Effects of newly developed waxy rice flour on the quality characteristics and oxidative stability of Korean traditional fried cookie, <Emphasis Type="Italic">Yakgwa</Emphasis>

The effects of waxy rice flour (WRF) in substitution for wheat flour (WF) on the oil absorption, structure, texture and oxidative stability of traditional Korean fried cookies, Yakgwa, were investigated. Fried cookie prepared with WF showed the greatest oil absorption (20.66%), however, the oil absorption reduced as the ratio of WRF substitution increased. The fried cookies prepared with WRF in substitution for WR showed the reduced oil absorption and increased oxidation stability. In addition, the cookies still maintained a layered structure with crispiness and softness. Also, when white WRF was used, the fried cookie showed the increased oxidative stability and reduced oil absorption decreased compared to when brown WRF was used. WRF can be used as a substitute for WF at a percentage of up to 75% and can improve the structure and oxidative stability of Yakgwa during storage. Substitution of WRF for WF significantly improves the structure and oxidative stability of Yakgwa.     

Determination of acetaldehyde,methanol and fusel oils in distilled liquors and sakès by headspace gas chromatography

Food Science and Biotechnology - In this study, a headspace gas chromatography (HS-GC) method was carried out to determine the contents of acetaldehyde, methanol and fusel oils in distilled liquors...     

Three-parameter empirical isotherm model: its application to sorption onto organoclays

A new three-parameter empirical isotherm model (the Song isotherm model, hereinafter) is proposed. This model satisfies the Henry's law and the Freundlich isotherm model in the low and high concentration ranges, respectively. We applied this model to the single-solute sorption of 2-chloro-, 3-cyano-, and 4-nitrophenol from water to montmorillonites organically modified with either hexadecyltrimethylammonium (HDTMA) cation or both HDTMA and tetramethylammonium (TMA) dual cations. Sorption to organoclays (i.e., organically modified clays) modified with the long-hydrocarbon chain organic cations or the short- and long-hydrocarbon chain dual organic cations usually occurs by a partition mechanism. Sorption of polar organic compounds to organoclays, however, becomes nonlinear when the solution-phase concentration covered is more than 3 orders of magnitude. The three parameters contained in the presently proposed model could be estimated from the plot, log(q/c) versus log c. The partition coefficient in the Henry's law region (K) can be estimated from the ordinate value of the asymptote in the low concentration region, the Freundlich index (n) can be estimated from the slope of the asymptote in the high concentration region, and the parameter (beta) corresponding to the crossover point can be estimated from the intersection point of the two asymptotes. By performing nonlinear curve fitting to the raw data, q versus c, using the initial guesses estimated from the manipulated data, log-(q/c) versus log c, the optimum set of parameters could be determined without worrying much over the annoying local minima. The Song model was compared with other existing two- and three-parameter isotherm models. The Song model fitted our experimental data better than the Langmuir and Freundlich models and showed nearly the same goodness-of-fit as the Redlich-Peterson and dual-mode models. The obvious merit of the Song model is that it provides us with the partition coefficient in the Henry's law region. The organic carbon-normalized partition coefficients in the Henry's law region were found to be about 1 order of magnitude higher than the corresponding octanol-water partition coefficients, at least for the phenolic compounds covered in this study.     

Antioxidant capacity of decarboxylated rice bran extract in bulk oil

Decarboxylation of ferulic acid would increase the solubility in oils. Rice bran extract (RBE) containing 29 mg ferulic acid/g RBE was decarboxylated to obtain decarboxylated rice bran extract (DRBE), and its antioxidant capacity in oil system was studied. After addition of DRBE (500 ppm), oxidation was monitored for 20 days at 60 °C under the dark. To compare the oxidation degree, 500 ppm of ferulic acid and well-known lipid soluble antioxidant, α-tocopherol, were used. Contents of conjugated dienes and aldehydes were measured using ¹H NMR as well as peroxide value (POV). On 7 days of oxidation, DRBE (539.0 meq/kg oil) showed lower POV than the control (819.7 meq/kg oil). Also, contents of total conjugated form and aldehydes were 194.60, and 5.94 mmol/L oil, which were lower than those of control (323.63 and 15.94 mmol/L oil). However, after 10 days of oxidation, antioxidant capacity of DRBE was not observed.     

Fabrication of highly electrical synthetic leather with polyurethane/poly(3,4-ethylene dioxythiophene)/poly(styrene sulfonate)

Poly(ethylene-3,4-dioxythiophene)/poly(styrene sulfonic acid)(PEDOT/PSS) water dispersions are commercially available, and various coating formulations for substrates, such as glass, plastics, and ceramics, have been suggested. Recently, it was found that the addition of a small amount of organic solvent, such as ethylene glycol (EG) and dimethylsulfoxide (DMSO), to the aqueous dispersion of PEDOT/PSS increases the conductivity significantly. This study examined how a combination of solvent addition affects the PEDOT/PSS conductivity of artificial leather (napping fabric with short fur). In addition, the sustainability of the PEDOT/PSS conductivity for the common use of artificial leather was investigated using abrasion and tension cycle tests. The electric conductivity of the leather increased in the order of EG < DMSO < EG + DMSO. The sustainability of the PEDOT/PSS conductivity in the case of EG + DMSO was superior to that of the EG or DMSO solvents. The padding process was found to be a more effective method for achieving durability against abrasion and tension cycle with a lower deposit weight than when using the coating process. The mechanical properties of the synthetic leather using the padding process also showed high performance compared to the coating process.     

Highly active and stable electrocatalytic transition metal phosphides (Ni2P and FeP) nanoparticles on porous carbon cloth for overall water splitting at high current density

Highly active and stable hydrogen production at high current densities is required for practical application of electrocatalytic water splitting. In this study, highly active self-supporting electrodes with excellent durability were designed and developed for high-performance overall water splitting at a high current density. First, a colloid-based dip-coating method using porous carbon cloth (PCC) was introduced to obtain uniformly coated Ni and Fe nanoparticles on a conductive substrate. Then, the desired phase transitions of Ni and Fe to Ni₂P and FeP, respectively, proceeded by thermal phosphidation at optimum temperature. The uniformly interconnected Ni₂P layers on the PCC substrate (Ni₂P@PCC) and FeP layers on the PCC substrate (FeP@PCC) exhibited outstanding oxygen and hydrogen evolution reactions, respectively. When each electrode was adopted as an anode and a cathode for the overall water splitting cell, excellent performance was achieved, with a low operational voltage of 1.76 V and high durability for 100 hours at a high current density of 50 mA cm⁻².     

Evaluation of polycyclic aromatic hydrocarbon contents and risk assessment for infant formula in Korea

This study analyzed polycyclic aromatic hydrocarbons (PAHs) reported to be carcinogenic and listed by the International Agency for Research on Cancer (IARC) as group 1 to 3. Liquid-liquid extraction and HPLC-FLD were used to for the analysis and detection of the 7 PAHs. The average concentrations of total PAHs were 0.435 and 0.457 μg/kg in infant formulas and mixed milk powders, respectively. Furthermore, BaP contents were much lower than 1 μg/kg, the maximum tolerable limit reported by the Commission Regulation. PAH contents were converted to BaP to conduct exposure assessment and risk characterization. Dietary exposure was in the range of 0.037 to 0.073 ng-TEQ_BaP/kg/day. Margin of exposure (MOE) was from 1,370,000 to 2,700,000, which is of negligible concern.