Assessment of the arachidonic acid content in foods commonly consumed in the American diet

Arachidonic acid (AA) is an extremely important fatty acid involved in cell regulation. When provided in the diet, it is cogently incorporated in membrane phospholipids and enhances eicosanoid biosynthesis in vivo and in vitro; however, controversy exists as to the levels of AA in food and in the diet. This study determined the amount of AA in cooked and raw portions of beef (rib eye), chicken (breast and thigh), eggs, pork (loin), turkey (breast), and tuna; it compared these results to values published in Agriculture Handbook No. 8 (HB-8). The cooked portions were prepared as described in HB-8. With the exception of chicken thigh and tuna, the levels of AA (w/w) in the selected foods analyzed were significantly higher, in general, than those values published in HB-8. The greatest differences were observed in beef (raw and cooked), turkey breast (raw and cooked), and pork (cooked) where AA levels were twice that of the values in HB-8. In contrast, the AA and n-3 fatty acid contents in tuna were almost half the HB-8 values. The present data indicate that HB-8 tends to underreport the amounts of AA in a number of foods commonly consumed in the American diet, and new initiatives should be considered to validate and update the current database for fatty acid composition of foods.     

Simultaneous liquid–liquid demixing and crystallization and its effect on the spherulite growth in poly(ethylene terephthalate)/poly(ether imide) blends

Poly(ethylene terephthalate) (PET)/poly(ether imide) (PEI) blends were miscible in the melt, but exhibited simultaneous liquid–liquid phase separation and crystallization over a wide range of temperature and composition. The interplay between these two processes is expected to dominate the morphological formation in the blends. In this study, the phase diagram of PET/PEI blend was determined to evaluate the envelop within which liquid–liquid phase separation was operative with crystallization. A UCST phase diagram below 240°C was identified for this system. The effect of liquid–liquid phase separation on the growth of PET spherulites was studied by small-angle light scattering (SALS). Nonlinear spherulite growths were observed for the blends at higher crystallization temperatures of 210°C and 220°C, while the growths were basically linear below 210°C. The nonlinear growth behaviour was discussed based on the competition between spherulite growth and spinodal decomposition.     

Flame Temperature Calculations at High Temperature and Pressure

In the past, real gas effects on the flame temperature were evaluated using the virial equation of state. Usually, the virial expansion was truncated after the third term. In this work the equation of state for dense gases proposed by Haar and Shenker is considered. The implementation developed for H₂O, CO, CO₂, H₂, and N₂ by Powell, Wilmot, Haar and Klein is used. The contribution of all minor species is assumed to be approximated by a Lennard-Jones gas with ϵ/k = 100 K and σ = 3.0 Å. It is found that the more conventional approach is valid up to a loading density of 0.2 g/cm³. As density increases real gas effects cause the calculated flame temperature to decrease and the calculated pressure to increase. A computer program to perform the calculations has been devised for a personal computer.     

Optimization of Incorporated Prebiotics as Coating Materials for Probiotic Microencapsulation

ABSTRACT: The purpose of this research was to improve probiotic microencapsulation using prebiotics and modern optimization techniques to determine optimal processing conditions, performance, and survival rates. Prebiotics (fructooligosaccharides or isomaltooligosaccharides), growth promoter (peptide), and sodium algi-nate were incorporated as coating materials to microencapsulate 4 probiotics ( Lactobacillus acidophilus, Lacto-bacillus casei, Bifidobacterium bifidum , and Bifidobacterium longum ). The proportion of the prebiotics, peptide, and sodium alginate was optimized using response surface methodology (RSM) to 1st construct a surface model, with sequential quadratic programming (SQP) subsequently adopted to optimize the model and evaluate the survival of microencapsulated probiotics under simulated gastric fluid test. Optimization results indicated that 1% sodium alginate mixed with 1% peptide and 3% fructooligosaccharides as coating materials would produce the highest survival in terms of probiotic count. The verification experiment yielded a result close to the predicted values, with no significant difference ( P > 0.05). The storage results also demonstrated that addition of prebiotics in the walls of probiotic microcapsules provided improved protection for the active organisms. These probiotic counts remained at 10⁶ to 10⁷ colony-forming units (CFU)/g for microcapsules stored for 1 mo and then treated in simulated gastric fluid test and bile salt test.     

Phase behavior of poly(3-alkylthiophene)/polystyrene blends

Phase diagrams of blends consisting of poly(3-n-alkylthiopene) having four different n-alkyl side chain lengths (n = 4, 6, 8, 12) and polystyrene (PS) were obtained by turbidity measurement. All of the P3AT/PS blends employed in this study exhibited the upper critical solution temperature (UCST) type phase behavior. From n = 4 [poly(3-butylthipene)] to n = 6 [poly(3-hexylthipene)], the miscibility between P3AT/PS blends decreased, but with further increase in the value of n, the miscibility increased. Thus, the miscibility of the P3HT/PS blend becomes the least among four blend pairs. This interesting phase behavior depending on n was successfully illustrated via the combination of Monte Carlo simulation and molecular dynamics.     

Effect of antioxidant activity and functional properties of Chingshey purple sweet potato fermented milk by Lactobacillus acidophilus, L. delbrueckii subsp. lactis, and L. gasseri strains

In this study, individual selected lactic acid bacteria strains Lactobacillus acidophilus (LA), L. delbrueckii subsp. lactis (LDL), and L. gasseri (LGA) were grown in Chingshey purple sweet potato (CPSP) substrate/media. CPSP is rich in anthocyanin, which possesses antioxidant activity and in vitro cell assay. The antioxidant ability and functional properties of the fermented milk were examined. High-performance liquid chromatographic (HPLC) method was used to analyze the free amino acid, organic acids, and anthocyanin content. Total phenolic compounds, scavenging effects of 1,1-diphenyl-2-picyl-hydrazyl (DPPH) radicals, and scavenging effects of superoxide anion radicals were determined to evaluate the antioxidant ability of the samples. The cell proliferation of the fermented PSP milk was evaluated by 3-(4,5-dimethyldiazol-2-yl)-2,5 diphenyl Tetrazolium Bromide (MTT) assay. The result indicated that the antioxidant ability of the fermented CPSP milk through LA, LDL, and LGA strains was significantly higher than CPSP. The main anthocyanins present in the samples are cyanidin and delphinidin. MTT assay has revealed that incubation with both PSP and fermented CPSP milk prevented the cell death of macrophage-like RAW264.7 cells. The potential health benefit of fermented PSP milk through LA, LDL, and LGA strains makes the further application of CPSP in health food highly worthwhile. PRACTICAL APPLICATION: (1) In our study, we have employed the γ-aminobutyric acid (GABA), organic acid contents, total phenol content, anthocyanins content, DPPH, oxygen radical absorbance capacity, superoxide dismutase activity assay, and cytotoxicity assay to assess the functional properties of fermented CPSP milk by different lactic acid bacteria. (2) Our results have revealed that the fermented CPSP milk samples possess high GABA concentrations, organic acid contents, anthocyanins contents, and antioxidant activity. This will provide potential opportunity to develop different functional food products from fermented CPSP milk. (3) The potential health benefit of fermented CPSP milk makes the further application of CPSP in health food highly worthwhile.     

Conductive Supramolecular Polymer Nanocomposites with Tunable Properties to Manipulate Cell Growth and Functions

Synthetic bioactive nanocomposites show great promise in biomedicine for use in tissue growth, wound healing and the potential for bioengineered skin substitutes. Hydrogen-bonded supramolecular polymers (3A-PCL) can be combined with graphite crystals to form graphite/3A-PCL composites with tunable physical properties. When used as a bioactive substrate for cell culture, graphite/3A-PCL composites have an extremely low cytotoxic activity on normal cells and a high structural stability in a medium with red blood cells. A series of in vitro studies demonstrated that the resulting composite substrates can efficiently interact with cell surfaces to promote the adhesion, migration, and proliferation of adherent cells, as well as rapid wound healing ability at the damaged cellular surface. Importantly, placing these substrates under an indirect current electric field at only 0.1 V leads to a marked acceleration in cell growth, a significant increase in total cell numbers, and a remarkable alteration in cell morphology. These results reveal a newly created system with great potential to provide an efficient route for the development of multifunctional bioactive substrates with unique electro-responsiveness to manipulate cell growth and functions.     

Relationship between extrusion condition and mechanical properties of FRPP

In this work, the relationship between extrusion condition and mechanical properties of glass-fiber-reinforced polypropylene (FRPP) was investigated. It was found that the extrusion flow rate was higher but the extrusion pressure was lower as the fiber content decreased. The flow rate and pressure were more temperature-sensitive at high screw speed. As for the mechanical strength of FRPP, the yield strength decreased with increasing the fiber content, but modulus and impact strength significantly increased with increasing the fiber content. The high screw speed did not affect the mechanical strength of PP, but decreased the strength of FRPP. At higher extrusion temperature, the yield strength and modulus of FRPP increased, but the impact strength decreased. The yield strength and modulus of extrudates along the longitudinal direction of extruder were always higher than those along other directions by the effect of fiber orientation. The specimens taken from different positions of extrudate would show different mechanical strength. The way of cooling for the extrudates would affect the mechanical properties of FRPP, too. All the above relations were discussed and well explained from the contribution of fiber distribution, fiber length, crystallinity of PP, and void content.