Effects of extrusion conditions on secondary extrusion variables and physical properties of fish, rice-based snacks

A formulation containing rice flour, fish powder, menhaden oil and vitamin E was extruded at a feed rate of 10 kg/h using a co-rotating twin-screw extruder. Primary extrusion (independent) variables were temperature (125-145 °C), screw speed (150-300 rpm) and feed moisture (19-23 g/100 g db). Response surface methodology (RSM) was used to study the effects of extrusion conditions on secondary extrusion variables (product temperature, pressure at the die, motor torque, specific mechanical energy input and mean residence time) and physical properties of the extrudates. Second-order polynomial models were computed and used to generate contour plots. Increasing feed moisture and screw speed decreased pressure at the die. Increased screw speed increased product temperature at the die but increased feed moisture lowered it. Increased barrel temperature, feed moisture and screw speed decreased motor torque. Increased screw speed increased specific mechanical energy, while increased feed moisture reduced it. Longer mean residence times were observed at lower screw speeds. Product density increased as feed moisture increased, but decreased with screw speed. Increased feed moisture decreased radial expansion.     

Electroactive polymer actuator from highly doped permethylpolyazine dispersed in ethylene propylene diene elastomer

Structural, electronic, and optical properties of a series of ??-conjugated thiophene oligomers P1-P3 and CF ₃ P1-CF ₃ P3 have been theoretically investigated. P1-P3 contain the 2- (trifluoromethyl) thieno [3, 4-b] thiophene moiety as the centre and 1?C3 repeating thiophene units adjacent to its two sides respectively, while their corresponding derivatives CF ₃ P1-CF ₃ P3 with the CF₃ as end-caps. The geometric structures of the oligomers in the ground and excited state were optimized by PBE1PBE and CIS methods with 6?C31G (d) basis sets, respectively. All the oligomers exhibit zigzag arrangements. The absorptions and emissions were calculated by the time-dependent density functional theory method (TD-PBE1PBE). The lowest-lying absorptions of all the oligomers can be characterized as ??-??^* electron transition. For each series of oligomers, there is a progressive lowering in HOMO-LUMO gap with the increase of the repeating unit, being consistent with the red-shifted trend in the lowest-lying absorption and fluorescence from P1 to P3 and CF ₃ P1 to CF ₃ P3. To compare the P- and corresponding CF ₃ P-oligomers, the end-cap CF₃ group causes the slight blue shifts in absorption and emission spectra. The ionization potentials (IP_S), electron affinities (EAs), and reorganization energies (??) as well as the hole/electron extraction energies (HEP/EEP) of the oligomers were explored and those of the corresponding polymer were obtained by extrapolation method. The IP and HEP of P-polymer are lower than those of CF ₃ P-polymer, indicating that the P-polymer is more suitable for hole transport than CF ₃ P-polymer, while the higher EA and EEP for CF ₃ P-polymer suggest the better electron transfer property. For CF₃ end-caps, the CF ₃ P-polymer exhibits the equal reorganization energy between electron and hole, which is a precondition for the charge transfer balance.     

Bio-compatible gelatins (Ala-Gly-Pro-Arg-Gly-Glu-4Hyp-Gly-Pro-) and electromechanical properties: effects of temperature and electric field

Gelatin (Ala-Gly-Pro-Arg-Gly-Glu-4Hyp-Gly-Pro-) is a protein produced by the partial hydrolysis of a collagen extracted from bones, connective tissues, organs, and some intestines of animals. In this work, gelatin films were prepared by the film casting method in an aqueous solvent. The electromechanical properties, thermal properties, and the degree of swelling were investigated as a function of gelatin crosslinking ratio or the gel strength, temperature, frequency, and electric field strength. The high, medium, low, and the 3% crosslinked high-gel-strength gelatin films possess the storage modulus sensitivity values of 2.30, 2.16, 1.26, and 0.49, respectively; these values are much greater than those of other electroactive materials, suggesting the gelatins studied as a potential artificial muscle or actuator.     

Electric field induced stress moduli of polythiophene/polyisoprene suspensions: Effects of particle conductivity and concentration

Electrorheological properties of polythiophene/polyisoprene suspensions were investigated in the oscillatory shear mode under electric field varying from 0 to 2 kV/mm. Poly(3‐thiophene acetic acid) particles were synthesized via an oxidative polymerization and doped with perchloric acid in order to vary electrical conductivity. ER responses can be enhanced with increasing electric field strength, particle electrical conductivity, and particle concentration. The storage modulus (G′) increases dramatically by 3 and 4 orders of magnitude, with the variations of particle conductivity and particle concentration as the electric field strength is increased from 0 to 2 kV/mm The results can be interpreted in terms of the difference in the polarizability between the particles and the matrix, and the particle agglomeration existing at high particle electrical conductivity and high particle concentration. The suspensions exhibit the transitions from the fluid‐like behavior to the solid‐like behavior at the critical electric field strengths. In particular, the sol‐to‐gel transitions occur at lower electrical field strengths with higher particle electrical conductivity and at higher particle concentration.     

Effect of extrusion conditions on physical and chemical properties of high protein glutinous rice-based snack

Two glutinous rice-based snack formulations were designed using a linear-programming model to minimize total cost to meet the FAO/WHO/UNU. (1985). Energy and protein requirements. Report of a joint FAO/WHO/UNU expert consultation. Technical report series 724. Geneva: WHO requirements for lysine and sulphur amino acids. Effects of protein concentration, feed moisture content and barrel temperature on the chemical and physical properties of the extruded product were investigated. Response surfaces for the parameters were generated using a second-degree polynomial. The high protein nutritious snack was obtained using glutinous rice flour, vital wheat gluten and toasted soy grits. A factorial design was employed to investigate the influence of feed protein content (20 and 30 g/100 g wb), feed moisture (20, 25, and 30 g/100 g wb) and barrel temperature (150 and 180 °C) on the physical and chemical properties of extrudates. Results showed that increasing feed moisture and reducing barrel temperature reduced non-protein nitrogen (NPN) and enhanced lysine retention. The protein and moisture content of raw material and barrel temperature had no significant influence on cysteine and methionine content. The conditions providing high expansion, low bulk density, and low shear strength of extruded snack were feed moisture of 20 g/100 g wb and 180 °C.     

Oil Coating Affects Internal Quality and Sensory Acceptance of Selected Attributes of Raw Eggs during Storage

Four (coconut, palm, rice bran, and soybean) edible oils and glycerol were applied on eggshell. All noncoated and coated eggs were stored for 5 wk at 25 ± 2 °C and drawn weekly for quality evaluation. All oil coatings were more effective in preserving internal quality of eggs than was glycerol coating. As storage time increased, the preservative effects of edible oil coating on weight loss, and albumen and yolk quality were significantly noticed. Oil‐coated eggs had significantly lower weight loss (<0.43%) than did noncoated (3.87%) and glycerol‐coated (3.73%) eggs after 5 wk of storage. Based on the Haugh unit, oil‐coated eggs maintained AA grade up to 3 wk. After 5 wk of storage, noncoated, glycerol‐coated, and oil‐coated eggs changed from AA grade to below B, below B and A grade, respectively. The albumen pH of noncoated and glycerol‐coated eggs considerably increased from 8.23 to 9.51 and 9.42, respectively, while those of oil‐coated eggs either maintained or slightly increased to 8.32. The albumen viscosity of all eggs decreased with increased storage time. Consumers (N = 120) could differentiate surface glossiness of oil‐coated eggs from uncoated eggs (R‐index of 81.42% to 86.99%). All oil‐coated eggs were acceptable for surface glossiness (liking scores of 6.22 to 6.77) and surface odor (liking scores of 6.20 to 6.55) with overall liking scores of 6.34 to 7.03. Overall, this study demonstrated that edible oil (coconut, palm, rice bran, and soybean) coating could preserve internal quality of eggs (maintaining grade A) at least 4 wk longer than noncoated eggs. Practical Application: Freshness is a major contribution to the egg quality. The internal quality of eggs begins to deteriorate after they have been laid due to loss of moisture and carbon dioxide via the eggshell pores. Refrigeration is very effective in preserving egg quality. Surface coating is an alternative method to preserve egg quality, although it is much less effective than refrigeration. This study demonstrated that coconut, rice bran, soybean, and palm oils, which are abundant and commonly consumed in many parts of the world, could preserve the internal quality and reduce weight loss of oil‐coated eggs during room temperature storage.