Hydration kinetics of direct expanded tef flour breakfast cereals in water and milk
Hydration kinetics of tef flour breakfast cereals extruded at barrel temperatures of 110, 130, and 150°C was investigated by hydrating them in water and whole milk at 25°C (±1°C). The normalized Weibull model described the rehydration characteristics of the extrudates in water and milk adequately (R2 = 0.98–0.99). Water absorption rate was significantly (P < 0.05) influenced by barrel temperature where extrudates processed at 150°C barrel temperature exhibited high water absorption rate followed by those extruded at 130 and 100°C, respectively. Hydration rate and equilibrium moisture content were higher for samples hydrated in water than those in milk. In view of the values of the shape parameter β, the hydration process is predominantly controlled by diffusion (β = 0.40–0.51) for samples extruded at 110°C whereas external resistance to mass transfer dominated (β = 0.60–0.73) those extruded using 150 and 130°C. Extrudates processed at 130 and 150°C exhibited better hydration characteristics. Thus, these temperature ranges could be used to produce extruded products from tef.
Kinetics of bread crumb hydration as related to porous microstructure.
During oral processing and throughout the digestion process, hydration mechanisms have a key influence on the functional properties of food. This is the case with bread, for which hydration may affect the kinetics of starch hydrolysis as well as taste, aroma and texture perceptions. In this context, the aim of the present study is to understand how crumb porous micro-architecture impacts hydration kinetics. Four types of French baguettes were considered, varying in structure and/or compositions. An experimental set-up was developed for the real-time measurement of water uptake in crumb samples. Mathematical models were then fitted to extract quantitative parameters of use for the description and the understanding of experimental observations. Finally, bread crumb samples were analyzed before and after hydration through X-ray micro-computed tomography for the assessment of crumb micro-architectural properties. Distinct hydration behaviors were observed for the four types of bread. Higher hydration rates and capacities were reported for industrial baguettes (highest porosity) compared to denser semi-industrial, whole wheat and traditional baguettes. However, crumb porosity alone is not sufficient to predict hydration behavior. This study made it possible to point out the importance of capillary action in crumb hydration mechanisms, with a strong role of cells with diameters of 2 mm and below. The high density of these small cells generates high interconnection probabilities that may have an impact both on crumb hydration duration and capacity. As a consequence, accounting for microstructural features resulting from bread formulation may provide useful leverages for the control of functional properties.
Effects of Storage Temperature and Duration on Bioactive Concentrations in the Seed and Oil of Brassica napus (Canola)
The effects of storage temperature and duration on phytosterol, tocopherol and carotenoid concentrations are assessed in canola seed, and oil extracted using two different techniques, over a 10 month period. Increases to oxidation indices (K232, K270 and ΔK) are observed in the solvent extracted oils, and in the seed stored at 40 °C, indicating the formation of primary and secondary oxidation products. Only small decreases in the concentrations of γ-tocopherol and β-carotene are observed across the 10 month period. Phytosterol concentration decreases over time, with similar degradation rates observed in both seed and oils. α-tocopherol and lutein are well preserved up to 7 months in all samples, despite oil oxidation, and further research will be needed to identify the cause for retention of bioactives. The results indicate that in order to preserve phytosterols, tocopherols and carotenoids in seed stored in bulk for extended periods, storage temperatures should remain at or below 21 °C. Moreover, oil stored at 4 °C or −18 °C, results in high bioactive concentrations and slows the onset of oil oxidation, compared to oil stored at room temperature. 
 
Practical Applications: Industrial storage conditions have been shown to greatly influence the chemical processes that occur with canola seed and oil. However, the effects of typical storage conditions on phytosterols, tocopherols and carotenoids in canola seed and extracted oil, are not yet known. This study presents the effects of typical seed and oil storage conditions on phytosterol, tocopherol and carotenoid concentrations, whilst monitoring oxidation indices and FFA, and thus provides information to seed handlers and oil processors on storage conditions that may preserve these bioactives. Moreover, the different behaviours of bioactives are examined relative to the oil extraction technique used, and present opportunities to optimise oil extraction techniques. 
 
 
 
Time series plots for α-tocopherol concentrations in canola oil stored at different temperatures over 280 days, illustrating a difference in behaviour between the solvent extracted oil and the hand-press extracted oil.