Volatile and non-volatile compound profiles of commercial sweet pickled mango and its correlation with consumer preference

Sweet pickled mango named Ma-Muang Bao Chae-Im is a traditional preserved mango from Hat Yai, Thailand. This study investigated (I) volatile and non-volatile compound profiles of commercial Ma-Muang Bao Chae-Im and (II) their relationship to consumer preference. Untargeted metabolomics profiling was performed by gas chromatography-mass quadrupole-time of flight analysis. There were 117 volatile and 44 non-volatile compounds annotated in six commercial brands of Ma-Muang Bao Chae-Im. Furthermore, 46 volatile and 19 non-volatile compounds’ discriminant markers were found by Partial least square discriminant analysis. Among those markers, sorbic and benzoic acid were observed in several brands; moreover, the combination of both compounds altered the volatile profile, especially the ester group. Partial least square regression revealed that overall consumer liking is correlated to 1-heptanol; 1-octanol; acetoin; acetic acid, 2-phenylethyl ester; D-manitol; terpenes and terpenoids, while firmness to sucrose and L-(-)-sorbofuranose. On the other hand, most ester compounds were not related to consumer preference.     

Association Colloids Formed by Multiple Surface Active Minor Components and Their Effect on Lipid Oxidation in Bulk Oil

Association colloids formed by surface active minor components play an important role in the oxidative stability of bulk oils. To imitate the formation of nanostructures in refined oils, multiple surface active minor components including phospholipids, free fatty acids, diacylglycerols and sterols were added to stripped corn oil. The critical micelle concentration (CMC) of the mixed components was determined. The impact of mixed minor components at below and above their CMC on oxidative stability of bulk oil and on antioxidant activity of α-tocopherol and Trolox was investigated. The CMC of the mixed surface active components in bulk oil was 20 µmol/kg oil in the presence of 383 ± 2 ppm of water. 1,2-Dioleoyl-sn-glycero-3-phosphocholine (DOPC) played an important role on the formation of association colloids since it was the most important component in forming the association colloids as confirmed by CMC and fluorescence probe studies. The association colloids formed by the mixed components showed prooxidative activity in bulk oil as determined by monitoring the formation of lipid hydroperoxide and hexanal. The activity of α-tocopherol or Trolox was not changed by mixed components association colloids. These results suggest that association colloids both physically and chemically impacted the oxidative stability and activity of antioxidants in bulk oil.     

The Effect of Y<Subscript>2</Subscript>O<Subscript>3</Subscript> Buffer Layer on the Magnetic Properties of Melt-Processed YBCO Superconductor

In this study, two kinds of melt-processed YBCO samples (Y1050-1 and Y1050-2) grown on a buffer layer of Y₂O₃ addition were fabricated. The compacted powders were located on a crucible with Y₂O₃ powder freely poured and a buffer layer of pressed Y₂O₃ to avoid liquid to spread on the furnace plate. The superconducting transition temperature was determined by a standard four-point method at temperatures between 40 and 100 K. The transition temperatures of Y1050-1 and Y1050-2 were found to be 91.6 and 92.9 K at zero magnetic fields, respectively. The magnetization measurements were performed using a vibrating sample magnetometer (VSM) on the same system at 5, 40, and 77 K. The critical current densities for Y1050-1 and Y1050-2 samples were determined to be 6.5×10³ and 5.6×10³ A/cm² at 77 K in zero magnetic fields, respectively. The trapped magnetic field measurements of the samples were performed by using a Hall probe scanning device and a Fe–Nd–B permanent magnet at 77 K. It was found that the trapped magnetic field of the Y1050-1 sample is higher than that of the Y1050-2 sample.     

SArch for assessing environmental impact of Thai housing

This paper introduces SArch, an environmental impact assessment tool developed in Thailand. SArch can be used to assess the environmental impact of construction materials throughout the lifecycle of buildings. The assessment starts with the raw materials and follows their preparation, transportation, utilization and maintenance to post-utilization or destruction. Five categories of impact are considered: global warming, acidification, eutrophication, ecological toxicity and smog. SArch can be used to assess the environmental impact of materials in the building design phase as well as the impact of existing buildings. An example of using SArch for the assessment of a residential house in Thailand is provided.     

The Effect of Ionic Surfactant Adsorption on the Rheology of Ceramic Glaze Suspensions

The rheological behavior of ceramic glaze suspensions containing limestone, quartz, feldspar, and kaolin, has been improved by the addition of either a cationic (cetylpyridinium chloride, CPC) or an anionic (sodium dodecylbenzenesulfonate, SDBS) surfactant. Additional stability and lower viscosity can result from either electrical double layer repulsion or steric repulsion depending on the surfactant type, concentration, ionic strength, and pH. Underdosing may result in high viscosity due to charge neutrality and hydrophobic attraction between particles while overdosing may result in high viscosity possibly due to micelles in the solution. The situation is particularly complicated for glazes containing limestone and anionic surfactant at moderate to low pH where calcium carbonate is soluble. The anionic surfactant and calcium ions can form complexes that are poorly soluble and strongly adsorb to the surface of the particles. The resulting thick steric layer of complexes produces a significant repulsion and stable, low viscosity suspensions. ζ potential measurements and adsorption isotherms are used to interpret the rheological behavior.     

Facile synthesis of silver immobilized-poly(methyl methacrylate)/polyethyleneimine core–shell particle composites

A facile route to synthesize silver-embedded-poly(methyl methacrylate)/polyethyleneimine (PMMA/PEI-Ag) core–shell particle composites was illustrated in this present work. PMMA/PEI core–shell particle templates were first prepared by a surfactant-free emulsion polymerization. PEI on the templates' surface was further used to complex and reduce Ag⁺ ions (from silver nitrate solution) to silver nanoparticles (AgNPs) at ambient temperature, resulting in the PMMA/PEI-Ag particle composites. The formation of AgNPs was affected by the pHs of the reaction medium. The pH of reaction medium at 6.5 was optimal for the formation of PMMA/PEI-Ag with good colloidal stability, which was confirmed by size and size distribution, FTIR spectroscopy, UV–vis spectroscopy and X-ray diffraction. Moreover, the amount of AgNO₃ solution (4.17–12.50 g) was found to affect the formation of AgNPs. Transmission electron microscopy (TEM) indicated that the AgNPs were incorporated in the PMMA/PEI core–shell matrix, and had 6–10 nm in diameter. AgNPs immobilized on PMMA/PEI core–shell particles were also investigated by energy dispersive X-ray spectroscopy analysis mode extended from scanning electron microscopy (SEM/EDS). Furthermore, the presence of AgNPs was found to influence the thermal degradation behavior of PMMA/PEI particle composites as observed through thermogravimetric analysis (TGA).     

Continuously cast ductile iron: Processing, structures, and properties

Ductile iron billets were continuously cast using a horizontal casting machine. The billets were cast successfully, and the overall quality of the billets was acceptable. The as-cast microstructure consisted of eutectic carbide, chunky carbide and graphite nodules in a pearlite matrix. The amount of carbide was relatively large compared with that in traditional sand castings. Graphite nodularity decreased as the melt was held for longer periods of time before casting after inoculation and nodularisation treatments. The fading effect was significant when the melt was held for 6 min and longer. Graphite nodularity was found to affect the tensile strength and elongation, but not hardness, of the billets. The surface quality of the billets was fair, although light waves and drawal marks were clearly visible. The billets had good roundness. The tensile strength was found to be between 410 and 550 MPa; the elongation was 2.5-4.0%; and the hardness was 520-550 HB. Possible approaches to improving the as-cast structure and the implications of this research are discussed.     

What Makes Good Antioxidants in Lipid-Based Systems? The Next Theories Beyond the Polar Paradox

The polar paradox states that polar antioxidants are more active in bulk lipids than their nonpolar counterparts, whereas nonpolar antioxidants are more effective in oil-in-water emulsion than their polar homologs. However, recent results, showing that not all antioxidants behave in a manner proposed by this hypothesis in oil and emulsion, lead us to revisit the polar paradox and to put forward new concepts, hypotheses, and theories. In bulk oil, new evidences have been brought to demonstrate that the crucial site of oxidation is not the air-oil interface, as postulated by the polar paradox, but association colloids formed with traces of water and surface active molecules such as phospholipids. The role of these association colloids on lipid oxidation and its inhibition by antioxidant is also addressed as well as the complex influence of the hydrophobicity on the ability of antioxidants to protect lipids from oxidation. In oil-in water emulsion, we have covered the recently discovered non linear (or cut-off) influence of the hydrophobicity on antioxidant capacity. For the first time, different mechanisms of action are formulated in details to try to account for this nonlinear effect. As suggested by the great amount of biological studies showing a cut-off effect, this phenomenon could be widespread in dispersed lipid systems including emulsions and liposomes as well as in living systems such as cultured cells. Works on the cut-off effect paves the way for the determination of the critical chain length which corresponds to the threshold beyond which antioxidant capacity suddenly collapses. The systematic search for this new physico-chemical parameter will allow designing novel phenolipids and other amphiphilic antioxidants in a rational fashion. Finally, in both bulk oils and emulsions, we feel that it is now time for a paradigm shift from the polar paradox to the next theories.     

Comparison of Antioxidant Capacities of Rosmarinate Alkyl Esters in Riboflavin Photosensitized Oil-in-Water Emulsions

Effects of the alkyl chain length of rosmarinate alkyl esters on the oxidative stability in photosensitized oil-in-water (O/W) emulsions were determined by lipid hydroperoxides and headspace volatile analyses. Antioxidant capacities of 20 μM rosmarinate esters with alkyl chain length of 0, 4, 8, 12, 18, and 20 were tested in O/W emulsion containing stripped soybean oil, Tween 20 as an emulsifier, and riboflavin as a photosensitizer. Synergistic or antagonistic effects of 20 μM α-tocopherol in the presence of rosmarinate alkyl esters were also determined. Samples containing rosmarinate with 4 and 8 alkyl esters showed lower lipid hydroperoxides and headspace volatiles than those without rosmarinate and those with 0, 12, 18, and 20 alkyl esters, which indicates that phenolic free radical scavengers showed antioxidant capacities non-linearly in riboflavin photosensitized O/W emulsions. Antagonistic rather than synergistic effects were observed in all rosmarinate alkyl esters with α-tocopherol in current conditions although rosmarinates with 4, 8, and 12 alkyl esters showed better antioxidant capacities than those with other alkyl chain length. The results of this study clearly showed that rosmarinates need the proper length of non-polar groups to show optimum antioxidant capacities in O/W emulsions with Tween 20 as an emulsifier under riboflavin photosensitization.     

Core/shell polymethyl methacrylate/polyethyleneimine particles incorporating large amounts of iron oxide nanoparticles prepared by emulsifier-free emulsion polymerization

A facile synthetic route for the preparation of magnetic poly(methyl methacrylate) (PMMA) core/polyethyleneimine (PEI) shell colloidal particles, possessing high saturation magnetization is reported. Bilayer oleic acid-stabilized iron oxide nanoparticles (bIOs) were designed to have both favorable encapsulation of iron oxide nanoparticles and interaction with protonated amine groups of PEI. The prepared particles had diameter ranging from 180 to 207 nm with narrow size distribution and displayed highly positive surface charges up to +47 mV. TEM revealed that the well-defined bIOs were successfully encapsulated inside the polymer core–shell colloids. Thermogravimetric analysis and magnetization study indicated that these colloidal particles had the magnetic material up to 80 wt % loading and exhibited superparamagnetic property with high saturation magnetization. Thus, they could be potentially useful in various applications, including magnetic separation, medical diagnostics, or drug delivery.