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1.
Growth stress is important to achieve upright growth and avoid exterior influence on living trees. However, many problems are also triggered by the release of growth stress during wood processing, such as end split of log, distortion of board and inaccurate sawing. In order to evaluate the possibility of these problems to occur in poplar clone 107, a new breeding poplar clone in China, surface longitudinal growth strain (SLGS) and internal longitudinal growth strain (ILGS) both of straight and inclined trees were measured for depicting distributing patterns of growth strain both in peripheral and radial directions. Besides that, according to one-way ANOVA analysis, individual tree and peripheral position have a significant effect on SLGS in inclined trees, whereas such effect is insignificant in straight trees. Fiber morphology and shrinkage of wood sample beneath the SLGS testing positions were determined to illustrate the relationships between these properties with SLGS. The results suggested that growth stress is a poor indicator of fiber morphology and wood shrinkage properties for straight trees but a good one for inclined trees. Both the positive SLGS and ILGS are unexpectedly found at the opposite wood side of inclined trees. It is speculated that when the reorientation of inclined trees is insufficiently supported by exerting tensile stress at tension wood side, compressive stress will be formed at the opposite wood side as a complement.  相似文献   

2.
This study was designed to characterize a β-glucosidase from Oenococcus oeni 31MBR, a strain widely used in Chinese winemaking. An intracellular β-glucosidase (EC 3.2.1.21) was partially purified using a combination of ammonium sulfate precipitation and chromatographic methods. A single band was obtained in SDS-PAGE electrophoresis, indicating that the enzyme was highly purified and had an estimated molecular mass of 38.9 kDa. The enzyme exhibited highest activity at pH 4.5–5.0. The optimum temperature was 45 °C. Ethanol promoted the activity of this enzyme up to three times. Among the several metal ions assayed, only Mn2+ exhibited a partial promotion effect. The K m and V max values for p-nitrophenyl-β-d-glucopyranoside were 1.05 mmol/L and 0.957 nmol/min, respectively. Up to now, this study contains the first characterization of a native β-glucosidase purified from crude extracts of O. oeni 31MBR.  相似文献   

3.
Wood anatomy, physical and mechanical properties and decay resistance of the monocotyledon Dracaena mannii Baker from the Central African Republic were determined and compared with the wood of two dicotyledons of the comparable density. Despite of the completely different anatomical structure the mechanical properties of Dracaena are comparable to the dicotyledonous wood of comparable density. As opposed to mechanical properties the radial and tangential shrinkage in Dracaena is twice as great as in dicots of comparable density and the ratio of tangential to radial shrinkage is almost 3:1.  相似文献   

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Fresh ginseng was irradiated with 60Co-γ or an electron beam at the dose of 2 and 4 kGy and stored at 2 °C. The quality of ginseng was evaluated after 60 and 120 days. Results suggest that when the storage time was 120 days, 2 kGy EI-treated ginseng had the lowest decay rate. During the 2 storage periods, the amounts of most of 9 ginsenosides decreased with an increase in the irradiation dose. The total saponin content of both 60Co-γ-irradiated and EI-treated samples decreased with an increase in the irradiation dose. Significant (P <?0.05) upregulation of total polysaccharide content was observed in the 4 kGy EI samples after storage. Samples irradiated at 2 or 4 kGy by electron beam irradiation had the highest concentration of total saponin and ginseng polysaccharides, respectively. Levels of most of 17 amino acids decreased with the increasing irradiation dose. Exposure to irradiation doses up to 4 kGy affected the amino acid content of fresh ginseng. Ginseng irradiated at 4 kGy by 60Co-γ irradiation and stored for 120 days had a significantly higher activity of superoxide dismutase (P <?0.05). A significant difference was observed in the total concentration of nucleosides and nucleobases between irradiated and un-irradiated ginseng samples (P <?0.05). These data suggest that the combination of a lower irradiation dose and low temperature is an optimal condition for extending the shelf-life of fresh ginseng without detriment to its ingredients.  相似文献   

6.
In this study, different solvent extracts of skullcap (Scutellaria baicalensis) were assayed for their total phenol content (TPC), antioxidant activity [determined as DPPH radical scavenging activity, superoxide dismutase (SOD)-like activity, oxygen radical absorbance capacity (ORAC) assay, and comet assay], and α-glucosidaseinhibitory activity. The TPC of skullcap ranged from 9.06 mg/g gallic acid equivalents (GAE) for acetone extract (AE) to 91.8 mg/g GAE for methanol extract (ME). AE, which had a low TPC, exhibited the highest DPPH radical scavenging activity and SOD-like activity. TPC positively correlated with the ORAC assay (r=0.96, p<0.001). All skullcap extracts significantly reduced the hydrogen peroxide-induced DNA damage in human leukocytes. ME with a high TPC and ORAC value showed the highest α-glucosidase inhibition. The difference in the biological activities of the extracts may be due to the differences in their chemical structure or polarity. Therefore, the results obtained indicate that might be a potential source of compounds with health-protective effects. ME, in particular, might be a prospective therapeutic agent for diabetes.  相似文献   

7.
Origanum × majoricum Cambess. is the most commonly grown oregano in Argentina. The aim of this work was to explore and describe its polyphenolic profile by high-performance liquid chromatography with diode array detection (HPLC-DAD) to support identification by classical microscopy. Remarkable homogeneity was found when defining the HPLC-DAD fingerprint with 17 characteristic common peaks. Eleven spectroscopically identified compounds were located. The method was successfully applied for the characterization of 22 samples from different productive regions of Argentina. The genetic inheritance from both progenitors of this hybrid oregano was evidenced by the presence of compounds coming from Origanum majorana L. and Origanum vulgare L. This method, combined with statistical multivariate analysis, was also useful to recognize two groups within the samples. Although O. × majoricum Cambess. must be considered the only hybrid between two species, two origins considering the subspecies level of O. vulgare L. have been morphologically differentiated for the hybrid, both with O. majorana L. These formulas were differentiated by their HPLC-DAD fingerprints. The Argentine hybrids studied appeared consistently grouped under these two profiles.  相似文献   

8.
To investigate the influence of moisture content (MC) and steaming temperature on defects developing during steaming prior to kiln drying, mass loss, heat transfer, microstructures, extractives, and chemical transformation of Eucalyptus grandis?×?E. urophylla specimens (with moisture content of 120, 70, 60, 50, 40, 30, 20%) were observed in this study. Specimens of each experimental moisture content were steamed at 80, 100, and 120?°C for 4 h after pre-heating at atmospheric pressure, respectively. Results revealed that it was most beneficial to conduct steaming at 100?°C when the moisture content was approximately 50% after air drying when stagewise heating-up and continuous steaming schedule were adopted. Under this condition, there was a notable decrease in defects including edge bends, surface splits, and inner splits. Steaming was also a drying period characterized by various extents of mass loss. Changes in microstructures and extractive contents proved the increasing permeability of steamed wood. Deacetylation and crosslinking reactions happened in the hemicellulose of the sample materials, which contributed to the loss of hemicellulose after treatment.  相似文献   

9.
Extracellular and intracellular α-galactosidases were produced by yeast Debaryomyces hansenii UFV-1 grown on different media with several carbon sources. D. hansenii grown in YP-medium (1% yeast extract and 2% peptone) presented maximum cell mass (8.45 mg/mL) after 36 h of cultivation, with lactose as carbon source, followed by sucrose, glucose, raffinose, and galactose. Higher extracellular and intracellular α-galactosidases activities were observed at 48 h of D. hansenii cultivation in YPmedium containing galactose (0.97 and 5.27 U/mL) and lactose (1.28 and 4.88 U/mL), supporting the evidence for the model of induction for the yeast GAL/MEL regulon, such as described in Sacharomyces cereviseae.  相似文献   

10.
The present study revealed that the nutritive value of grape seeds (Vitis vinifera L.) was 383.55±0.13 Kcal/100 g, with magnesium as the most abundant mineral element (70.44±0.88 mg/L). The maximum phenolic (392.58±1.70mg of GAE/g), flavonoid (256.16±1.60 mg of QE/g), and tannin (30.95±0.17mg of CE/g) contents were also found in the ethanol, dichloromethane, and hexane extracts, respectively. The major phytochemical compounds in the ethyl acetate extract were identified via gas chromatography–mass spectrometry (GC–MS) analysis. The ethanol extract has the highest antioxidant activity (IC50=140±1.20 μg/mL for DPPH, 145.28±0.45mg α-tocopherol/g for total antioxidant capacity, and EC50=80±1.41 μg/mL for ferric-reducing power assays). For β-carotene test, the highest antioxidant activity was obtained in the hexane extract. A satisfactory antimicrobial activity was found against a panel of microorganisms with the ethyl acetate extract as the best antimicrobial agent. Additionally, it was found that the bactericidal concentration required for the grape seed extract to kill Listeria monocytogenes should be less than 12.50 mg/mL (minimum inhibitory concentration=4).  相似文献   

11.
The effect of irradiation (0–20 kGy) on hemp and sunflower seeds was assessed, with specific reference to the oxidatively labile lipid component (unsaturated fatty acids and tocochromanols). Total protein, lipid, and solids content of the seeds did not vary with irradiation dose. Lipid hydroperoxide concentration increased significantly in the sunflower seeds (48 mmol kg−1 lipid) and a significant increase in volatile secondary oxidation products was measured in both seeds (e.g. hexanal, heptanal, 1-penten-3-ol) with increasing irradiation dose. Irradiation at 5 kGy sterilised the seeds of all microbial contamination and irradiation doses of 20 kGy prevented germination. A loss of the antioxidant tocopherol was shown with increasing irradiation doses, although this was selective for specific tocopherol isoforms (α-tocopherol, β-tocopherol and γ-tocopherol).  相似文献   

12.
Some dietary supplements used to control overweight are based on protein concentrates from Phaseolus vulgaris, or kidney bean, known to contain high levels of α-amylase inhibitor, which may reduce the adsorption and prevent the digestion of carbohydrates. These concentrates of kidney bean also contain significant levels of antinutritional factors such as lectins and trypsin inhibitors. In recent years the concentrates of kidney bean have been processed to inactivate lectins and trypsin-inhibitor activity while preserving substantial α-amylase inhibitor activity. The aim of this study was to investigate and to compare the activity of the α-amylase inhibitor in some commercial supplements, and to determine the levels of residual lectins and trypsin inhibitors. The results show that the technological treatment used to reduce the levels of lectins and trypsin inhibitors partially decreases the activity of the amylase inhibitor. This study suggests the need for better standardization of the technological treatment of protein concentrates to ensure both the efficacy and safety of these dietary supplements.  相似文献   

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14.
This study aimed to develop and optimize a β-cyclodextrin (β-CD)-based technique for extracting anthocyanins from Lycium ruthenicum Murr. and to establish a ultra-high-performance liquid chromatography-diode array detector (UPLC-DAD) method for their analysis. β-CD solutions produced higher extraction yields of petunidin-3-O-(trans-p-coumaroyl)-rutinoside-5-O-glucoside and total anthocyanins from L. ruthenicum fruit than did pure water and aqueous hydroxypropyl-β-cyclodextrin (HPβ-CD) and ethanol and methanol solutions. Extraction at 50 °C for 30 min using 1.65% β-CD solution and a liquid/solid ratio of 15:1 produced the optimal extraction yield of L. ruthenicum anthocyanins. A UPLC-DAD method was developed for the determination of L. ruthenicum anthocyanins using an ethanol-based mobile phase, and the primary anthocyanins were identified using two-dimensional LC-MS/MS. Method validation showed that the developed method was accurate, stable, and reliable for the analysis of petunidin-3-O-(trans-p-coumaroyl)-rutinoside-5-O-glucoside and total anthocyanins from L. ruthenicum fruit. The present study showed that β-CD-based extraction coupled with UPLC-DAD analysis is an efficient and green method for the extraction and analysis of anthocyanins from L. ruthenicum fruit.  相似文献   

15.
This study investigated acceptability and consumer segmentation of soy sauce and famous Korean dish, bulgogi. A total of 123 participants evaluated intensity of 18 attributes and sensory liking of 4 commercial soy sauce samples and bulgogi samples made by aforementioned soy sauces. The overall results showed that appearance liking was the only significant different attribute among soy sauce samples and there were no significant differences among bulgogi samples. Furthermore, there was little correlation between overall liking of soy sauce and bulgogi samples. However, different segments of consumer groups were found by cluster analysis. Four and five subgroups of consumers were identified on evaluation of soy sauce samples and bulgogi samples, respectively. These results demonstrated that consumers’ different preference pattern. In conclusion, this study specified characteristics of commercial soy sauce perceived by consumers and consumers’ acceptability toward soy sauces and bulgogi made using soy sauces.  相似文献   

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An acryloyl β-cyclodextrin (A-β-CD) monolithic column for solid-phase microextraction (SPME) and determination of carbofuran and carbaryl by high-performance liquid chromatography (HPLC) have been prepared through a “one-step” polymerization method. The synthesis conditions, including the volume of cross-linker, the ratio and volume of mixed porogenic solvent consisted of methanol and N,N-dimethylformamide were optimized. The prepared monolithic column was characterized by thermogravimeteric analysis (TGA), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and Brunner-Emmet-Teller (BET) measurement. The eluent type, volume and flow rate, sample volume, flow rate, acidity, and ionic strength were optimized in detail. Under the optimized conditions, a simple, rapid, and sensitive SPME-HPLC method was developed for determination of carbofuran and carbaryl in rice samples. The method yielded a linear calibration curve in the concentration ranges of 1.5–200 μg/kg for carbofuran and 0.3–200 μg/kg for carbaryl with correlation coefficients (R 2) of above 0.9955. Limits of detection (S/N = 3) were 0.5 μg/kg for carbofuran and 0.1 μg/kg for carbaryl, respectively. The recoveries of this method ranged from 88.1 to 105.8%. The relative standard deviations were less than 8.1%.  相似文献   

18.
Ecklonia cava (EC) was irradiated with γ-rays at doses of 3, 7, and 20 kGy. The extraction yields, total polyphenol content (TPC), DPPH radical scavenging activity, antimicrobial activity, and color of the EC extracts were assessed. The results showed that irradiation caused an increase in the extraction yields of ethanol and water. TPC was found to be significantly increased when EC powder was subjected to irradiation, followed by ethanol and water extraction. However, DPPH radical scavenging and antimicrobial activities were stable under all irradiation conditions. In the heat and pH stability tests, the DPPH radical scavenging activities of EC ethanol extracts were not influenced by irradiation. Irradiation caused an increase in the lightness and redness of EC extracts and decreased the yellowness. In conclusion, γ-irradiation increased the extraction yield and TPC and brightened the color, while maintaining the antioxidant and antimicrobial activities.  相似文献   

19.
The aim of this work was to carry out the physicochemical and functional characterization of the purified galactomannan obtained from mesquite seed’s endosperm (MSG). From the seeds, a MSG content of 13/100 g with a purity of 94/100 g was determined. The dispersions of MSG samples (up to 5 g/100 mL) exhibited a shear thinning non-Newtonian behavior, with 35.68 mPa.s of viscosity, and surface tension values between 43.5 and 61.06 dynes/cm. The chromatographic analysis revealed a 1.1:1 mannose/galactose ratio, with a molecular weight between 900,000 and 1,000,000 Da. The calorimetric analysis showed a specific vitreous transition temperature of 52.92 °C. The values of apparent viscosity were superior to those of commercial galactomannans, which indicates that MSG can be used too as a thickening agent. The obtained results provide information, which contribute to a better knowledge of MSG, in order to consider its sustainable exploitation in a future.  相似文献   

20.
Residues such as peels and seeds that result from fruit juice production may contain substantial amounts of valuable natural antioxidants. In order to isolate the potential antioxidants gallocatechins and proanthocyanidins, pomace from sea buckthorn (Hippophaë rhamnoides) berries was extracted by acetone-water (75:25, v/v) and fractionated by Sephadex LH-20 gel chromatography and semipreparative HPLC. The structures of the monomeric flavan-3-ols isolated, (+)-gallocatechin and (–)-epigallocatechin, were elucidated by electrospray mass spectrometry (ESI-MS) and 1H and 13C NMR spectroscopy. Five dimeric proanthocyanidins were identified by HPLC-ESI-MS(-MS) and by acid-catalyzed cleavage in the presence of phloroglucinol. Moreover, nine trimeric proanthocyanidins were tentatively identified by HPLC-ESI-MS(-MS) in the Sephadex fractions of sea buckthorn pomace. The isolated flavan-3-ols and proanthocyanidins were potent in scavenging Fremys salt, a synthetic free radical. They possessed antioxidant capacities that were higher or comparable to that of ascorbic acid or Trolox. On comparing the antioxidant capacities of monomeric flavan-3-ols and dimeric proanthocyanidins, no significant influence from the degree of polymerization (DP) was observed.  相似文献   

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