Advanced Materials Research Vols. 807-809

Abstract: Okara protein isolate was hydrolyzed by two stages enzyme hydrolysis (Protamex+Flavourzyme, Pro+Fla ) and further separated by sequential ultrafiltration (UF) to four fractions (P1~P4). The 2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) scavenging activity of the P3 fraction (1kDa < MW < 3kDa) is 24.6 mmol trolox equivalent (TE)/g peptide and the inhibitory activity is 84.2% at 10 mg/mL. The hydroxyl radical scavenging activity is 85.4% at the same concentration. Pro+Fla-P3 was incorporated into ground beef to determine their effect on lipid oxidation during a 15-day storage period. Pro+Fla-P3 fraction at 500 μg/g significantly inhibited lipid oxidation by 20.8% and 18.2% at day 8 and 15 of storage. The concentration at 250 μg/g could not significantly inhibit lipid oxidation at 15 day. It suggests that okara protein hydrolysates could be developed and used to improve shelf-life of meat products.

Abstract: The effects of inter-trial interval on the stability of odor perceived intensity has been investigated in this paper. One min, three min and five min were set as intervals and the results showed that odor perceived intensities in the replicate experiments are relative stable when inter-trial interval is 1 min or 5 min. With a fixed inter-trial interval, the odor quality and odor intensity level have no significant effect on the variability of the odor perceived intensity; whereas, the variability of the perceived intensity is related to the odor quality at different inter-trial interval.

Abstract: The amount of sample can enter the nasal cavity depends on the physiochemical characteristics such as distribution, volatility and solubility. It can be suspected that the difference of odor detection threshold (ODT) measured by different methods is related to the physicochemical properties of compounds. To investigate the relationship between ODT differences and the physicochemical properties of compounds, ODT values of four series of organic compounds were measured by triangle odor bag method and gas chromatography and olfactometry method; the results were compared and the absolute differences were calculated. Relationship between ODT differences and the type of functional group and some of the physicochemical properties of compounds was analyzed. The results showed the type of functional group had significant effect on the differences. Certain linear relationships between the logarithmic value of differences and the logarithmic values of saturated vapor pressure and molecular weight were observed.

Abstract: The paper presents a novel method for the separation/enrichment of trace Cu²⁺ using microcrystalline phenolphthalein loaded with cupferron (Cup) prior to the determination by spectrophoto- metry. The effects of different parameters,such as the dosages of phenolphthalein and Cup and acidity on the enrichment yield of Cu²⁺ have been investigated to select the experimental conditions. The possible enrichment mechanism of Cu²⁺ was discussed.The results showed that under the optimum conditions, Cu²⁺ could be quantificationally adsorbed on the surface of microcrystalline phenolphthalein in the form of the chelate precipitate of Cu (Cup)₂ ,while Ni²⁺,Zn²⁺,Mn²⁺,Fe²⁺ and Al³⁺ could not be adsorbed at all.Therefore,Cu²⁺ was completely separated from the above metal ions in the solution. The quantitative separation/enrichment and determination of Cu²⁺ in various environmental water samples was performed, and the results agreed well with those obtained by FAAS method.

Abstract: A new Cd (II) ion-imprinted polymer (Cd (II)-IIP), which can be used for selective adsorption of Cd (II) from aqueous solutions, was successfully prepared based on silica gel particles with the help of surface molecular imprinting technology. The adsorption kinetic curve, adsorption isotherm and selective adsorption were measured by static method. The adsorption kinetics of IIPs for Cd (II) reached the equilibrium at about 10 min. The maximum adsorption capacity was 29.36 mg/g, and the IIPs had much higher adsorption quantity than NIPs. Competitive adsorption studies showed that Cd (II)-IIP offers the advantages of selectivity toward targeted Cd (II) compared with NIP in the presence other metal ions. The results showed that the IIPs possessed good specific adsorption capacity and selectivity for Cd (II).

Abstract: This study evaluated and optimized the UV/ chlorine process for natural organic matters (NOMs) removal using response surface methodology (RSM). The effects of both the primary and secondary interactions of the reaction variables, including initial chlorine concentration (X₁), UV radiation time (X₂) and pH value (X₃), were examined. A satisfactory prediction response model (R²=0.999) was obtained, indicating the reliability of the methodology. The optimum condition obtained by CCD were 4.5 mg·L^-1 initial chlorine concentration, 7 min UV radiation time and pH 6.7. Under the optical condition, the maximum TOC removal was 48% and TOC concentration was only 2.6 mg·L^-1. The UV/ chlorine process as a novel AOP has many advantages for drinking water treatment, in terms of less chemical consumption, shorter reaction time and simpler technology.

Abstract: Proteins were the primary organics of excess sludge. Their properties were related to pH, which in turn affected the production of volatile fatty acids (VFAs). Excess sludge was firstly pretreated using the thermo-alkaline method, and the centrifuged supernatant was then taken as the substrate to investigate the effect of pH on the accumulation of VFAs from proteinaceous waste. The heating method was used to treat the inoculums in order to inhibit the generation of bio-methane during the whole anaerobic fermentation. The results showed that pH had an obvious influence on the bioconversion of proteins. Although the conversion ratios were higher than 50% when pH was controlled at 7.0-11.0, the protein biodegradation was sensitive to too low or too high pH values. Soluble proteins were precipitated to become insoluble proteins with the adjustment of pH from alkaline to acid except at pH 3.0. Acetic acid was the main accumulated end-product at most of pH settings, and at pH 10.0, its concentration reached the maximum of 5.7 g·L^-1 which was around 57.8% of total VFAs. At various pHs, it was soluble proteins that were responsible for VFAs production, while the precipitated proteins displayed a poor bio-degradability and disfavored the accumulation of VFAs during a 240 h of anaerobic fermentation.

Abstract: In this study, the effect of operating parameters and the co-existing ions on the phosphate removal during the ferrous iron oxidation was investigated. Results showed that with the increase of DO and [Fe (II)]₀, the final phosphate removal rate both increased. But with increasing of pH, the final phosphate removal rate firstly increased and then decreased when the pH was higher than 8.0. The co-existing ions affected the final removal rate significantly, and the kinetics of phosphate removal followed the pseudo-first-order kinetic model. The corresponding k_obs trends for the cation followed the order of Cu²⁺>Mn²⁺>Zn²⁺>NH⁴⁺-N. The presence of Cu²⁺ promoted the phosphate removal significantly. Compared with the control, , the time required to achieve 40 % phosphate removal rate, at the condition of 0.5 mg/L Cu²⁺, reduced from 60 min to 10 s. However, the selective anions inhibited the phosphate removal, due to the formation of Fe-anions complexes. The effect of selective anions on the phosphate removal rate constant decreased in the order of SO₄^2->Cl^-> NO₃^-.

Abstract: An investigation on the effects of humic acid (representing NOM) on TCE (a typical organic contaminant) removal by Fe⁰ in batch settings was carried out. Inhibitory effects of humic acid on Fe⁰ towards TCE removal were observed. At early stage of the experiments, humic acid might partition with TCE, and the adsorption or deposition of humic acid onto Fe⁰ surface would further facilitated TCE immobilization. Once the reduction reactive sites on Fe⁰ surfaces were covered by accumulated humic acid and the partition of TCE to humic acid became saturated, TCE removal in Fe⁰ was observed retarded.

Abstract: With Ti (C₄H₉O)₄ as raw material, and with untreated CNT, carboxylated CNT, hydroxylated CNT and carbon fiber as carriers respectively, four kinds of TiO₂-CNT composites were successful prepared orderly under the calcinated conditions of 400 to 800 °C by sol-gel method. The morphology and structure features of these composites were characterized by scanning calorimeter (DSC), X-ray diffraction (XRD) and scanning electron microscope (SEM) respectively. The results indicate that, as coexisting carrier material, the carbon nanotube had obvious effects on the morphology and structure of TiO₂ nanocrystal. However, when being carboxylated or hydroxylated, though multi-walled carbon nanotube has still obvious effects on crystalline form of TiO₂,threre are no remarkable impacts on its morphology.