Effect of Product Microstructure and Process Parameters on Modified Atmosphere Packaged Bread

The objective of this study was to examine bread microstructure, oxygen diffusion properties, and gas exchange between bread and headspace after packaging in modified atmosphere (MA). Breads were produced at laboratory scale, and industrially produced breads were included as a reference. X-ray microtomography was applied to characterize the microstructure of the bread samples. For each sample type, oxygen diffusivity was calculated based on microstructural parameters. The samples for gas analyses were packaged under MA using vacuum compensation, using two vacuum strengths during the air evacuation step. The total porosity of all laboratory samples was above 75%, except for the side and bottom crusts which had a lower porosity (<70%). The porosities of the crumb and the side crust of the commercial bread were 80 and 76%, respectively. The connectivity density of the crumbs of the laboratory and commercial breads was 8 and 10 mm^?3, respectively. The crust showed a larger resistance to oxygen diffusion than the crumb, but for both bread regions, the diffusivity was maximally ten times smaller than that of oxygen in air. When considering all data obtained from the gas analysis in the headspace immediately after packaging, oxygen levels of 0.1 ± 0.1% for strong vacuum and 3.8 ± 2.9% for weak vacuum were obtained, which differed significantly (p < 0.05). The results of the laboratory samples corresponded well to those of industrially baked breads. It was concluded that vacuum strength during packaging determines gas transport in bread after packaging.     

Dissolved Silicon and Its Origin in Belgian Beers—A Multivariate Analysis

Beer is a quintessential part of Belgian heritage. We performed a detailed analysis of factors controlling Si content in Belgian beers as a case study to coincide with the 2011 IBiS meeting in Antwerp (Belgium). Beer is one of the richest dietary sources of Si. Three decades of research have yielded evidence of a role for Si in human physiology: it plays an essential role in bone mineral density and reduces the biological availability of aluminium. We analysed 119 Belgian beers: highest dissolved Si concentrations were found in high fermentation, traditionally brewed ales. Concentrations ranged between 214 and 2,071 μmol L^???1. This is probably due to the complexity and length of the brewing procedure: longer, more complicated processing and presence of brewing sediment in the bottle allows more Si to dissolve out of the base products like hop, barley or even rice. As a side effect of fermentation, alcohol content was related to Si content.     

Neutralized electrolyzed water efficiently reduces Fusarium spp. in vitro and on wheat kernels but can trigger deoxynivalenol (DON) biosynthesis

Fusarium Head Blight (FHB), caused by a blend of Fusarium species, is a destructive fungal disease of wheat and other small grain cereals. FHB has become an important issue in food and feed industry. Moreover, the majority of FHB pathogens have the ability to synthesize a range of mycotoxins. Although several physical and chemical control measures can be taken to control these fungi in the field, research is needed to provide new techniques for control during storage and transport of cereals. Mounting evidence shows that electrolyzed oxidizing water (EOW) has antimicrobial activity and might be a useful alternative for conventional control measures. The objective of the present work, was to investigate the influence of EOW on outgrowth and germination of Fusarium spp. and deoxynivalenol (DON) production. Both an in vitro and in vivo approach were pursued. In a first approach, a screening of the main FHB causing species was conducted. Secondly, the effect of EOW on Fusarium graminearum and the effect on DON biosynthesis was investigated using a trichothecene knockout mutant. These experiments showed an increase in DON levels upon sub lethal amendments of EOW to F. graminearum spores. In addition, the reactive oxygen species H₂O₂ was shown to govern this induction.Finally, the work was validated on a laboratory scale via an in vivo assay using wheat grains in which the Fusarium outgrowth was measured. The present work demonstrates that EOW has potential to control Fusarium spp. in wheat grains during transport and storage although sub lethal concentrations can result in increased DON biosynthesis.     

Intrinsic microstructural anisotropy in tape cast ceramics by ice templating

Ice templating concepts based on tape cast processing technology are capable of creating continuous columnar-graded pore structures using a wide variety of ceramic oxides with thicknesses from 100 µm up to 1 cm for applications including fuel cells, compositional grading templates, filtration/separation membranes, and catalyst supports. The merging of the tape casting process allows for the preparation of large area flexible green tapes as well as the long-range alignment of the acicular ice crystals transverse to the cross-section, yielding an additional degree of microstructure control beyond traditional freeze cast processing. Moreover, optimization of the freeze tape casting processing parameters has proven effective in tailoring porosity in aqueous cast ceramics. Magnetic resonance microscopy (MRM) combined with scanning electron microscopy (SEM) has revealed inherent microstructural anisotropy in the morphology of pores related to the direction of the cast tape. Due to the ability of MRM to image noninvasively with volume averaging over a range of slice thicknesses, the MRM images provide complementary information to the higher resolution single plane SEM images. Morphological variance as observed at different orientations through the cross-sections of cast yttria stabilized zirconia is reported.     

Electrical and flexural anisotropy in freeze tape cast stainless steel porous substrates

Engineered metal foams have strong potential in applications such as fuel cell electrodes, sensors, variable springs, filtering media, and compositionally graded composite structures. In this study, the variation in mechanical and electrical properties was characterized in engineered porous metal foams with aligned porosity to ascertain the degree of anisotropy that can be induced in these substrates. Porous substrates were prepared by freeze tape casting of powdered ferritic stainless steel. After directional solidification of the slurry, the solvent was sublimed from ~ 1 mm thick tapes, yielding porous green metal compacts which were sintered in a protective atmosphere. The resulting disks exhibit long range ordered acicular pores with substantial anisotropy in the mechanical and electrical properties that is related to the cross sectional pore morphology and connectivity. DC conductivity testing revealed up to 61% variation depending on direction of measurement relative to the alignment of pores. Also, an 89% variation in flexural rigidity in relation to pore orientation was observed in identical disks.     

The flavonoid tangeretin activates the unfolded protein response and synergizes with imatinib in the erythroleukemia cell line K562

We explored the mechanism of cell death of the polymethoxyflavone tangeretin (TAN) in K562 breakpoint cluster region‐abelson murine leukemia (Bcr‐Abl+) cells. Flow cytometric analysis showed that TAN arrested the cells in the G₂/M phase and stimulated an accumulation of the cells in the sub‐G₀ phase. TAN‐induced cell death was evidenced by poly(ADP)‐ribose polymerase cleavage, DNA laddering fragmentation, activation of the caspase cascade and downregulation of the antiapoptotic proteins Mcl‐1 and Bcl‐x_L. Pretreatment with the pancaspase inhibitor Z‐VAD‐FMK_blocked caspase activation and cell cycle arrest but did not inhibit apoptosis which suggest that other cell killing mechanisms like endoplasmic reticulum (ER)‐associated cell death pathways could be involved. We demonstrated that TAN‐induced apoptosis was preceded by a rapid activation of the proapoptotic arm of the unfolded protein response, namely PKR‐like ER kinase. This was accompanied by enhanced levels of glucose‐regulated protein of 78 kDa and of spliced X‐box binding protein 1. Furthermore, TAN sensitized K562 cells to the cell killing effects of imatinib via an apoptotic mechanism. In conclusion, our results suggest that TAN is able to induce apoptosis in Bcr‐Abl+ cells via cell cycle arrest and the induction of the unfolded protein response, and has synergistic cytotoxicity with imatinib.     

Mechanism for SOFC anode degradation from hydrogen sulfide exposure

Recent results on solid oxide fuel cells with Ni/YSZ and Ni/GDC anodes reveal a mechanism for permanent performance degradation due to hydrogen sulfide exposure. Our results confirm the temporary performance decline observed by others but also reveal a mechanism for the long term permanent degradation. We find that hydrogen sulfide leads to nickel migration and depletion in the anode, thereby compromising electrical conductivity and cell performance.