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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Cereal Crops Research » Research » Publications at this Location » Publication #329570
Research Project: Enhancement of Hard Spring Wheat, Durum, and Oat Quality

Location: Cereal Crops Research

Title: Transformation of adsorbed aflatoxin B1 on smectite at elevated temperatures

Author
item SADIA, ASMA - University Of Veterinary And Animal Sciences
item Dykes, Linda
item DENG, YOUJUN - Texas A&M University

Submitted to: Clays and Clay Minerals
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/23/2016
Publication Date: 9/2/2016
Publication URL: http://handle.nal.usda.gov/10113/5700707
Citation: Sadia, A., Dykes, L., Deng, Y. 2016. Transformation of adsorbed aflatoxin B1 on smectite at elevated temperatures. Clays and Clay Minerals. 64(3):220-229. doi:10.1346/CCMN.2016.0640306.

Interpretive Summary: Aflatoxins cause liver damage and suppress immunity. Smectites can be used to reduce the bioavailability of aflatoxins through adsorption. To further reduce the toxicity of aflatoxins and to eliminate the treatments of aflatoxin-loaded smectites, degrading the adsorbed aflatoxin to nontoxic or less toxic compounds would be desirable. The objective of this study was to investigate the effects of temperature and exchange cation on the transformation of adsorbed aflatoxin B1 on smectite. An AfB1-Ca-smectite (sm) complex was synthesized and the exchange calcium in the complex was replaced with either manganese or copper to enhance the Lewis acidity of the complexes. The aflatoxin complexes and pure aflatoxin B2 were dried and then heated from 100 to 200 C at 25 C increments. The samples were then extracted with methanol prior to UV spectroscopy, HPLC-Fluorescence-UV, and UPLC-PDA-MS-TQD. The solid residues were analyzed by FT-IR. The extracts showed a gradual decrease in aflatoxin B1 with increased heating temperature and the formation of aflatoxin B2, B2a, M1, M2, and other unidentified compounds. These results suggested that smectite can affectively convert aflatoxin to other less toxic forms at elevated temperatures. Smectites saturated with copper or manganese and heat treatment induced more efficient conversion of the adsorbed aflatoxin B1 to other compounds.

Technical Abstract: Aflatoxins cause liver damage and suppress immunity. Smectites can be used to reduce the bioavailability of aflatoxins through adsorption. To further reduce the toxicity of aflatoxins and to eliminate the treatments of aflatoxin-loaded smectites, degrading the adsorbed aflatoxin to nontoxic or less toxic compounds would be desirable. The objective of this study was to investigate the effects of temperature and exchange cation on the transformation of adsorbed aflatoxin B1 on smectite. An AfB1-Casmectite (sm) complex was synthesized. To enhance the Lewis acidity of the complexes, the exchange calcium in the complex was replaced with manganese (Mn) and copper (Cu) to obtain AfB1-Mn-sm and AfB1-Cu-sm complexes, respectively. The aflatoxin-sm complexes and pure aflatoxin B1 were dried at 60 oC in aluminum cups, and heated from 100 to 200 C using 25 C steps. Aflatoxin B1 and its transformation products were extracted with methanol after the heating treatment. The extracts were analyzed with UV spectroscopy, high performance liquid chromatography (HPLC)-fluorescence/UV, ultra performance liquid chromatography (UPLC)-photodiode array (PDA) and electrospray ionization-tandem quadrupole-mass spectrometry (ESI-TQDMS). The solid residues were analyzed with Fourier transform infrared spectroscopy (FTIR). The UV and FTIR spectra of the AfB1-sm clay residue extracts obtained after heating had decreased AfB1 peak intensities and shifted peak positions with increased heating temperature. Prominent shifts in band positions and shape of the UV spectra were observed in the extracts from 175 C heated AfB1-Ca-sm complex, 150 C heated AfB1-Cu-sm complex, and 125 C heated AfB1-Mn-sm complex. The HPLC and UPLCMS analyses of AfB1-sm complex extracts indicated a gradual fB1 concentration decrease with increased heating temperature and the formation of aflatoxins B2, B2a, M1, M2, and other unidentified compounds. No new compound was observed in the extracts of pure aflatoxin B1 after a comparable heating experiment. These results suggest that smectite can effectively convert aflatoxin to other less toxic forms at elevated temperatures. Smectite ion exchange with Cu or Mn Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation transition metals cations and heat treatment induced more efficient conversion of the adsorbed aflatoxin B1 molecules to other compounds.