Storage of dough at low temperatures (‐20°C) has a considerable effect on the final quality of baked bread; this is most obviously reflected in lowered specific volumes. In this study, a suite of structural characterization techniques is applied to examine the underlying mechanism of storage damage at the molecular, microstructural, and macroscopic level. By using infrared spectroscopy, the dehydration of the gluten component could be established at the molecular level, and its kinetics could be monitored in time. Time‐domain nuclear magnetic resonance (NMR) showed increased water mobility, which could be attributed to a release of water from the gluten matrix. At the microstructural level, the growth of ice crystals could be monitored by means of cryogenic scanning electron microscopy (cryo‐SEM). These ice crystals are preferably formed in gas cells with kinetics that are slower than those during infrared spectroscopy but similar to those in time‐domain NMR. At the macroscopic level, ice crystals are not evenly distributed over the molded dough, nor are the gas cells homogeneously distributed over the dough. This has implications for the macroscopic water distribution during frozen storage, which could be substantiated by magnetic resonance imaging (MRI) measurements.

Communications induce nucleation of the (001) (ab) face of aragonite,[71 possibly by correspondence between the tridentate headgroup and planar carbonates of this face.Finally, we note that the CI6ISA monolayer functions in an analogous manner to the P-pleated sheet matrix of nacre biomineralization. In both cases, the supramolecular organization is produced by hydrogen bonding and the surface periodicities are commensurate with Ca-Ca distances in the specific crystal faces of aragonite. A laboratory analogue based on biomimetic principles provides an opportunity to improve our understanding of alternative synthetic pathways to the controlled formation of inorganic materials with selected polymorph structures.In summary, it has been demonstrated that aragonite can be selectively nucleated without the use of additives. This result strongly supports the concept that functionalization and supramolecular organization play a key synergistic role in controlled crystallization in biological and synthetic systems. ExperimentalOriented nucleation of aragonite was achieved by spreading and compressing a Langmuir monolayer of CI61SA on the surface of a supersaturated calcium bicarbonate solution (pH-5.84.0, T = 21 "C, [CaZQ] = 9-9.5 mM). The latter was prepared by purging C 0 2 gas for 1 h through a suspension of calcium carbonate in water, followed by filtering and purging again for 0.5 h. We chose C161SA as the organic template because it was a likely candidate for a hydrogen-bonding network as observed from crystallographic data of CIZISA . EtOH [21]. This network forms due to the presence of the meta-disposed carboxyl groups of the Cl,jISA benzene rings, and was expected therefore to provide a preorganized supramolecular motif significantly different from the pseudo-hexagonal lattices of conventional surfactants used previously to induce nucleation of inorganic crystals at the monolay erisolution interfaces.After 12 h, a white sheet of CaC03 crystals was visible under the C&A monolayer. X-ray diffraction of samples collected from the surface showed that 75-95 % of the crystals were aragonite (observed d-spacings in A: 3.40 grown in the absence of the monolayer were predominantly calcite. The specificity for aragonite nucleation was highly sensitive to the structural nature of the monolayers. For example, the highest nucleation density of aragonite (12 * 3 imm') was observed under monolayers compressed within the pressure range 1C-15 mNim. This was consistent with AFM studies, which showed a well-defined uniform C161SA monolayer deposited on a hydrophilic silicon substrate at this surface pressure. In contrast, broken ClhISA monolayers were deposited at 20 mNim, although this pressure is well below the collapse point.Color tunability towards the blue part of the visible spectrum has proven to be one of the hardest goals to achieve for both organic and inorganic emitters. Although easy tunability in the blue is not a specific peculiarity of organics, cost criteria and the drive to scale-up dimensions of possible applicati...

tween the aligned MoO 6 octahedra, forming a sinusoidal pattern in a plane perpendicular to the oxide sheets; the phenyl rings, however, are tipped away from this plane about a dihedral angle of about ±13. This model was used in fitting the 1D data shown in Figure 2, and will also be used in our further studies to simulate the 2D Sync MAS data. Significantly, the polymer structure within the layers is similar to that of the oligoaniline ªpentamerº (five phenyl-ring molecule) determined by crystallographic studies. [14] The structure of PANI itself is not known, owing to its insolubility and lack of crystallinity.The 2 H NMR results provide substantial detail concerning the polymer in (PANI) 0.24 MoO 3 , as these show that order is not determined solely by the oxide layers, but is manifested by the polymer between the layers as well. The oxide host acts as a highly anisotropic 2D ªcageº that can be readily aligned on glass slides, which in turn can be oriented in the magnetic field. This allows the structure of the PANI chains to be probed as a function of orientation of the oxide host. Such a study is only possible in the nanocomposite, as bulk PANI cannot be oriented in a similar fashion. The combination of 1D and 2D Sync MAS 2 H NMR provides unique and irrefutable evidence as to the preferential orientation of polyaniline within the molybdenum trioxide host lattice. We add that the heterogeneity of the local carbon site environments along the polymer chain made characterization of order using high-resolution 13 C cross polarization (CP) MAS NMR fruitless. In contrast, solid-state 2 H NMR is uniquely suited to providing this information, by virtue of the large quadrupolar local field that dominates the spectra. Thus, 2 H NMR studies of polymers intercalated within transition metal oxide hosts can provide important and unique information about the structure of the polymer that cannot be obtained by other methods. Further investigations of these materials, including two-dimensional NMR experiments to better characterize the distribution [15] and electrochemical and NMR studies of lithium insertion in these materials, are ongoing. [5] Solid-state NMR spectra of perdeuterated polyaniline nanocomposites were performed at 11.7 T, for which the 2 H Larmor frequency was 76.77 MHz. The quadrupole echo pulse sequence was used, with 90 pulse widths of 2.0±2.2 ms when radio-frequency pulses of approximately 450 W were applied. As well, a much shorter pulse (0.5± 1.0 ms) was used for the initial excitation of the spins, with no difference due to finite pulse width effects evident in the spectra when compared to those obtained with the traditional 90±90 sequence. Acquisition was initiated before the peak of the quadrupole echo with subsequent left-shifting of the free-induction decay to ensure the peak of the echo was correctly obtained. Spectral widths of 1 MHz were used, corresponding to dwell times of 1 ms between each of the 8192 complex time-domain points collected.

Dough processing is an important factor determining the quality of bread. The most important mechanical steps in industrial dough processing are kneading, extrusion, and molding. In all of these processing steps, considerable changes in the structure and properties of the dough can occur. On a laboratory‐scale level, these (structural) effects are well characterized but, so far, no systematic study has been performed at the level of a large‐scale industrial dough processing line. The molecular and microstructural changes that can take place during industrial dough processing were studied with the help of nuclear magnetic resonance (NMR), fundamental rheology, and scanning electron microscopy (SEM). After the kneading step, the dough shows a well‐developed gluten network with a homogeneous dispersion of starch particles (at optimum kneading time). After the extrusion step (a sheeting procedure), the structure of the dough becomes coarser and the dough gluten network is oriented and partially disrupted. This is accompanied with an increase in both rheological stress and water mobility. After molding, the network structure is restored and both the rheological stress and the mobility of water decrease. These findings provide a novel microstructurally‐lead approach to make recommendations for optimization of industrial dough processing lines.

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