment of temperature for all aw
levels. The lowest AFB1production was observed under 0.80 aw-5
0
C conditions in the experiment while the highest AFB1amount
(61.56 ppb) was detected at 0.95 aw-35
0
C on 15th day and highest AFB1 amount was observed at 0.95 aw-25
0
C on 15th day (57.21
ppb) of storage. In terms of the model, the effects of aw, temperature and pksA gene expression were very significant (p<0.01), and
the effect of nor-1 gene expression was significant (p<0.05), while the aflR gene expression was insignificant (p>0.05) in explaining of
the AFB1 occurrence in contaminated red pepper stored at 25
0
C. In conclusion, it can be suggested that the growth of aflatoxigenic A.
flavus, amounts of AFB1, gene expression levels of aflR, nor-1andpksA depending on the aw, temperature and time were monitored
in red peppers and AFB1 production was modeled with RSM for the first time in this study. Determination of correlations between
AFB1 production and aw, temperature, time, aflR, nor-1 and pksA expression levels could be helpful to predict potential risk AFB1
accumulation during storage of red peppers.
Biography
Banu Soylu has completed her PhD fromMiddle East Technical University, Ankara, Turkey. She is anAssociate Professor at the Department of Industrial Engineering
in Erciyes University, Kayseri, Turkey. She has been working on the subject of optimization, mathematical modeling and statistical methods of engineering.
bsoylu@erciyes.edu.trBanu Soylu et al., J Food Process Technol 2016, 7:12 (Suppl)
http://dx.doi.org/10.4172/2157-7110.C1.056