Advanced Materials Research Vols. 396-398

Abstract: The orthogonal experimental design was used to optimise Aspergillus niger enzyme-assisted extraction for flavonoids-enriched extract from Dicranopteris. The results indicate that the highest extraction ratio of flavonoids by Aspergillus niger enzyme-assisted extraction could arrive 13.67% using 30ml Aspergillus niger enzyme solution at 70°C,pH5.0 for 2h extraction, which was more efficient than that by without enzymes heating extraction.The flavonoids extract exhibited quite excellent inhibitions of hydroxyl radical. Meanwhile, it was found that the bioactivities appeared to be dose-dependent of flavonoids.

Abstract: A method of preparation and pilot scale production of Al-pillared montmorillonite has been developed. There is a minimum of time and amount of liquid. And it is simpler to operate than the conventional method of pillaring by using the commercial aluminium hydroxychloride(PAC) powder as the pillaring agent. Here, the effect of the major factors such as the mass ratio of PAC to montmorillonite, the concentration of montmorillonite slurry, the sodium agent pretreatment, washing times and drying temperature on the Al-pillared montmorillonite are studied. Then the optimal technical parameters is determined. XRD, BET surface area and micropore volume are applied in order to study the structure and properties of Al-pillared montmorillonite. As a result, the amplification experiment under the optimum conditions shows that this method offers the potential for extension to an industrial-scale process.

Abstract: Abstract: Purpose To search for an isolation method of grifolan synthase, and research grifolan synthase partly enzymatic properties. Methods Taking Grifola frondosa as material, the mycelium was broken by ultrasonic, and then centrifugated, the supernatant was collected, GS was precipitated by different concentrations of ethanol, ammonium sulfate and acetone, the suitable isolation method of GS was researched out by taking enzyme activity and protein content as parameters. Reducing sugar, protein content and total sugar content were determined respectively by using 3,5-dinitrosalicylic acid (DNS) method, Coomassie brilliant blue method and phenol-sulfuric acid method. Taking glucose as substrate, GS activity was reflected by the consumption of glucose. Consumption of glucose was measured by DNS method. The optimal temperature and pH of GS enzyme reaction was determined by carrying out the enzyme assay at different temperatures and pH levels.The acid-base stability of GS was determined by subjecting GS to different pH levels for 60 minutes, and the heat stability of GS was determined by subjecting GS to different temperatures for 30 minutes. The direction of GS enzymatic reaction was determined by measuring the consumption of β-glucan in 1 minute. The possibility of GS existing extracellular was judged by determining GS activity in extracellular fermentation liquor. Results The proper isolation method of GS is that the mycelium was collected from fermentation liquor and broken by ultrasonic for 1min, then centrifugated at 5000rpm for 10 minutes and a supernatant was collected. Ammonium sulfate was added to the concentration of 60%, and then centrifugated at 12000rpm for 10 minutes at 4°C, the pellets was collected as GS crude enzyme. Using this method, 93.86mg of crude enzyme which enzyme activity was 5700U/mg was obtained from 100g mycelium with moisture content of 87.28%, extraction rate of crude enzyme was 0.7379%. The optimum pH of GS enzyme reaction was pH=5.0 and the optimum temperature was 15°C, GS was most stable at pH=5.0 and in the range of 30 °C to 50 °C. Just 0.6996μg β-glucan was hydrolyzed in 1 minute by GS which can actually consume 5700μg glucose per minute in the synthetic reaction of β-glucan, considering the error in actual measurement, it can be considered that GS is a one-way enzyme that it can only catalyze the synthesis of β-glucan. GS activity in extracellular Grifola frondosa fermentation liquor was -0.1875U/ml, indicating that GS is one kind of intracellular enzyme and without GS activity in fermentation liquor or extracellular. Conclusion An isolation method of grifolan synthase form the mycelium of Grifola frondosa was researched out, and grifolan synthase partly enzymatic properties were studied in this paper. It can lay the foundation for the further study on the structure and function of GS and grifolan production.

Abstract: The aim of this work was to optimize a simultaneous distillation-extraction (SDE) procedure for the volatile compounds of black pepper (Piper Nigrum L.). Several variables that could potentially affect the extraction efficiency, namely, the liquid: solid ratio (volume per mass), soaking time and simultaneous distillation-extraction time have been optimized by means of response surface methodology (RSM). The optimum technology conditions have been attained by RSM as follows: the ratio of liquid to solid 25:1, simultaneous distillation-extraction time 3h and the soaking time 1.5h, under the optimum operating conditions, the extraction yield was 1.458%.

Abstract: Bleached wood pulp fibers grafted with polyacrylamide (PAM) was synthesized through surface-initiated atom transfer radical polymerization (SI-ATRP) to be applied in papermaking. The ATRP macroinitiator was prepared by esterification of hydroxyl groups of wood fibers with α-bromoisobutyryl bromide (α-BIBB). The bromine atoms on the surface of the macroinitiator were characterized and calculated by FT-IR, EDXS and TGA techniques. The ATRP grafting reaction conditions of fiber-PMA were discussed and determined. To optimize the polymerization in the CuBr/PMDETA catalytic system, several influencing factors on grafting yield were investigated, including solvent, reaction temperature, monomer concentration and sacrificial initiator. The PAM grafted fibers were characterized by FT-IR and TGA analyses.

Abstract: Anthocyanins, which possess strong antioxidant activities, are abundant in purple sweet potato wine. In the present study, changes in the antioxidant activity of purple sweet potato wine during storage were investigated. The results showed that purple sweet potato wine had high 2,2-dipheny-l-picrylhydrazyl (DPPH) free-radical and superoxide-radical scavenging activities, which were stable during storage periods. Compared with these two scavenging activities, the hydroxyl-radical scavenging activity of purple sweet potato wine was concentration-dependent and only presented relatively obvious scavenging activity at high concentrations. This hydroxyl-radical scavenging activity was also stabile during storage periods. The results are valuable in purple sweet potato wine research and development.

Abstract: This paper introduced a method to subside red mud slurry using a kind of mixed polyacrylamide (PAM) solutions which composed two different molecular weights (19×106 and 0.8×106). The mixing ratio and feeding method of the different PAMs were investigated. The results show that the sedimentation rate can be obviously increased when using polyacrylamide mixtures. The optimum PAM mixing ratio (19×106/0.8×106, v/v) is 8:2, and feeding them by adding the mixed PAM solution prepared in advance. In this way, the supernatant liquid height can be increased by 5% compared with that of using PAM of 0.8×106 alone, the settling time can be shortened by 31.9% compared with that of using PAM of 19×106 alone.

Abstract: Mutations of K-ras gene have been proven to play important roles in human tumor progression. Point mutations of K-ras gene located in codons 61 are gene hot spot mutation regions in patients with gastric cancer. A simple and effective capillary electrophoresis (CE) method for point mutation detection in codon 61 of K-ras gene was established. The polymerase chain reaction (PCR) fragments included codon 61 of K-ras gene were analyzed by single-strand conformation polymorphism (SSCP)-CE method. The CE analysis was performed by using a 1×Tris–borate–EDTA (TBE) buffer containing 3.0% (w/v) poly (ethylene oxide) (PEO) (MW 300 000) under reverse polarity with 15 oC and voltage of 15 kV. Forty-two gastric cancer patients were analyzed using this developed method. K-ras gene mutation was found in 17 cases (40.5 %) and the results showed that K-ras gene mutation in gastric cancer tissue is a usual event, and the SSCP-CE was feasible for mutation detection of K-ras gene in populations. Detection of gene mutation of gastric cancer tissue by PCR - SSCP has a certain value to diagnosis of gastric cancer and to prevent gastric cancer associated with clinical and pathological features, living habits of different patients by detection mutation of K-ras gene codon 61.

Abstract: A study to track and detect the variation of bioactive components in rosemary extraction solution and extracts, by adding organic acid synergists, such as citric acid, oxalic acid and tartaric acid, was performed using high performance liquid chromatography (HPLC). Ultrasound was also used to increase the extraction efficiency, improve the yields of rosemary extracts and shorten the extraction time. The experimental results showed that the content of the key bioactive component carnosic acid was easier to reduce during the storage of extraction solution and extracts, meanwhile, adding citric acid, oxalic acid and tartaric acid during the extraction could actually slow down the trend of the reduction of the bioactive components, especially for carnosic acid.

Abstract: Grafted chitosan(CTS) copolymer was synthesized by the aqueous solution polymerization method, using the ammonium persulfate as initiator graft, Acrylamide（AM）and methacrylamide trimethyl Ammonium Chloride (DMC) as the grafted monomer. The effects of reaction conditions on grafted copolymerization were studied. When the deacetylation degree of chitosan as raw material is 86%, the optimum reaction to produce CTS -AM-DMC ternary graft copolymers by first AM and then DMC sequence were obtained at [initiator] 0.08%, 50°Cand 3.5h.The structure of CTS-AM-DMC was characterized by FTIR and XRD. When the dosage of synthetic product is 0.3mg/L, the effect of flocculation on the papermaking wastewater is obvious better, which can make the light transmission up to 99%, and CODCr to 9mg/L.