• Journal of Bio-Environment Control
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• v.16 no.4
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• pp.348-351
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• 2007

This study was conducted to find out the change of infernal quality, such as vitamin C and nitrate contents in some leaf vegetables grown hydropoincally in different nutrient conditions. Pak-choi (Brassica camperistis L. spp. chinesis Jusl.), chungchima (Lactuca sativa L. var. crispa cv. Chungchima) and romaine (Lactuca sativa L. var. longifolia Lam.) lettuces were cultivated for 2 weeks in 4 different nutrient solutions, such as tap water; no-nutrient, added $NH_4$, discarded $NO_3$, and supplied Yamazaki' solution for lettuce as a control. The growth of leaf vegetables was not different among nutrient solution treatments except tap water. The nitrate content showed the highest in control, and followed by $+NH_4$ treatment, $-NO_3$ and tap water treatment, regardless of kind of vegetables. The vitamin C content in 3 different vegetables showed the opposite result against nitrate content so that the treatment that showing the highest vitamin C content was tap water in romaine and chungchima lettuces, and $-NO_3$ treatment in pak-choi. The vitamin C and the nitrate content showed high correlations; $r=-0.614^*$ in pak-choi, $-0.651^*$ in romaine lettuce, and $-0.804^{**}$ in chungchima lettuce.

• Horticultural Science & Technology
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• v.19 no.2
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• pp.140-144
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• 2001

Field investigations were initiated to determine possible new 'ssam' vegetable that could be grown during the summer season in highland. Korean 'ssam' means cooked rice in vegetables. The 'ssam' vegetable is called that those leaves has been used for wrapping at meal. Seventeen leafy vegetables were studied, including chard (Beta vulgaris L. var. flavescens DC.), leaf broccoli (Brassica oleracea L. var. italica), Chinese leek (Allium tuberosum Rottl.), Japanese hornwort (Cryptotaenia japonica Hassk), red leaf mustard (Brassica juncea L.), green leaf mustard (Brassica juncea L.), leaf parsley (Petroselinum crispum Nijim), pakchoi (Brassica campestris L. ssp. chinensis Jusl.) tatsoi (Brassica campestris var. narisoma), kale (Brassica oleracea var. acephala), collard (Brassica oleracea var. acephala), Korean mint (Agastache rugosa O. Kuntze), romaine lettuce (Lactuca sativa L. var. longifolia Lam.), red leaf chicory (Cichorium intybus L. var. folisum), red chicory (Cichorium intybus L. var. folisum), green leaf chicory (Cichorium intybus L. var. folisum), and sprouting broccoli (Brassica oleracea L. var. italica). Date of the first harvest in 1999 was July 10th in chard, leaf broccoli, red mustard, mustard, leaf parsley, pakchoi, tatsoi, kale, collard, Korean mint, red leaf chicory, red chicory, green leaf chicory, and sprouting broccoli. Date of the first harvest for Chinese leek, Japanese hornwort, and romaine lettuce was from the middle of June to the late of August. Based on ratings on marketable yield, we found good leaf shape, taste and yield in chard, red leaf mustard, green leaf mustard, pakchoi, tatsoi, romaine lettuce, red leaf chicory, red chicory, and green leaf chicory. Even though the most of all these vegetables were obtained high scores by test panels in shape, taste and quality, but some of them revealed inadequate leaf size as a 'ssam' vegetable. That problem will be solved by control of harvesting time. On the basis of this observation, chard, red leaf mustard, green leaf mustard, pakchoi, tatsoi, romaine lettuce, red leaf chicory, red chicory, and green leaf chicory were rated as promising 'ssam' vegetable by analysis of profits, adaptation, and quality.

• Korean Journal of Ecology and Environment
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• v.47 no.1
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• pp.32-40
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• 2014

This study was conducted to evaluate the growth response of economical six leafy vegetables that are crown daisy, pak-choi and four kinds of lettuce (Red leaf lettuce, Green leaf lettuce, Head lettuce, Romaine lettuce) by light treatment of LED in plant factory. The light treatments were composed of red, blue, red+farred, red+blue, red+blue+white LEDs, irradiation time ratio of the red and blue LED per minute (1 : 1, 2 : 1, 5 : 1, 10 : 1), and duty ratio of mixed light (100%, 99%, 97%). The following results were obtained in different LED light sources treatments: Shoot biomass and S/R ratio of romaine lettuce were the highest under mixed red+blue LEDs. S/R ratio of head lettuce was higher under mixed red+blue+white LEDs than red+blue LEDs. The others showed no difference in LED light treatment. Shoot biomass, total biomass and S/R ratio of green lettuce, head lettuce and pak-choi were highest in the higher red ratio (5 : 1) on irradiation time of red : blue LED ratios. By the different duty ratio (red+blue and red+blue+white LEDs), Under the mixed light of red+blue, shoot and root biomass of crown daisy and romaine lettuce were high in duty ratio of 100% and 99%, and S/R ratio was highest in all the 6 kinds in duty ratio of 97%. All the 6 kinds showed a fine growth state in low duty ratio (97%). Green lettuce, romaine lettuce and pak-choi showed relatively high shoot biomass and total biomass in low duty ratio of 97% under the mixed light of red+blue+white. S/R ratio of romaine lettuce and head lettuce were highest in the duty ratio of 97% with red+blue+white LEDs. Thus, we can cultivate stably without reference to external factors, if we use appropriate light sources and light quality in closed-type plant factory.

• Journal of Bio-Environment Control
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• v.24 no.4
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• pp.271-274
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• 2015

The objective of this study was to investigate the effects of composition of nutrient solution on the growth and quality of baby leaf vegetables (tat soi, romaine lettuce, beet, and red radish) hydroponically cultivated in plant factory. The seeds of four vegetable crops were sown in urethane sponges and cultivated for 14 days in a plant factory. Light intensity and photoperiod were $110{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ and 16 h, respectively; and air temperature in photo/darkperiod was maintained at $25/20^{\circ}C$. Tap water was used for irrigation for 7 days after sowing, and then plants were irrigated for 7 days using tap water and the nutrient solutions of Korea Wonshi, Japan Enshi, and Yamazaki for lettuce. At 14 days after sowing, the fresh weight of tah soi was highest in the nutrient solution of Yamazaki for lettuce, and there were no significant differences among nutrient solutions in beet and red radish. When we compared leaf color using Hunter's a value, the nutrient solution of Korea Wonshi and Japan Enshi increased green color in baby leaf vegetables, while the nutrient solution of Yamazaki for lettuce increased red color. Total phenolic content of romaine lettuce was highest in the nutrient solution of Korea Wonshi, but tat soi, beet, and red radish showed no significant differences among nutrient solutions in total phenolic contents. From these results, we suggest that using the nutrient solution of Korea Wonshi can enhance the growth and quality of romaine lettuce and the nutrient solution of Yamazaki for lettuce is appropriate for enhancing the growth and red color of beet and red radish in plant factory.

• Proceedings of the Korean Society of Crop Science Conference
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• 2021.04a
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• pp.135-135
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• 2021

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.27 no.3
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• pp.187-192
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• 2021

This study was conducted to compare the quality of baby leaves grown under several temperature conditions and the storage properties of MA storage for romaine lettuce. It was grown for 5 weeks under an artificial light source (200 µmol·m^-2·s^-1) in a chamber at 21℃, 28℃, and 35℃. The growth and quality of red romaine lettuce that grown in different temperatures were investigated at the end of cultivation, and the oxygen, carbon dioxide, and ethylene concentrations in the 20,000 cc OTR film and perforated film packed with lettuces were measured for 36 and 12 days, respectively. The red romaine lettuce baby leaf was examined for color, chlorophyll, and visual quality at the end of storage. The maximum quantum yield of baby leaf grown in different temperatures at 7days before the harvest was higher at 21℃ and 28℃ growth temperature treatments. On harvest day, the leaf length measured was longest at 28℃, and the leaf width was wider at 21℃ and 28℃, and the number of leaves was similar to 5-6 at all cultivation temperatures. Leaf weight, root weight, and dry weight were found to be higher at 21℃, and tended to decrease as the cultivation temperature increased. The concentration of ethylene in the film of the MA storage treatments was maintained at 1~2 µL·L^-1 until the end of storage in all treatments regardless of the cultivation temperature. Oxygen concentration in the MA treatment used 20,000 OTR film was maintained at around 19.5%, and carbon dioxide concentration around 1% that was satisfied the CA conditions. Both Hunter a^* and b^* values were generally higher in the MA storage treatment at the end of storage day. The chlorophyll content was decreased as the cultivation temperature increased, and was lower in the MA storage treatment than in the perforated film treatment. Visual quality was 3 points or higher in the MA storage treatment at 21℃ growth treatment, and it was maintained marketability. As the above results, the growth of baby leaves of romaine lettuce was the best at 21℃ treatment, and the lower the cultivation temperature, the longer the shelf life. And it was possible to extend the shelf life by 3 times by showing excellent visual quality at the MA storage treatment that satisfies the carbon dioxide concentration of CA condition until the end of storage day.

• Journal of Bio-Environment Control
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• v.16 no.4
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• pp.420-425
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• 2007

This study was conducted to find out the effect of vitamin C treatments on the storability of several baby vegetables; endive, green romaine lettuce, pak-choi, red romaine, lollo rosa, and ssamchoo. The vitamin C was treated by the foliar spray which was carried out 3 times before harvest or dipping in vitamin C solution for 5 minutes after harvest. The vitamin C contents of 6 different baby vegetables were higher in vitamin C treatments than control, whereas the difference of vitamin C content between treatments was disappeared after storage. The fresh weight of ssamchoo and lollo rosa lettuce treated by vitamin C was maintained higher than that of control. There was not significant difference in visual quality among treatments, though some of baby vegetables treated by washing with vitamin C showed better visual quality than the others. The contents of carbon dioxide, oxygen and ethylene in MAP with baby vegetables did not show any difference among treatments. As the result, high concentrated vitamin C treatment, such as the foliar spray and washing (dipping) had a role of increasing functionality, but the enhanced functionality, high vitamin C, did not affect storability in baby vegetables.

• Journal of Food Hygiene and Safety
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• v.28 no.4
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• pp.306-311
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• 2013

This study was conducted to investigate spoilage bacteria on organic and conventional fresh produce in Korea. Three samples (perilla leaf, cabbage, and romaine lettuce) of organic and conventional fresh produce were stored at $4^{\circ}C$ for 14 days and examined for spoilage bacteria on TSA. Isolated bacteria from organic and conventional fresh produces were identified using 16S rRNA sequencing method. Population of total aerobic bacteria on conventional perilla leaf, cabbage, and romaine lettuce were 7.59, 7.01, and $5.84{\log}_{10}CFU/g$, and populations of total aerobic bacteria were 6.72, 6.15, and $5.85{\log}_{10}CFU/g$, for organic perilla leaf, cabbage, and romaine lettuce, respectively. Major spoilage bacteria of organic and conventional fresh produces were similar however their levels were little different. For example, a major spoilage bacterium resulting the highest level on conventional perilla leaf was Stenotrophomonas maltophilia whereas that was Microbacterium sp. for organic produce. From these results, microflora or spoilage microorganism could be different depending on their cultivation types as conventional or organic produces and this information might be used for developing effective preservation method for different types of fresh produce.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2005.10a
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• pp.127-130
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• 2005

• Journal of Nutrition and Health
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• v.50 no.2
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• pp.133-141
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• 2017

Purpose: The objective of this study was to examine the association of temperature-fluctuation with freshness quality in various foods. Methods: We investigated the effects of storage conditions on antioxidant activities of cherries and romaine lettuce during storage at $0.7{\pm}0.6^{\circ}C$, $1.2{\pm}1.4^{\circ}C$, and $1.6{\pm}2.8^{\circ}C$. Cherries and romaine lettuce were stored for a period of 9 days and 7 days, respectively. We also analyzed the effects of storage conditions on fresh quality of beef and salmon during storage at $-0.3{\pm}0.8^{\circ}C$, $-0.6{\pm}2.3^{\circ}C$, and $-1.5{\pm}4.4^{\circ}C$. Both of them were stored for a period of 14 days. Results: The amount of water loss was highest in beef, and the microbial count was also the highest at $-1.5{\pm}4.4^{\circ}C$. In the case of salmon, there was no difference in water loss according to storage, and TBA value was significantly increased at $-1.5{\pm}4.4^{\circ}C$. Moisture retention was the highest at $0.7{\pm}0.6^{\circ}C$ in both romaine lettuce and cherry samples. The contents of polyphenol and flavonoid were significantly higher in cherries, and content of polyphenols in romaine lettuce was significantly higher at $0.7{\pm}0.6^{\circ}C$ (p < 0.05). DPPH activity decreased in the order of $0.7{\pm}0.6^{\circ}C$ > $1.2{\pm}1.4^{\circ}C$ > $1.6{\pm}2.8^{\circ}C$ over 7 days. Conclusion: The results indicate that temperature-fluctuation may affect qualities of foods stored in a refrigerator.