‘美乐’和‘威代尔’冰酒在贮藏过程中理化性质和挥发性风味物质的动态变化

Dynamic Changes in the Physicochemical Properties and the Volatile Flavor Compounds in ‘Merlot’ and ‘Vidal’ Icewines during Storage

对新疆维吾尔自治区伊犁地区生产的‘美乐’和‘威代尔’冰酒在贮藏过程(以0、1 a和2 a代表乙醇发酵结束、贮藏1 a和2 a)中的变化进行监测。为了探讨贮藏期对冰酒质量的影响,采用高效液相色谱法、滴定法、分光光度法和顶空固相微萃取结合气相色谱-质谱联用技术对冰酒的理化性质和香气化合物进行了检测。根据SPSS统计分析结果,依据品种对冰酒的理化指标得到了较好地区分。贮藏2 a后,‘美乐’冰酒中总酸、挥发酸和苹果酸含量分别下降5.9%、13.2%和39%,乳酸含量增加57.2%。贮藏1 a后,褐变指数、酒色、色度、色价、黄色占比和红色占比的含量均有显著变化,色度、色价和黄色占比的含量随贮藏时间的增加呈上升趋势,但红色占比呈下降趋势。贮藏2 a后,‘威代尔’冰酒中的总酸和苹果酸分别增长9.8%和33.1%,而挥发酸下降29.8%。贮藏1 a后‘威代尔’冰酒的酒色、褐变指数、色度、色价和黄色占比的含量显著变化,酒色和色度含量随贮藏时间的延长而增加,但红色占比和蓝色占比与之前相比无差异。根据主成分分析结果,各种冰酒不同贮藏时间后挥发性物质有显著变化,2种冰酒中的挥发性物质得到明显区分。2款冰酒产生最多新物质的时期均是贮藏2 a后。其中,‘美乐’冰酒中出现异丙醇、乙酸异戊酯、己酸乙酯、乙酸己酯、癸醛、香茅醇、苯乙酸乙酯、乙酸苯乙酯、β-大马士酮,而在威代尔冰酒中发现:1-戊醇、异戊醇、甲酸乙酯、异丙醇、糠醛、1-丁醇、乙酸异戊酯、3-羟基丁醛、乙酸己酯、乙酸辛酯、3,4-二甲基苯甲醛、5-羟甲基糠醛、乙酸苯乙酯、β-大马士酮。结果表明,贮藏时间对冰酒的理化性质和香气化合物的变化起着关键作用。本实验发现‘威代尔’冰酒的成分在贮存过程中比‘美乐’冰酒的成分更易变。

In our study, the quality changes of ‘Merlot’ and ‘Vidal’ icewines produced in Yili, Xinjiang Uygur Autonomous Region were monitored during two-year storage at intervals of one year. The physicochemical properties and aroma compounds of icewines were determined by high performance liquid chromatography(HPLC), titration, spectrophotometry and headspace solid phase microextraction combined gas chromatography(HS-SPME-GC-MS). According to the results of SPSS statistical analysis, good discrimination was achieved among icewines based on the physicochemical indexes. After two-year storage, the contents of total acid, volatile acids and malic acids in ‘Merlot’ icewine decreased by 5.9%, 13.2% and 39%, respectively, and lactate content increased by 57.2%. Browning index(BI), wine color(WC), color intensity(CI), color hue(CH), and the proportions of yellow(Ye) and red(Rd) changed significantly after one year of storage;CI, CH and Ye showed increasing trends with storage time, while Rd showed an opposite trend. After two-year storage, the contents of total acid and malic acid in ‘Vidal’ icewine increased by 9.8% and 33.1%, respectively, while the content of volatile acid decreased by 29.8%. WC, BI, CI, CH, and Ye changed significantly after one year of storage;WC and CI increased with storage time, whereas there was no significant difference in Rd or the proportion of blue(Bl). The results of principal component analysis(PCA) showed clear discrimination among icewine samples of different ages and between the two icewines. Two-year-old icewines contained the largest number of volatile compounds such as isopropyl alcohol, isoamyl acetate, ethyl hexanoate, hexyl acetate, decanal, citronellol, ethyl phenylacetate, phenethyl acetate, and β-damascenone in ‘Merlot’ icewine;and 1-pentanol, isoamyl alcohol, ethyl formate, isopropyl alcohol, furfural, 1-butanol, isoamyl acetate, acetaldol, hexyl acetate, octyl acetate, 3,4-dimethylbenzaldehyde, 5-hydroxymethylfurfural, phenethyl acetate, β-damascenone in ‘Vidal’ icewine. The above results showed that storage time had a significant impact the physicochemical properties and aroma compounds of icewines. Most importantly, we found that the volatile flavor composition of ‘Vidal’ icewine changed more significantly as compared to ‘Merlot’ icewine during storage.