Hidden Fumonisins: Simple and Innovative Extractions for Their Determination in Maize and Derived Products

Fumonisins B (FBs) can occur in maize as free\r\nforms and as hidden FBs (interaction between FBs and matrix\r\nmacro-constituents). The analytical methods to detect free\r\nFBs in maize and derived products usually involve extraction\r\nwith aqueous methanol and/or acetonitrile; for hidden FBs,\r\nalkaline hydrolysis (2MKOH) and following CH3CN extraction\r\nis used. Recently, we proposed a simple phosphate buffer\r\n(PB) extraction to detect free FBs in masa and maize samples.\r\nThis study aimed at evaluating if this method is suitable to\r\ndetect also hidden FBs; then, a comparison between the most\r\ncommon solvents, PB, and alkaline hydrolysis was carried\r\nout. For maize samples, the results showed that 0.4 M PB\r\ncan extract both free and most hidden FBs; however, this\r\nmethod was not suitable for some categories of maize-based\r\nprocessed food products, in particular cornflakes, chips, and\r\ncrispbreads. To solve this drawback, a modified PB extraction,\r\nwhich entails the addition of Carrez solutions in order to precipitate\r\nproteins, was tested and satisfactory results were obtained.\r\nFinally, the alkaline hydrolysis of maize-based food\r\nextracts showed that bound FBs can be co-extracted\r\ntogether with free forms by 0.4 M PB and quantified\r\nas hydrolyzed FBs.