Texture and breakdown in the mouth: An industrial research approach.

Unlabelled: Texture is one of foods' most important qualities, but is a sensory perception by consumers. To understand, predict and design for sensory appeal, we must codify the sensory response and diagnose the physical stimuli in the mouth which give rise to perception. This brief review examines the leading contributions from Szczesniak and Bourne and shows the developments in the field, built on their earlier contributions.

Designing food structures for nutrition and health benefits.

In addition to providing specific sensory properties (e.g., flavor or textures), there is a need to produce foods that also provide functionality within the gastrointestinal (GI) tract, over and above simple nutrition.

Effect of solutes and matrix structure on water mobility in glycerol-agar-water gel systems: a nuclear magnetic resonance approach.

Nuclear magnetic resonance spectroscopy (NMR) has been widely used to determine water molecular mobility in food systems. This study aimed to examine the effects of matrix structure and solutes on the dynamics of water molecules in model mixed systems, glycerol-agar-water gels, using low- and high-resolution NMR. Simple models to explain water relaxation rates and self-diffusion coefficients in mixed systems were developed using the experimental values obtained for the individual binary systems (glycerol-water solutions and agar-water gels).

Chemical modification of gelatin by a natural phenolic cross-linker, tannic acid.

Chemical modification of gelatin by a natural phenolic compound tannic acid (TA) at pH 8 was studied, and the properties of the modified gelatin materials were examined. The cross-linking effect was predominant when the TA content was lower, resulting in the formation of a partially insoluble cross-link network. The cross-linking structure was stable even under boiling, and the protein matrix became rigid, whereas the mechanical properties were enhanced.

Chemical cross-linking gelatin with natural phenolic compounds as studied by high-resolution NMR spectroscopy.

Cross-linking gelatin with natural phenolic compound caffeic acid (CA) or tannic acid (TA) above pH 9 resulted in formation of insoluble hydrogels. The cross-linking reactivity was controlled by variation of pH, the concentration of the gelatin solution, or the amount of CA or TA used in the reaction. The cross-linking chemistry was studied by high-resolution NMR technique in both solution and solid state via investigation on small molecular model systems or using (13)C enriched caffeic acid (LCA) in the reaction with gelatin.

Structure and molecular mobility of soy glycinin in the solid state.

We report a multitechnique study of structural organization and molecular mobility for soy glycinin at a low moisture content (<30% w/w) and relate these to its glass-to-rubber transition. Small-angle X-ray scattering (SAXS), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy are used to probe structure and mobility on different length and time scales. NMR (approximately 10(-6) to 10(-3) s) reveals transitions at a higher moisture content (>17%) than DSC or SAXS, which sample for much longer times (approximately 10 to 10(3) s) and where changes are detected at >13% water content at 20 degrees C.

Processing of novel elevated amylose wheats: functional properties and starch digestibility of extruded products.

Different types of novel wheat lines with different starch contents and amylose/amylopectin ratios, relating to defined alterations in the number and activity of starch synthase IIa genes, were processed by pilot-plant extrusion. Two types of products were produced: pure wholemeal products and breakfast cereals made from wholemeal/maize blends. Lower apparent shear viscosity was obtained in the extruder with lower starch content and higher amylose/amylopectin ratio flours (SSIIa-deficient line).

Thermal properties of bacterial spores and biopolymers.

Differential scanning calorimetry (DSC) measurements of dormant bacterial spores is traditionally associated with an endothermic transition at around 50 degrees C. This endothermic transition was described as an indicator for two main physico-chemical states in spores. These were a glassy state in the dormant spore core as a model for spore dormancy and a heat-activated state that generally facilitates spore resuscitation.

In vitro uses of biological cryoprotectants.

Ice can be anything from a highly destructive agent in agriculture to a useful building material. Established industries are based on the known rules of physics and chemistry which allow some control of amounts of ice or ice crystal geometry. However, organisms have much more subtle requirements to maintain their delicate internal structure if they are to survive freezing.

Effects of hydration on molecular mobility in phase-bright Bacillus subtilis spores.

The molecular mobility of 31P and 13C in dormant Bacillus subtilis spore samples with different water concentrations was investigated by high-resolution solid-state NMR. Lowest molecular mobility was observed in freeze-dried preparations. Rehydration to a 10% weight increase resulted in increases in molecular motions and addition of excess water furthered this effect.