The effects of exogenous sodium nitroprusside (SNP, nitric oxide donor) on the growth, yield, photosynthetic characteristics, and antioxidant enzyme activity of kimchi cabbage (Brassica rapa L. subsp. pekinensis (Lour.) Hanelt) was studied under the low temperature conditions. Kimchi cabbages were treated with SNP of three concentrations (7.5, 15, 30 mg·L-1) for three times at four-day intervals and exposed to low temperature (16/7°C) stress for seven days. SNP treatment induced increases of net photosynthetic rate (Pn), stomatal conductance (Gs), intracellular CO2 concentration (Ci) and transpiration rate (Tr) under the stress condition with the highest level after the third treatment. The contents of malondialdehyde (MDA) and H2O2 were significantly lower in the treatment of SNP compared to the non-treated control. The activity of ascorbate peroxidase (APX), catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD), increased in treated plants by up to 38, 187, 24 and 175%, respectively compared to the non-treated control. SNP-treated and untreated plants had similar growth characteristics. Compared to the control group, SNP-treatment increased fresh weight and leaf area by 5%. Overall, our findings suggest that the application of sodium nitroprusside to the leaves contributes to reducing physiological damage and enhancing the activities of antioxidant enzymes, thereby improving low temperature stress tolerance in kimchi cabbage.

In Western countries, kimchi, the Korean traditional fermented cabbage, is considered to be a healthy. However, it is one of the main sources of the high sodium content of the Korean diet. In order to decrease the sodium content, we manufactured a low-sodium kimchi (LK, salinity 1.0%) and 4 additional low-sodium kimchi starters in which each of 4 lactic acid bacteria (Lb. sakei 1, Lb. sakei 2, Lb. palntarum and W. koreensis) were added. The LKL1 to LKL4 samples were prepared by adding 4 single LAB starters, each with an inoculum size of 106 CFU/g, when the cabbage was mixed with kimchi sauce. The kimchi starters were fermented at 10℃ until reaching 0.5% acidity, and then stored at －1.5℃ until reaching 0.75% acidity. The pH and acidity of the starter kimchi changed more rapidly in the early phase of fermentation (up to 0.75% acidity) than control low-sodium kimchi. After the acidity of the kimchi starters reached 0.75% it remained constant. As the fermentation progressed, the total aerobic and lactic acid bacteria concentrations in the kimchi starter with added Lb. sakei 1 were the same as in the control low-sodium kimchi. The low-sodium kimchi fermentation of the kimchi starter with added Lb. palntarum progressed differently due to a difference in acid resistance. The kimchi starter with added Lb. sakei 2 had an overall liking score that was slightly higher than that of the control low-sodium kimchi due to a lower off-flavor

This study investigated the fermentative characteristics and immunomodulating activity in Kimchi added with various salts(salt replacement and herb-salt with Acanthopanax senticosus and Glycyrrhizae uralensis) for the reduction of Na concentration in Kimchi. Kimchi using a salt replacement and herb-salt showed a higher level of acidity (0.8～0.84%) than that of the control (0.7%) at 7-day fermentation. Kimchi using a salt replacement and herb-salt showed a lower level of salinity (1.72～1.98%) than that of control (2.3～2.57%) during fermentation. The growth of Lactobacillus spp. and Leuconostoc spp. recorded the highest level (2.3×10⁸ and 2.8×10⁶ cfu/g, respectively) in control at 6 day fermentation. However, those levels in Kimchi prepared with salt replacement and herb-salt were 3.5～5.4×10⁸ and 6.1×10⁶ cfu/g, respectively. It is assumed that the high level of acidity of Kimchi prepared with salt replacement and herb-salt was caused by the increase in the growth of Lactobacillus spp. and Leuconostoc spp.. When the macrophage stimulating activity of salt replacement kimchi (Salt-R kimchi) supplemented with hot-water extract from Acanthopanax sentisus (AS) or Glycyrrhiza uralensis (GU) was investigated on aging period, Salt-RA kimchi with AS 5% at 6 days (2.78-fold of saline control at 100 ㎍/㎖) and Salt-RG kimchi with GU 5% at 9 days (2.02-fold) significantly increased compared to the Salt-RA kimchi without AS or GU. In addition, Salt-RAG kimchi with AS 3% and GU 3% improved the bitter taste of Salt-RA and potently stimulated the macrophage at 6 days (1.28-fold of Salt-R kimchi) even though its activity was lower than Salt-RA (5%, 1.39-fold).