Background : The interest in paddy-converted fields to be used as an alternative new farming area for the stable ginseng production is increasing, and made up -32% of the total ginseng cultivation area in Korea in 2014. Therefore, this study examined how soil types and fertilizer regimes influence fatty acid (FA) and vitamin E (Vit-E) variation in 6-years-old ginseng root.
Methods and Results : Ginseng variety “Jagyeongjong” was cultivated upland and paddy-converted field, and three organic fertilizers were applied to both fields, at 0, 1, 2, and 4 tons per 1,000 ㎡, prior to the ginseng seedling transplantation. The 37 FAs and 8 Vit-E were analyzed with GC-FID. We observed significant variation in both FA and Vit-E contents owing to the type and quantity of organic fertilizer used in each soil type during cultivation. Unsaturated FAs were approximately 2.7-fold higher in ginseng than in saturated FAs. Linoleic, palmitic, and oleic acids were the most abundant FAs detected in ginseng roots. Additionally, α-tocopherol was the major Vit-E detected. In particular, the increased application of rice straw compost or food waste fertilizer elevated the quantity of nutritionally desirable FAs and bioactive Vit-E in ginseng root. Partial least square-discriminant analysis (PLS-DA) score plots showed that soil type might be the main cause of differences in FA and Vit-E levels in ginseng. Specifically, the PLS-DA model indicated that palmitic acid is a suitable FA marker in determining whether ginseng plants were grown in a paddy-converted field or an upland field. Moreover, linoleic acid levels were highly correlated with α-linolenic acid (r = 0.8374) according to Pearson's correlations and hierarchical clustering analysis.
Conclusion : This study investigated how soil type, as well as organic fertilizer type and amount, altered the FA and Vit-E profiles in ginseng roots. Therefore, these preliminary data should be beneficial to ginseng farmers and any industries involved in the production of high quality and nutritional ginseng products.