Department of Food and Bioproduct Sciences, Saskatoon, Saskatchewan S7N 5A8 Canada.
J Agric Food Chem. 2011 Oct 12;59(19):10454-60. doi: 10.1021/jf2026007. Epub 2011 Sep 15.
Thin stillage contains organic and inorganic compounds, some of which may be valuable fermentation coproducts. This study describes a thorough analysis of the major solutes present in thin stillage as revealed by NMR and HPLC. The concentration of charged and neutral organic compounds in thin stillage was determined by excitation sculpting NMR methods (double pulse field gradient spin echo). Compounds identified by NMR included isopropanol, ethanol, lactic acid, 1,3-propanediol, acetic acid, succinic acid, glycerophosphorylcholine, betaine, glycerol, and 2-phenylethanol. The concentrations of lactic and acetic acid determined with NMR were comparable to those determined using HPLC. HPLC and NMR were complementary, as more compounds were identified using both methods. NMR analysis revealed that stillage contained the nitrogenous organic compounds betaine and glycerophosphorylcholine, which contributed as much as 24% of the nitrogen present in the stillage. These compounds were not observed by HPLC analysis.
稀酒糟含有有机和无机化合物，其中一些可能是有价值的发酵副产物。本研究通过 NMR 和 HPLC 对稀酒糟中存在的主要溶质进行了全面分析。通过激发整形 NMR 方法（双脉冲场梯度自旋回波）测定稀酒糟中带电和中性有机化合物的浓度。通过 NMR 鉴定的化合物包括异丙醇、乙醇、乳酸、1,3-丙二醇、乙酸、琥珀酸、甘油磷酸胆碱、甜菜碱、甘油和 2-苯乙醇。用 NMR 测定的乳酸和乙酸浓度与用 HPLC 测定的浓度相当。HPLC 和 NMR 是互补的，因为两种方法都能鉴定出更多的化合物。NMR 分析表明，酒糟中含有含氮有机化合物甜菜碱和甘油磷酸胆碱，它们占酒糟中氮含量的 24%。这些化合物在 HPLC 分析中没有观察到。
