Targeted at the aged Fengxiang crude Baijiu stored in Jiuhai, a container for Chinese Baijiu, this paper adopted the gas chromatography-mass spectrometry (GC-MS) and gas chromatography-ion mobility spectrometry (GC-IMS) to analyze the changes of volatile substances in the Fengxiang Baijiu. The results indicated that 85 compounds were detected by GC-MS, including 41 esters, 10 acids, 17 alcohols, and some compounds with high molecular weight. During storage, the content of esters decreased obviously, that of acids increased, and that of higher fatty acid esters such as ethyl palmitate, ethyl linoleate, elaidic acid ethyl ester, and stearic acid ethyl ester, and phenylethyl alcohol showed a linear growth. In contrast, a total of 47 compounds, dominated by 23 esters and 14 aldehydes and ketones, were identified by GC-IMS, as it was more sensitive to substances with small molecules. It was found that the content of dipropyl sulfide, isopentane, diacetyl, etc., increased with time. The principal component analysis (PCA) of the two techniques showed that there were significant differences between aged crude Baijiu. Combining the above two techniques, a change law of the volatile components in aged Fengxiang crude Baijiu was derived, the content of acids increased, that of esters declined, and that of ethyl palmitate, ethyl linoleate, elaidic acid ethyl ester, stearic acid ethyl ester, phenylethyl alcohol, benzaldehyde, dimethyl sulfide, and lactic acid grew. It was expected that the results of this paper could provide a theoretical basis for the establishment of the aging system of Fengxiang Baijiu.

为研究贮酒容器对凤香型白酒香气成分的影响,采用电子鼻与气相色谱离子迁移谱(gas chromatography-ion mobility spectrometry,GC-IMS)技术对不同容器贮存的凤香型白酒风味物质及理化指标——乙醇体积分数、总酸、总酯、可溶性固形物质量浓度及pH值进行分析和比较,以期为凤香型白酒贮存工艺的改进提供参考.电子鼻和GC-IMS分析结果均表明:新产酒与贮酒香气特征有显著差别,陶坛与不锈钢罐贮酒风格相似,而酒海贮酒风格独特.GC-IMS在4类酒样中共检测出66种挥发性成分,主要为酯类、醛类、酮类、醇类物质;不锈钢罐和陶坛贮酒中乙醇酯类、双乙酰、1-丙醇等物质相对含量较高,在酒海贮酒中含有较多的高级醇酯类、醛酮类等物质;酒海贮酒中具有最低总酸质量浓度,最高可溶性固形物质量浓度、乙醇体积分数和最高的pH值.

为探索贮酒容器对凤香型白酒风味物质的影响,采用气相色谱法、顶空固相微萃取及气相色谱-质谱联用法和超高效液相色谱法,以新酒为对照,对酒海贮酒、陶坛贮酒、不锈钢罐贮酒及对照4种酒样的风味物质进行分析.结果鉴定出酯类、醇类、酸类、醛酮类和酚类5类组分;其中,新酒的风味物质种类最少,其总质量浓度最高(79种、7 756mg/L),酒海贮酒的风味物质种类较多,但其质量浓度最低(94种、4 276mg/L),而陶坛和不锈钢罐贮酒种类最多,均为96种;其总质量浓度低于新酒而高于酒海贮酒(分别为5 957 mg/L和5 360 mg/L).主成分分析及热图分析结果表明,不锈钢罐和陶坛贮酒在异戊醇、异丁醇、月桂酸乙酯、己酸-2-苯乙酯、己酸糠酯和乙缩醛等物质上具有较高的相关性,呈花香和果香的特征;酒海贮酒在十八酸乙酯、亚麻酸乙酯、苯乙醇和苯甲醛等物质上具有较高相关性,呈果香、甜香、蜜香和杏仁香特征.贮酒容器对贮酒中风味物质的影响可能与贮酒容器的透气性、释放过渡金属离子的性能以及对贮酒pH值的影响有关.

借助衍生化方法和气相色谱-质谱联用仪检测,并结合代谢组学的分析方法,对不同年份基酒中差异化合物进行研究.结果表明:不同年份基酒共鉴定出59种化合物,包括30种有机酸、10种氨基酸、7种糖类物质、7种糖醇类物质和5种其他化合物.样本树状图、PCA和PLS-DA分析发现新酒和贮存2年的酒归为一类,贮存3年和5年的酒归为一类,贮存7年和9年的酒归为一类,不同年份基酒之间分类明显,表明不同年份基酒之间在化合物种类和含量上存在明显差别.通过VIP变量重要性筛选出20种差异化合物,包括有机酸、氨基酸、糖类、甘油等,这些物质在贮存过程中含量明显升高,这与酒海制作过程中内壁材料的特殊性有关,这也是新酒经过酒海贮存一段时间后酒体变得更加醇厚的原因,酒海贮存对于酒体风味的形成具有重要作用.