• Journal of Biosystems Engineering
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• v.39 no.3
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• pp.194-204
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• 2014

Purpose: The aim of this study was to develop long-term storage technology for Chinese cabbage in order to extend the period of availability of freshly harvested products. The scope of the paper deals with the use of a cooler with a remote monitoring and control interface in conjunction with use of packaging film. Methods: A cooler with a real time monitoring system was designed as a low-temperature storage facility to control temperature and relative humidity (RH). The effects of storage in high-density polyethylene (HDPE) plastic boxes, 3% chitosan dipping solution, polypropylene film (PEF) with perforations, and mesh packaging bags on physiological responses were investigated. The optimal storage temperature and humidity for 120 days were below $0.5^{\circ}C$ and 90%, respectively. Physiological and biochemical features of cabbage quality were also analyzed: weight loss, texture, and sugar salinity, chlorophyll, reducing sugar, and vitamin C contents. Results: The cooler with a remote monitoring and control interface could be operated by an HMI program. A $0.5^{\circ}C$ temperature and 90% humidity could be remotely controlled within the cooler for 120 days. Postharvest freshness of Chinese cabbages could be maintained up to 120 days depending on the packaging method and operation of the remote monitoring system. In particular, wrapping the cabbages in PEF with perforations resulted in a less than a 5% deterioration in quality. This study provides evidence for efficient performance of plastic films in minimizing post-harvest deterioration and maintaining overall quality of cabbages stored under precise low-temperature conditions with remote monitoring and a control interface. Conclusions: Packaging with a modified plastic film and storage in a precisely controlled cooler with a remote monitoring and control interface could slow down the physiological factors that cause adverse quality changes and thereby increase the shelf life of Chinese cabbage.

• Food Science and Preservation
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• v.22 no.1
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• pp.154-157
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• 2015

To maintain the freshness and to prevent browning of cut Kimchi cabbages, the effect of the cutting process using a ceramic knife under $N_2$ blowing on the quality of the cut Kimchi cabbages was investigated. Kimchi cabbages cut with a ceramic knife under $N_2$ gas blowing conditions (NC) were stored at $5^{\circ}C$ for 7 days, and their weight reduction ratio and the browning degree and appearance were compared with those of the control treatment samples (OS; cut with a stainless steel knife under normal air, OC; cut with a ceramic knife under normal air). The weight reduction ratios were 0.07~0.13%, and the NC treatment showed the lowest reduction ratio among all the treatments (p<0.05). The Hunter L values increased, but the a and b values decreased after 5-day storage in all the treatments. The NC treatment had higher L values but lower a and b values than the OS and OC treatments. The browning degrees by Hunter color value, PPO activity, and appearances were the least in the NC treatment (p<0.05). The cutting process with a ceramic knife under $N_2$ blowing could be applied to the cutting of vegetable products and for minimal fruit processing.

• The Plant Pathology Journal
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• v.35 no.2
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• pp.178-187
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• 2019

Plants are exposed to biotic stresses caused by pathogen attack and complex abiotic stresses including heat and drought by dynamic climate changes. To alleviate these stresses, we investigated two bacterial stains, H26-2 and H30-3 in two cultivars ('Ryeokkwang' and 'Buram-3-ho') of Chinese cabbage in plastic pots in a greenhouse. We evaluated effects of bacterial strains on plant growth-promotion and mitigation of heat and drought stresses; the role of exopolysaccharides as one of bacterial determinants on alleviating stresses; biocontrol activity against soft rot caused by Pectobacterium carotovorum subsp. carotovorum PCC21. Strains H26-2 and H30-3 significantly increased fresh weights compared to a $MgSO_4$ solution; reduced leaf wilting and promoted recovery after re-watering under heat and drought stresses. Chinese cabbages treated with H26-2 and H30-3 increased leaf abscisic acid (ABA) content and reduced stomatal opening after stresses treatments, in addition, these strains stably colonized and maintained their populations in rhizosphere during heat and drought stresses. As well as tested bacterial cells, exopolysaccharides (EPS) of H30-3 could be one of bacterial determinants for alleviation of tested stresses in Chinese cabbages, however, the effects were different to cultivars of Chinese cabbages. In addition to bacterial activity to abiotic stresses, H30-3 could suppress incidence (%) of soft rot in 'Buram-3-ho'. The tested strains were identified as Bacillus aryabhattai H26-2 and B. siamensis H30-3 based on 16S rRNA gene sequence analysis. Taken together, H26-2 and H30-3 could be candidates for both plant growth promotion and mitigation of heat and drought stresses in Chinese cabbage.

• Journal of Environmental Science International
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• v.28 no.8
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• pp.701-707
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• 2019

Highland farming is agriculture that takes place 400 m above sea level and typically involves both low temperatures and long sunshine hours. Most highland Chinese cabbages are harvested in the Gangwon province. The Ubiquitous Sensor Network (USN) has been deployed to observe Chinese cabbages growth because of the lack of installed weather stations in the highlands. Five representative Chinese cabbage cultivation spots were selected for USN and meteorological data collection between 2015 and 2017. The purpose of this study is to develop a weight prediction model for Chinese cabbages using the meteorological and growth data that were collected one week prior. Both a regression and random forest model were considered for this study, with the regression assumptions being satisfied. The Root Mean Square Error (RMSE) was used to evaluate the predictive performance of the models. The variables influencing the weight of cabbage were the number of cabbage leaves, wind speed, precipitation and soil electrical conductivity in the regression model. In the random forest model, cabbage width, the number of cabbage leaves, soil temperature, precipitation, temperature, soil moisture at a depth of 30 cm, cabbage leaf width, soil electrical conductivity, humidity, and cabbage leaf length were screened. The RMSE of the random forest model was 265.478, a value that was relatively lower than that of the regression model (404.493); this is because the random forest model could explain nonlinearity.

• Research in Plant Disease
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• v.15 no.2
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• pp.106-111
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• 2009

Before transplanting Chinese cabbage seedlings, two kinds of eggshell powder were blended into the soil of cabbage field where the club root pathogen, Plasmodiophora brassicae, was infested. The incidence of clubroot disease, the shoot and root growth of cabbages, and soil pH were examined four times at 10 to 13 days interval from transplanting Chinese cabbage. As results, the cabbages treated with eggshell powder without membrane showed the fastest growth in above ground part, and the lowest disease index for clubroot disease. The cabbages treated with eggshell powder with membrane showed better growth than the cabbages of non-treated check, but lower growth than those treated with eggshell powder without membrane. Soil pH started to increase from 3 weeks after soil blending of eggshell powder, and it reached to above 8.0. However, the soil pH of non-treated check stayed at around 6.8. In the experiment to compare the effect of eggshell powder with other calcium compounds, soil-blending of $CaCO_3$ resulted the lowest disease incidence of 1.7 and the registered fungicide, 'flusulfamide', and the resistant variety 'CR Green cabbage' followed with the incidence of 1.9. Cabbages of non-treated check scored the highest disease incidence, 3.4, and that of eggshell powder without membrane was as high as 2.7. However, the growth of Chinese cabbage showed the different pattern to the disease incidence. Chinese cabbages treated with eggshell without membrane recorded the highest average growth, around 2.1 kg. On the other hand, the average growth of CR Green Chinese cabbage was about 2.0 kg, that of flusulfamide-treatment plot was 1.7, and that of non-treated check was as low as 1.3 kg. Soil blending of eggshell powder without membrane did not inhibit the development of clubroot, but increased the growth of cabbage to a great extent. Therefore, it was confirmed that soil blending of eggshell powder before transplanting makes the Chinese cabbage culture possible even in the field infested with club root pathogen.

• Food Science and Preservation
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• v.24 no.2
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• pp.215-220
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• 2017

Cut Kimchi cabbages ($3{\times}3cm$) were dipped in the egg shell solution (0.5% egg shell calcium/0.5% citric acid solution) and stored in the low-density polyethylene (LDPE) film bag at $4^{\circ}C$ for 2 weeks. Using this cut Kimchi cabbage, kimchi was prepared and their physicochemical qualities were investigated. Moreover, their sensory qualities were compared with Kimchi prepared with normal Kimchi cabbages. Egg shell calcium pretreatment (ET) showed the lower weight loss of cabbages than non-treatment (NT), and soluble solid compounds were decreased in all samples. Titratable acidity showed no statistical difference. After making a kimchi using cut Kimchi cabbages stored for 2 weeks no statistical differences in soluble solids and titratable acidities of kimchi stored for 7 days were shown. As a result of sensory test, preference of color was decreased and salted condition of control was the most significantly decreased. Pickled seafood odor of kimchi showed statistical difference, compared with the control. Crispness decreased in all samples. On the other hand, salty flavor and pickled seafood flavor were increased, fresh cabbage flavor, bitter flavor and carbonic flavor were decreased. Overall sensory quality of cut Kimchi cabbage (ETK) didn't show significant difference compare with kimchi prepared with normal cabbage (CON). It is possible to make kimchi with approvable sensory quality using cut Kimchi cabbage treated with egg shell calcium.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.7
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• pp.970-975
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• 2009

The residual amount of 160 kinds of pesticide for multi-analysis methods were analyzed in Baechu cabbages throughout the year by GC/MS. We investigated the 160 kinds of pesticide residues in commercial Baechu cabbages monthly from October 2007 to September 2008. Over the 12 months, the residues were detected in the Baechu cabbages harvested and distributed only in July, August, October and November. The residual amounts were 0.01 ppm Bifenthrin, 0.04 ppm Chlorfenapyr, and 0.03 ppm Bifenthrin in July, October, and November, respectively, and 0.01 2 ppm Bifenthrin in August. All residues were below MRL. These results indicate that the commercial Baechu cabbages are comparatively safe from pesticide residues.

• Journal of Bio-Environment Control
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• v.16 no.3
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• pp.180-185
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• 2007

The effects of selenium (Se) and germanium (Ge) fertilization on the growth and quality of Chinese cabbages cultivated in spring and autumn and peppers cultivated in spring were investigated. $Se\;(Na_2SeO_4)\;and\;Ge\;(GeO_2)$ were supplied 5, 10, or 20 times in an aqueous solution of 0, 2, 4, or $8mg{\cdot}L^{-1}$ during the cultivation of Chinese cabbages and peppers. The fresh weight of Chinese cabbages increased by Ge fertilization with high concentration. But it was not affected by Se fertilization. The content of vitamin C increased by 10 times application with $4mg{\cdot}L^{-1}$ of Se or Ge. The concentration of Se in Chinese cabbage increased according to increasing concentration of Se fertilization. Se concentration was higher in the outer leaves than in the inner leaves. Se concentration in the mesophyll was higher than that in the midrib. Ge fertilization increased the uptake and concentration of Ge in autumn-cultivated Chinese cabbages. Se and Ge fertilization did not affect the fresh weight of peppers. The content of vitamin C in pepper increased by 20 times application of $2mg{\cdot}L^{-1}$ of Se. Vitamin C content in red peppers was twice as much as in green peppers.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.12
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• pp.1767-1772
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• 2009

Brined Baechu cabbages were packed with different films of high density polyethylene (HDPE), aluminium polyethylene (Al/PE), nylon polyamide (Ny/PE), low density polyethylene (LDPE) and permeability-controlled polyethylene (Mirafresh (MF), US patent No. 5972815), and then stored at 4${^{\circ}C}$ for 4 weeks. Changes in quality characteristics of pH, acidity, total bacteria counts, lactic acid bacteria counts, E. coli counts, texture and $O_2$ concentration were determined during the storage. The pH of brined Baechu cabbage packed with Mirafresh (MF) film was 6.25 after 4 weeks from initial pH of 6.80. The acidity of all brined Baechu cabbages increased, however, the increase of the cabbage in MF was the lowest. The levels of total bacteria, lactic acid bacteria and E. coli in the cabbages packed with MF were also lower than the other films. After 4 weeks, of all brined springiness Baechu cabbages decreased, but MF showed relatively high springiness. The $O_2$ concentrations by its permeation through MF were 0.35%-1.00% at 4-25${^{\circ}C}$ after 1 week. In conclusion, MF was found to be the most effective packaging film for brined Baechu cabbage to extend shelf-life.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.11
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• pp.1715-1724
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• 2015

The combined effects of a sanitizer mixture solution and antimicrobial ice on the quality of salted Chinese cabbages were examined. Salted Chinese cabbages were treated with a sanitizer mixture (comprised 50 ppm aqueous $ClO_2$ and 0.5% citric acid), packed in 2% brine and antimicrobial ice, and stored for 12 days at 4 and $10^{\circ}C$. Microbiological data on the salted Chinese cabbages after washing with the sanitizer mixture indicated that the populations of total aerobic bacteria, and yeast and molds decreased by 2.20 and 1.28 log CFU/g after treatment with the sanitizer mixture. In addition, coliforms population of salted Chinese cabbage after 12 days storage at $4^{\circ}C$ in the combined mixture of the sanitizer and antimicrobial ice was 3.22 log CFU/g, which was a significantly different from that of control (5.46 log CFU/g). The combined treatment of sanitizer mixture, antimicrobial ice, and low temperature at $4^{\circ}C$ suppressed reduction of pH and elevation of titratable acidity, resulting in delaying the growth of lactic acid bacteria. Differences in salinity, hardness, and Hunter's $L^*$, $a^*$, and $b^*$ values among treatments were negligible during storage at $4^{\circ}C$. Therefore, this study suggests that a combination of sanitizer mixture, antimicrobial ice treatment, and low temperature storage could improve the microbial safety and quality of salted Chinese cabbages during storage.