A new physical and biological strategy to reduce the content of zearalenone in infected wheat kernels: the effect of cold needle perforation, microorganisms, and purified enzyme.

With the aim of reintroducing wheat grains naturally contaminated with mycotoxins into the food value chain, a decontamination strategy was developed in this study. For this purpose, in a first step, the whole wheat kernels were pre-treated using cold needle perforation. The pore size was evaluated by scanning electron microscopy and the accessibility of enzymes and microorganisms determined using fluorescent markers in the size range of enzymes (5 nm) and microorganisms (10 µm), and fluorescent microscopy. The perforated wheat grains, as well as non-perforated grains as controls, were then incubated with selected microorganisms (Bacillus megaterium Myk145 and B. licheniformis MA572) or with the enzyme ZHD518. The two bacilli strains were not able to significantly reduce the amount of zearalenone (ZEA), neither in the perforated nor in the non-perforated wheat kernels in comparison with the controls. In contrast, the enzyme ZHD518 significantly reduced the initial concentration of ZEA in the perforated and non-perforated wheat kernels in comparison with controls. Moreover, in vitro incubation of ZHD518 with ZEA showed the presence of two non-estrogenic degradation products of ZEA: hydrolysed zearalenone (HZEA) and decarboxylated hydrolysed ZEA (DHZEA). In addition, the physical pre-treatment led to a reduction in detectable mycotoxin contents in a subset of samples. Overall, this study emphasizes the promising potential of combining physical pre-treatment approaches with biological decontamination solutions in order to address the associated problem of mycotoxin contamination and food waste reduction.

Impact of selected baking and vacuum cooling parameters on the quality of toast bread.

Vacuum cooling of baked goods can deliver many advantages in terms of product quality and productivity, such as higher volumes and shorter cooling times. However, the associated high costs and the need to adjust baking protocols are of relevance and more information is needed. This paper examines the influence of two main baking protocol parameters on the quality of toast bread, i.e. oven temperature and baking time reduction. Resulting toast bread characteristics including specific bread volume, concavity, browning index, crust and crumb hardness and aw-value were analysed as well as process-dependent core temperature and water loss. In order to compensate for water loss during vacuum cooling and still achieve optimal toast bread quality, a final bread core temperature of 98 °C at the end of baking gave best results, regardless of oven temperature. It was further shown that cooling time can be reduced by a factor of 10 if the baking protocol is optimally adjusted, hinting at a huge potential to increase productivity for industrial applications. In summary, it can be stated that vacuum cooling requires a tailored reduction in baking time in order to compensate for water loss from vacuum cooling while retaining sufficient structural cohesion to resist deformation of the bread.