烘烤强度和木纹理对橡木(Quercus petraea)心材多酚和香气的影响

摘要

考察不同烘烤程度对不同纹理橡木心材试样中低分子质量酚酸和挥发性物质含量的影响,结果表明烘烤过程将会改变橡木心材的物质组成,并通过相应的化学反应增加挥发性物质的含量.同时,在不考虑烘烤强度条件下,供试的细纹理橡木心材试样含有较高的挥发性物质含量,例如顺/反橡木内脂、顺/反异丁子香酚、呋喃醛、紫丁香醇,以及芥子醛、松柏醛、香草醛和丁香醛等低分子质量酚类化合物,而中纹理和粗纹理的样品则表现出较高的总酚、总单宁水平,以及较高的鞣花酸和没食子酸含量.此外,主成分分析显示,中纹理和细纹理样品的中度和重度烘烤处理与橡木心材试样的挥发性物质含量有较大的正相关性,而粗纹理的未烘烤和轻度烘烤样品则与试样中总单宁和阿魏酸含量呈正相关.%It is important for winemakers to understand the chemical constituents of oak heartwood used for barrels as different grain types and toasting regimes influence wine flavor.Changes induced by different heating regimes in low-molecular-weight (LMW) phenolics and volatile compounds of oak heartwood of different grain types were evaluated.The results showed that a higher temperature during the toasting process changed the chemical compositions of the heartwood and increased the amounts of several key soluble and volatile compounds as a result of various heat-induced reactions.Moreover,independent of toasting,the fine-grained oak samples had higher concentrations of volatile compounds,e.g.,cisltrans-oak-lactone,cis/trans-isoeugenol,furanic aldehydes,syringol,and LMW phenolics,particularly sinapaldehyde,coniferaldehyde,vanillin,and syringaldehyde,while the medium-and coarse-grained oak samples showed higher levels of total phenol,tannins,ellagic acid and gallic acid.Principal component analysis (PCA) showed that the moderately and heavily toasted samples of medium-and fine-grained oak displayed higher positive correlations with the level of volatile compounds,while the untoasted and lightly toasted heartwood of coarse-grained oak were positively correlated with total tannin and femlic acid contents.