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正乌金木学名赛鞋木豆,天然的木色和跳动的纹理极具流动感,使得用乌金木打造的家具呈现跃进的层次和流线美。在欧洲很多流传至今的家具都是用乌金木打造的,历经百年岁月越发温润如玉,可谓木中贵族,其中尤以非洲乌金木品质为佳。现代家居中,用乌金木制作的家具也并不少见,所 相似文献
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对柞木木材自身弦/径面强度及其水性高分子异氰酸酯(API)胶粘剂胶合试件弦/径面胶接强度进行了研究。结果表明:柞木木材API胶粘剂弦/径面胶合试件常态压缩剪切强度存在着差异;柞木径切面API胶合试件的常态压缩剪切强度比弦切面胶合试件的常态压缩剪切强度高;径切面API胶合试件的常态压缩剪切强度是弦切面的1.22倍;而柞木弦、径面API胶合试件的反复煮沸压缩剪切强度没有显著性的差别。柞木木材本身弦/径面顺纹抗剪强度试验结果表明:柞木木材径向的顺纹抗剪强度为14.41MPa,柞木木材弦向的顺纹抗剪强度为14.97MPa,尽管弦径向间差别不大,但经t-检验证明:柞木的弦/径向间顺纹抗剪强度有显著性的差别,柞木的径向顺纹抗剪强度比弦向顺纹抗剪强度小。 相似文献
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初步研究了杉木、杨树、巨桉、尾巨桉、柠檬桉和窿缘桉等六种人工林木材的胶合性能,结果表明:胶合剪切强度沿杉木、杨树、巨桉、尾巨桉、柠檬桉和窿缘桉顺序增大;六种木材胶合性能差异显著,其中杉木、杨树、巨桉和尾巨桉胶合性能较好,表现为胶合剪切强度能达到标准要求、且木破率高;柠檬桉和窿缘桉木破率低,难于胶合,胶合性能有待改进;胶粘剂类型影响木材胶合性能,其中API和PF剪切强度和木破率平均值高于PVAc和UF;热压胶合的PF和UF的离散性比冷压胶合的API和PVAc要差。 相似文献
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P. Wyler L. H. P. Angeloni A. R. Alcarde S. H. da Cruz 《Journal of the Institute of Brewing》2015,121(1):62-69
Maturation in wood is an important practice that is widely used in the production of high‐quality beverages. The effect of French oak cubes on young lager beer was studied. Oak cubes (with light, medium or heavy toasting) were added to the beer, which was stored at 0°C for 3 months. Beer samples were analysed monthly, and an acceptance test was performed at the end of 3 months. The content of volatile compounds (aldehydes, esters and higher alcohols) was determined by gas chromatography using a flame ionization detector, and the content of low molecular weight phenolic compounds was determined by high‐performance liquid chromatography. The contents of aldehydes, esters, higher alcohols and wood‐derived compounds increased during the 3‐month maturation period. Lager beer stored with heavily toasted oak cubes had the highest concentration of low‐molecular‐weight phenolic compounds, followed by the beer matured in an oak barrel. These results suggest that beer maturation in wood barrels or with oak cubes changed the composition of their oak‐related aromatic compounds, indicating that interactions between the beer and the wood occurred. Copyright © 2015 The Institute of Brewing & Distilling 相似文献
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Brígida Fernández de Simón Teresa Hernández Estrella Cadahía Montserrat Dueñas Isabel Estrella 《European Food Research and Technology》2003,216(2):150-156
A red Rioja wine was aged in barrels made of Spanish oak wood for 21 months. The evolutions of colour percentage intensity, families of phenolic compounds and low molecular weight phenolic compounds were studied in these wines and compared with those of the same wine aged in barrels made of French and American oak. The analysis of chromatic parameters and total anthocyanins indicates that the wines aged in Spanish and French oak wood barrels have similar chromatic characteristics, but are significantly different to those of wines aged in barrels made of American oak wood, indicating a different degree of modification of the colour. The ageing process also had an important influence on the low molecular weight polyphenols composition of wine. The evolution of these components allowed the production of wines with different characteristics, in relation to the type of wood used in barrel making process. On the other hand, Spanish oak wood can be considered suitable for barrel production for quality wines, since a wine aged in barrels made of Spanish oak wood showed similar and intermediate characteristics to those of the same wine aged in French and American oak woods. 相似文献
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A.M. JORDÃO J.M. RICARDO‐DA‐SILVA O. LAUREANO W. MULLEN A. CROZIER 《Australian Journal of Grape and Wine Research》2008,14(3):260-270
Background and Aims: During ageing in oak barrels, wine undergoes changes because of the release of polyphenols and other molecules from wood. The aim of this study was to evaluate the influence of some oak wood‐derived volatile compounds, ellagic acid and oak wood extracts on the levels of (+)‐catechin, procyanidin B1 and malvidin‐3‐glucoside. Methods and Results: Phenolics and the oak wood derived volatile compounds studied were quantified by HPLC and by GC, respectively. Additionally, the new compounds formed in the solutions were characterised by their spectral properties. Ellagic acid and/or oak wood extracts slowed the decline in the levels of (+)‐catechin and procyanidin B1. In contrast, the decrease in malvidin‐3‐glucoside was more pronounced in the presence of ellagic acid and oak wood chip extracts. Furfural slowed (+)‐catechin degradation, while breakdown of malvidin‐3‐glucoside was slightly more pronounced in the presence of guaiacol, furfural, vanillin and eugenol. (+)‐Catechin, procyanidin B1 and malvidin‐3‐glucoside did not significantly affect the rate of the degradation of ellagitannins during the storage time studied. Finally, new HPLC peaks were detected in the solutions containing (+)‐catechin and ellagic acid, as well as with malvidin‐3‐glucoside with ellagic acid and oak wood extract. Conclusions: Malvidin 3‐glucoside and (+)‐catechin and procyanidin B1 presented distinct behaviours during time in the presence of volatile and non‐volatile compounds from oak wood. Significance of the Study: This work points out the importance of oak wood components in the degradation of anthocyanins and tannins, as well as the reactions that occur during the ageing of red wine. 相似文献
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M. S. Pérez-Coello M. A. González-Viñas E. García-Romero M. D. Cabezudo & J. Sanz 《International Journal of Food Science & Technology》2000,35(1):23-32
Summary Three samples of French oak and one sample of American oak were analyzed by different gas chromatographic-mass spectrometric (GC/MS) methods. Two methods of quantifying the main volatile compounds in oak wood were compared, namely, Direct Thermal Desorption coupled with GC/MS and analysis of mixtures of water-ethanol and wines that had been in contact with oak chips by extraction using an organic solvent followed by GC/MS analysis of the extract. The ratio of the two oak lactones released into the wine by the oak chips was the same as the ratio observed in original, untreated wood. These substances are of particular sensory importance in wines aged in oak wood barrels. Thus, the use of oak chips in white wines may be advantageous. The wines steeped with the oak chips improved their acceptability rating 2 points on a scale of 9. 相似文献
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António M. Jord?o Ana C. Correia R. DelCampo Maria L. González SanJosé 《European Food Research and Technology》2012,235(5):817-825
In 2005, the European Union authorized the use of oak wood pieces in winemaking, and consequently, the addition of oak chips has been generalized. Thus, the antioxidant capacity, scavenger activity, and ellagitannins content from fourteen different commercial oak wood pieces (Quercus spp.) that can be found on the Portuguese market as alternatives to barrels for aging wines were studied. Commercial oak wood pieces samples from Quercus petraea had significantly higher antioxidant activity values than the pieces from Quercus alba species. In general, antioxidant capacity and scavenging activity decrease with the toasting level of the oak wood pieces samples analyzed. A similar effect was detected in the individual ellagitannin content studied. On the other hand, with the toasting process, the total phenolic content and the ellagic acid concentration increased. Finally, a correlation analysis revealed that ellagitannins contribute to the antioxidant capacity of oak wood pieces studied. From the data presented in this paper, antioxidant capacity and ellagitannin content of the oak wood pieces studied have been clearly related either to the oak wood species used, particle size, or to toasting levels. 相似文献
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Investigations have shown that regarding ovendry density, hygroscopicity and volumetric swelling the stump wood of spruce, beech and oak does not differ significantly from the respective stem wood. In comparison to stump wood the ovendry density of root wood of spruce was slightly higher, that of beech and oak distinctly lower. The equilibrium moisture content of these three root woods in comparison proved to be clearly higher only in the range of very high relative humidity. The volumetric swelling of root wood at 100% relative humidity was for spruce appr. 1.25 times, for beech 1.6 times and for oak 2.0 times as high as that of stump wood. This was caused by the fact that in contrast to stump woods, swelling of the three root woods caused an expansion of their pore volume (“irregular volumetric swelling”). 相似文献
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The antioxidant capacity of oak wood used in the ageing of wine was studied by four different methods: measurement of scavenging capacity against a given radical (ABTS, DPPH), oxygen radical absorbance capacity (ORAC) and the ferric reducing antioxidant power (FRAP). Although the four methods tested gave comparable results for the antioxidant capacity measured in oak wood extracts, the ORAC method gave results with some differences compared to the other methods. Non-toasted oak wood samples displayed more antioxidant power than toasted ones due to differences in the polyphenol composition. A correlation analysis revealed that ellagitannins were the compounds mainly responsible for the antioxidant capacity of oak wood. Some phenolic acids, mainly gallic acid, also showed a significant correlation with antioxidant capacity. 相似文献
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Knowledge on wood natural durability is required in order to be able to decide if we can use a certain type of wood outdoors. For instance, when used outside, oak wood is subjected to the leaching of its water-soluble substances. In this case the resistance of European oak wood is considered to be durable according to the European Standard EN 350-2. However, so far we do not exactly know the real impact of the leaching phenomenon on the resistance of oak wood and the importance of chemical contents. Nevertheless, our study has indicated that some individuals may contain highly durable wood characteristics even after the leaching process (i.e. 33% of very durable wood was still very durable after the leaching test). Chemical analysis has demonstrated that the presence of phenolic compounds are positively correlated with durability. This means that higher proportions of phenol confer higher resistance on wood. After the leaching test, which involves a washout of water soluble compounds, 70% of the trees demonstrate a decline in durability (after the leaching test 75% of the very durable wood dropped to a durable class; whereas, 25% of the wood in the same class still kept their very durable status). This experiment clearly shows the influence of the leaching phenomena and its important role on durability in oak wood. The results show also that 18% of the oak samples could be considered as very durable even after leaching. 相似文献
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Hydrolysis of glycosidically bound flavour compounds from oak wood by Oenococcus oeni 总被引:1,自引:0,他引:1
Malolactic fermentation (MLF), which is conducted by lactic acid bacteria (LAB), has a significant influence on the stability and organoleptic quality of wine. Recent studies have shown that when MLF is carried out in oak wood barrels, LAB were also able to interact with wood and increase volatile compound contents such as vanillin during MLF. The release of these compounds indicates that LAB may convert vanillin precursors present in oak wood. In this work, the effect of commercial glycosidases on the released vanillin was firstly studied. This aldehyde is present in wood extracts in monoglycosidic forms where the major glycones are arabinose and xylose. Other aglycons released during MLF in barrels, syringaldehyde and whisky-lactones, can be considered as other sources of aroma. Secondly, strains selected with high activities toward glycoside substrates could hydrolyse vanillin glycoside precursors from oak wood with the same efficiency as commercial enzymes. 相似文献
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Monosaccharide anhydrides,new markers of toasted oak wood used for ageing wines and distillates 总被引:1,自引:0,他引:1
In order to shed light on the thermal carbohydrate transformation chemistry, the non-volatile composition of natural and toasted oak wood samples of different origins were studied. GC–MS analysis revealed the presence of monosaccharide anhydrides (MAs) only in toasted oak wood samples. They were formed by the cellulose and hemicelluloses thermal degradation produced during the toasting process, and the content was dependent on the degree of toasting. The principal MAs formed in the oak wood toasting process were 1,6-anhydro-β-d-glucopyranose (levoglucosan), 1,6-anhydro-β-d-galactosane (galactosan) and 1,6-anhydro-β-d-mannopyranose (mannosan), with levoglucosan being the dominant MAs detected. Monosaccharide anhydrides can be considered specific products formed during the thermal treatment of wood; therefore they are proposed as markers of toasted wood and could be used to monitor and determine the intensity of toasting process. 相似文献