PDF(Pubmed)
Abstract：
Fermentation-a process of compound degradation by microorganisms-is a traditional food processing method utilized worldwide for the long-term preservation of fresh foods. In recent years, fermented foods have gained attention as health foods. Fermentation increases the nutritional value of ingredients, producing complex flavors and aromas. To identify unknown components in fermented foods, it is necessary to analyze compounds and conditions nondestructively and comprehensively. We performed intact-state nuclear magnetic resonance (NMR) spectroscopy using intermolecular single quantum coherence (iSQC) to detect the degradation of vegetables directly and nondestructively. We used two types of vegetables and a rice bran bed (nukazuke), which is used for traditional vegetable fermentation in Japan. Major metabolites such as saccharides, organic acids, and amino acids were identified in iSQC-sliced spectra. Comparing NMR signal intensities during degradation revealed the transition of metabolites characteristic of lactic acid fermentation. A pathway-based network analysis showed pathways involved in amino acid metabolism and lactic acid fermentation. Our analytical approach with intact-state NMR spectroscopy using iSQC demonstrated that it may be effective in other experimental systems, allowing for the evaluation of phenomena that have been conventionally overlooked in their true state.
摘要：
发酵-微生物降解化合物的过程-是世界范围内用于长期保存新鲜食品的传统食品加工方法。近年来,发酵食品作为保健食品受到关注。发酵增加了配料的营养价值，产生复杂的味道和香气。为了识别发酵食品中的未知成分，有必要对化合物和条件进行无损全面的分析。我们使用分子间单量子相干（iSQC）进行了完整状态的核磁共振（NMR）光谱，以直接和非破坏性地检测蔬菜的降解。我们使用了两种蔬菜和米糠床（nukazuke），用于日本传统的蔬菜发酵。主要代谢物，如糖类，有机酸,在iSQC切片光谱中鉴定了氨基酸。比较降解过程中的NMR信号强度揭示了乳酸发酵的代谢物特征的转变。基于途径的网络分析显示了涉及氨基酸代谢和乳酸发酵的途径。我们使用iSQC进行完整状态NMR光谱的分析方法表明，它可能在其他实验系统中有效，允许评估在真实状态下通常被忽视的现象。
