School of Life Science and Biotechnology, Korea Univ, 5-1, Anam-dong, Sungbuk-gu, Seoul 136-701, Republic of Korea.
J Food Sci. 2014 Jun;79(6):C1106-16. doi: 10.1111/1750-3841.12489. Epub 2014 May 29.
In Korean rice wine (makgeolli) model, we tried to develop a prediction model capable of eliciting a quantitative relationship between initial amino acids in makgeolli mash and major aromatic compounds, such as fusel alcohols, their acetate esters, and ethyl esters of fatty acids, in makgeolli brewed. Mass-spectrometry-based electronic nose (MS-EN) was used to qualitatively discriminate between makgeollis made from makgeolli mashes with different amino acid compositions. Following this measurement, headspace solid-phase microextraction coupled to gas chromatography-mass spectrometry (GC-MS) combined with partial least-squares regression (PLSR) method was employed to quantitatively correlate amino acid composition of makgeolli mash with major aromatic compounds evolved during makgeolli fermentation. In qualitative prediction with MS-EN analysis, the makgeollis were well discriminated according to the volatile compounds derived from amino acids of makgeolli mash. Twenty-seven ion fragments with mass-to-charge ratio (m/z) of 55 to 98 amu were responsible for the discrimination. In GC-MS combined with PLSR method, a quantitative approach between the initial amino acids of makgeolli mash and the fusel compounds of makgeolli demonstrated that coefficient of determination (R(2)) of most of the fusel compounds ranged from 0.77 to 0.94 in good correlation, except for 2-phenylethanol (R(2) = 0.21), whereas R(2) for ethyl esters of MCFAs including ethyl caproate, ethyl caprylate, and ethyl caprate was 0.17 to 0.40 in poor correlation.
The amino acids have been known to affect the aroma in alcoholic beverages. In this study, we demonstrated that an electronic nose qualitatively differentiated Korean rice wines (makgeollis) by their volatile compounds evolved from amino acids with rapidity and reproducibility and successively, a quantitative correlation with acceptable R2 between amino acids and fusel compounds could be established via HS-SPME GC-MS combined with partial least-squares regression. Our approach for predicting the quantities of volatile compounds in the finished product from initial condition of fermentation will give an insight to food researchers to modify and optimize the qualities of the corresponding products.
在韩国米酒（makgeolli）模型中，我们试图开发一种能够定量描述米酒醪初始氨基酸与主要芳香化合物（如杂醇醇、它们的乙酸酯和脂肪酸乙酯）之间关系的预测模型。基于质谱的电子鼻（MS-EN）用于定性区分由不同氨基酸组成的米酒醪制成的米酒。在此测量之后，采用顶空固相微萃取结合气相色谱-质谱联用（GC-MS）与偏最小二乘回归（PLSR）方法定量关联米酒醪的氨基酸组成与米酒发酵过程中产生的主要芳香化合物。在 MS-EN 分析的定性预测中，根据米酒醪氨基酸衍生的挥发性化合物，makgeollis 得到了很好的区分。27 个质量电荷比（m/z）为 55 至 98amu 的离子碎片负责区分。在 GC-MS 结合 PLSR 方法中，米酒醪初始氨基酸与米酒杂醇化合物之间的定量关系表明，大多数杂醇化合物的决定系数（R²）在 0.77 到 0.94 之间具有良好的相关性，除了 2-苯乙醇（R²=0.21），而包括乙酯辛酸乙酯、乙酯辛酸乙酯和乙酯辛酸乙酯在内的 MCFAs 乙酯的 R²为 0.17 到 0.40 相关性较差。
氨基酸已被证明会影响酒精饮料的香气。在这项研究中，我们证明电子鼻能够快速、重现地通过氨基酸衍生的挥发性化合物定性区分韩国米酒（makgeollis），并且通过 HS-SPME GC-MS 结合偏最小二乘回归，可以成功建立氨基酸和杂醇化合物之间具有可接受的 R²的定量相关性。我们从发酵初始条件预测成品中挥发性化合物数量的方法将使食品研究人员能够修改和优化相应产品的质量。
