Effectiveness of perforation methods for wheat kernels

Abstract

Wheat is an important staple food worldwide, but often contaminated with moulds, which in specific cas es, form toxic mycotoxins as secondary metabolites. The aim of this study was to investigate different pre processing methods of wheat kernels that allow active agents such as functional microorganisms and en zymes to pass through the water-repellent hyaline layer in order to break down possible mycotoxins into less or non-toxic compounds. To be able to assess the processing efficacy, a qualitative visualisation meth od was developed and implemented. A wide range of processing techniques to perforate the outer layers while maintaining structural integrity of the kernel were tested, including ohmic heating, pulsed electric fields (PEF), ultrasonication, cold needle perforation (CNP), heat stress and steam explosion. It was shown that both the application of PEF as well as CNP are promising paths to perforate the outer wheat layers. The effectiveness of CNP was shown through a combined microscopic approach involving scanning elec tron microscopy and fluorescence microscopy with fluorescing particles in the size range of both enzymes and lactic acid bacteria