This study revealed the compositional characteristics of sunki, a traditional, unsalted, lactic acid-fermented pickle produced using turnip leaf in Kiso district, Japan. Comprehensive compositional analysis by two metabolomic approaches based on NMR and solid-phase microextraction-GC/MS methods was used to determine its chemical composition by annotating 54 water-soluble and 62 volatile compounds. Principal component analysis showed that samples had different compositions, depending on the agricultural processing factory and production year. This variation potentially resulted from the differences in the lactic acid bacterial community produced during the spontaneous fermentation of sunki and in the initial nutritional composition of the turnip leaf. Partial least squares regression revealed that the acetic acid level showed a strong positive correlation with pH (R = 0.810), in contrast to the negative correlations of lactic acid and ethanol levels (R = −0.533 and −0.547). This indicated the crucial impact of acetic acid-related metabolism on acidification during sunki fermentation.

这项研究揭示了奇奇的组成特征，奇奇是一种使用日本芜菁叶在日本木曾区生产的传统，无盐，乳酸发酵的咸菜。通过两种基于NMR的代谢组学方法和固相微萃取-GC / MS方法对成分进行了全面的成分分析，通过注释54种水溶性和62种挥发性化合物来确定其化学成分。主成分分析表明，根据农业加工厂和生产年份的不同，样品的成分也不同。这种变化可能是由于sunki自发发酵过程中产生的乳酸菌群落的差异所致。以及萝卜叶的初始营养成分。偏最小二乘回归显示，乙酸水平与pH呈强正相关（R  = 0.810），而乳酸和乙醇水平则呈负相关（R  = -0.533和-0.547）。这表明在桑基发酵过程中，乙酸相关代谢对酸化的关键影响。