Modeling growth rate and assessing aflatoxins production by Aspergillus flavus as a function of water activity and temperature on polished and brown rice

he aim of this study was to model the radial growth rate and to assess aflatoxin production by Aspergillus flavus as a function of water activity (aw 0.82 to 0.92) and temperature (12 to 42 °C) on polished and brown rice. The growth of the fungi, expressed as colony diameter (mm) was measured daily,...

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Main Authors: Mousa, Wael, Mohamad Ghazali, Farinazleen, Selamat, Jinap, Mohd Ghazali, Hasanah, Radu, Son
Format: Article
Language:English
Published: Wiley 2013
Online Access:http://psasir.upm.edu.my/id/eprint/30544/1/Modeling%20growth%20rate%20and%20assessing%20aflatoxins%20production%20by%20Aspergillus%20flavus%20as%20a%20function%20of%20water%20activity%20and%20temperature%20on%20polished%20and%20brown%20rice.pdf
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author Mousa, Wael
Mohamad Ghazali, Farinazleen
Selamat, Jinap
Mohd Ghazali, Hasanah
Radu, Son
author_facet Mousa, Wael
Mohamad Ghazali, Farinazleen
Selamat, Jinap
Mohd Ghazali, Hasanah
Radu, Son
author_sort Mousa, Wael
collection UPM
description he aim of this study was to model the radial growth rate and to assess aflatoxin production by Aspergillus flavus as a function of water activity (aw 0.82 to 0.92) and temperature (12 to 42 °C) on polished and brown rice. The growth of the fungi, expressed as colony diameter (mm) was measured daily, and the aflatoxins were analyzed using HPLC with a fluorescence detector. The growth rates were estimated using the primary model of Baranyi, which describes the change in colony radius as a function of time. Total of 2 secondary models were used to describe the combined effects of aw and temperature on the growth rates. The models were validated using independent experimental data. Linear Arrhenius–Davey model proved to be the best predictor of A. flavus growth rates on polished and brown rice followed by polynomial model. The estimated optimal growth temperature was around 30 °C. A. flavus growth and aflatoxins were not detected at 0.82 aw on polished rice while growth and aflatoxins were detected at this aw between 25 and 35 °C on brown rice. The highest amounts of toxins were formed at the highest aw values (0.90 to 0.92) at a temperature of 20 °C after 21 d of incubation on both types of rice. Nevertheless, the consistencies of toxin production within a wider range of aw values occurred between 25 to 30 °C. Brown rice seems to support A. flavus growth and aflatoxin production more than the polished rice.
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spelling upm.eprints-305442015-10-08T04:36:48Z http://psasir.upm.edu.my/id/eprint/30544/ Modeling growth rate and assessing aflatoxins production by Aspergillus flavus as a function of water activity and temperature on polished and brown rice Mousa, Wael Mohamad Ghazali, Farinazleen Selamat, Jinap Mohd Ghazali, Hasanah Radu, Son he aim of this study was to model the radial growth rate and to assess aflatoxin production by Aspergillus flavus as a function of water activity (aw 0.82 to 0.92) and temperature (12 to 42 °C) on polished and brown rice. The growth of the fungi, expressed as colony diameter (mm) was measured daily, and the aflatoxins were analyzed using HPLC with a fluorescence detector. The growth rates were estimated using the primary model of Baranyi, which describes the change in colony radius as a function of time. Total of 2 secondary models were used to describe the combined effects of aw and temperature on the growth rates. The models were validated using independent experimental data. Linear Arrhenius–Davey model proved to be the best predictor of A. flavus growth rates on polished and brown rice followed by polynomial model. The estimated optimal growth temperature was around 30 °C. A. flavus growth and aflatoxins were not detected at 0.82 aw on polished rice while growth and aflatoxins were detected at this aw between 25 and 35 °C on brown rice. The highest amounts of toxins were formed at the highest aw values (0.90 to 0.92) at a temperature of 20 °C after 21 d of incubation on both types of rice. Nevertheless, the consistencies of toxin production within a wider range of aw values occurred between 25 to 30 °C. Brown rice seems to support A. flavus growth and aflatoxin production more than the polished rice. Wiley 2013 Article PeerReviewed application/pdf en http://psasir.upm.edu.my/id/eprint/30544/1/Modeling%20growth%20rate%20and%20assessing%20aflatoxins%20production%20by%20Aspergillus%20flavus%20as%20a%20function%20of%20water%20activity%20and%20temperature%20on%20polished%20and%20brown%20rice.pdf Mousa, Wael and Mohamad Ghazali, Farinazleen and Selamat, Jinap and Mohd Ghazali, Hasanah and Radu, Son (2013) Modeling growth rate and assessing aflatoxins production by Aspergillus flavus as a function of water activity and temperature on polished and brown rice. Journal of Food Science, 78 (1). pp. 56-63. ISSN 0022-1147; ESSN: 1750-3841 10.1111/j.1750-3841.2012.02986.x
spellingShingle Mousa, Wael
Mohamad Ghazali, Farinazleen
Selamat, Jinap
Mohd Ghazali, Hasanah
Radu, Son
Modeling growth rate and assessing aflatoxins production by Aspergillus flavus as a function of water activity and temperature on polished and brown rice
title Modeling growth rate and assessing aflatoxins production by Aspergillus flavus as a function of water activity and temperature on polished and brown rice
title_full Modeling growth rate and assessing aflatoxins production by Aspergillus flavus as a function of water activity and temperature on polished and brown rice
title_fullStr Modeling growth rate and assessing aflatoxins production by Aspergillus flavus as a function of water activity and temperature on polished and brown rice
title_full_unstemmed Modeling growth rate and assessing aflatoxins production by Aspergillus flavus as a function of water activity and temperature on polished and brown rice
title_short Modeling growth rate and assessing aflatoxins production by Aspergillus flavus as a function of water activity and temperature on polished and brown rice
title_sort modeling growth rate and assessing aflatoxins production by aspergillus flavus as a function of water activity and temperature on polished and brown rice
url http://psasir.upm.edu.my/id/eprint/30544/1/Modeling%20growth%20rate%20and%20assessing%20aflatoxins%20production%20by%20Aspergillus%20flavus%20as%20a%20function%20of%20water%20activity%20and%20temperature%20on%20polished%20and%20brown%20rice.pdf
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