Kimchi cabbage (Brassica rapa subsp. pekinensis [Lour.]) Metabolic changes during growing seasons in the Republic of Korea

Kimchi cabbage is a cool-season plant, but it is grown year-round to meet the high demand for kimchi production. Understanding the plant's seasonal characteristics is crucial for ensuring consistent quality. However, kimchi cabbages are grown in diverse locations with varied growing conditions and soil types, which creates an obstacle for producing uniform kimchi. To address this issue, we conducted research on sensorial-related metabolites and glucosinolates to characterize kimchi cabbages from four seasons in the Republic of Korea. Our findings revealed that fall and winter-grown kimchi cabbages had higher levels of compatible solutes (proline and sucrose) compared to those from spring and summer. These differences are likely due to low temperatures after the heading stage and freezing soil that induces drought stress. Additionally, extensive pest damage in the spring and summer increased the bitterness of kimchi cabbage, which may be attributed to neoglucobrassicin. These kimchi cabbage characteristics were confirmed with five cultivars grown in Naju, Jeollanam Province, for the spring and fall seasons. Our study suggests that kimchi cabbages grown in spring and summer have similar metabolite levels and increasing temperature regimes, a trend also found in fall/winter-grown kimchi cabbages. This study is the first attempt to characterize kimchi cabbage attributes grown during four different seasons.