Preparation of strontium-based fibers via electrospinning technique

The Sr-based fiber was prepared by electrospinning process. The effect of electric field, precursor viscosity, and calcination temperature (T_cal) was investigated at required conditions. Then the Sr-based fiber was characterized by TGA, nitrogen adsorption, SEM, TEM, and XRD to elucidate thermal transition, specific surface area, morphology, crystal structure, and crystalline phase of the samples, respectively. The result showed that the smooth fiber sample could be spun at electric field of 1.5 kV cm^?1 with the suitable viscosity of ca. 5 Pa s. Finally the crystalline phase could be controlled by properly adjusting T_cal, i.e. when the T_cal was risen from 400 to 1000 °C, the crystalline phase was transformed from SrCO₃ to Sr(OH)₂H₂O, and eventually to SrO.     

Novel peptides from dried squid head by-products obtained from snack process

The novel peptides were successfully produced with commercial protease hydrolysis (Alcalase® and Flavourzyme®) at the fixed concentration of 3%by weight of protein in substrate. The hydrolysis was performed at various hydrolysis times (0, 300, 450, 600 and 750 min) at the optimal pH and temperature. When the hydrolysis was performed until 750 min, the peptide solutions with high soluble protein content were resulted (47.58 and 42.53 mg protein per mL for Alcalase® and Flavourzyme® hydrolysis, respectively). After freeze drying, the peptide powder from Alcalase® and Flavourzyme® hydrolysis had degree of hydrolysis at 71.87% and 66.39%, respectively. Alcalase® hydrolysis provided the novel peptide fraction with DPPH scavenging, ABTS activity and ACE-inhibitory activity at 64.20%, 102.50 µg mL⁻¹ and 56.98%, respectively. This peptide fraction possessed the lowest molecular weight (m/z 807.418) as detected by MALDI-TOF/MS, and the most potent peptide sequence was Arg-Glu-Gly-Tyr-Phe-Lys which has the potential as functional ingredient in novel food, snacks and beverages.     

Effect of Calcination Conditions and Excess Alkali Carbonate on the Phase Formation and Particle Morphology of Na0.5K0.5NbO3 Powders

Sodium-potassium niobate [Na_0.5K_0.5NbO₃] powders were prepared following the conventional mixed oxide method. An orthorhombic XRD pattern, consistent with single-phase Na_0.5K_0.5NbO₃, was obtained after calcination at 900°C for 6 h. Introducing 5 mol% excess Na₂CO₃ and K₂CO₃ into the starting mixture allowed milder calcination conditions to be used, for example 800°C for 2 h. Primary particles in 5 mol% excess samples were cuboid, with maximum sizes of ∼2.5 μm. Equiaxed 0.3–0.4-μm particles were formed for non-excess powders, and also for powders prepared with 1 and 3 mol% excess alkali carbonates. The results suggest liquid formation during calcination of the excess 5-mol% starting powders.