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Young-Sang Lee, Yong-Sun Lee and Chang-Sung Kang

The cut Lilium oriental hybrid `Casablanca' was pulsed with chitosan (MW = 5000–10,000), grapefruit seed extract (GFSE), GA, and sucrose and enclosed with a polyethylene (PE) film of different perforations before packing into a cardboard box. Simulated transport (ST) was conducted by storing plants at 22 °C for 3 days, and the flower opening and weight loss during ST as well as post-ST floral longevity were evaluated. Pulsing with 600 ppm chitosan effectively reduced open flower percentage and weight loss during ST by 6.5% and 36%, respectively. The same concentration of chitosan, however, slightly decreased post-ST floral longevity. Adding 8% sucrose and 100 ppm GA enhanced chitosan effects. In contrast to chitosan, 500 ppm GFSE increased flower opening during ST. Enclosing plants with perforated PE film significantly reduced weight loss during ST, but increased flower opening although no ethylene accumulation over 0.08 ppm was detected in enclosed atmosphere. The opening of flowers during ST also increased in proportion to the time delay between harvest and pulsing.

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Young-Sang Lee, Yong-Sun Lee and Chang-Sung Kang

The practicality of utilizing chitosan (MW = 5000-10,000) as a natural antimicrobial compound to reduce soybean sprout rot was tested. Soybean seeds were soaked for 6 h in solutions containing different levels of chitosan and acetic acid (glacial), and cultivated at 25 °C for 5 days. Soaking seeds with 1000 ppm chitosan increased germination percentage, hypocotyl thickness, total length, and fresh weight of sprouts by 4%, 5%, 2%, and 1%, respectively. The total sprout yield was increased by chitosan in a concentration-dependent manner in that 1000 ppm chitosan resulted in 8% increment of total yield (7.47 kg sprouts/kg seed). Compared to control (13.8%), chitosan significantly reduced sprout rot percentage to 7.0%, and consequently enhanced the marketable sprout yield by 39%. Although 100 ppm acetic acid also decreased sprout rot percentage to 11.8%, its yield-increasing effects were not as prominent as chitosan.

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Jae-Ho Lee, Hyun-Il Cha, Sang-Mi Moon, Kyoung-Shim Cho and Young-Sang Lee

Red pepper, as an ingredient of Kimchi, is an important horticultural crop in Korea, and capsaicinoid content is a major factor determining the pungent quality of red pepper. To clarify the factors affecting capsaicinoid content, 122 red pepper samples of 24 varieties were collected from 21 cultivation sites in Cheongyang area, South Korea, and their nordihydrocapsaicin (NDC), capsaicin (CAP), and dihydrocapsaicin (DHC) contents were evaluated by using an HPLC. The average content of NDC, CAP, and DHC were 4.8, 74.2, and 26.5 mg/100 g, respectively, and its relative composition ratios were slightly affected by variety or cultivation places. In most cultivation places, capsaicinoid contents showed significant dependence upon variety, in that cv. WangJangKum (225.5 mg/100 g) exhibited 6.2-fold higher total capsaicinoid contents when compared to cv. ChonHaTongIl (36.2 mg/100 g). Even the same cultivar (e.g., WangDaeGum) exhibited almost 2-fold variations according to cultivation places, indicating the dependence of capsaicinoid content of red peppers upon the cultivation sites. Analysis of variance revealed significant variety–cultivation place interactions in CAP, DHC, and total capsaicinoid contents, but not in NDC. This data suggests the necessity of more-careful selection of variety and cultivation place corresponding to the expected pungency of harvested red peppers.

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Young-Sang Lee, Yong-Ho Kim and Sung-Bae Kim

To study the effects of chitosan on the productivity and nutritional quality of soybean (Glycine max L.) sprouts, soybean seeds were soaked in solutions containing 1,000 ppm chitosan of low (<10 kDa), medium (50 to 100 kDa), or high (>1,000 kDa) molecular weight, and the respiration, growth, and vitamin C content of the sprouts were subsequently evaluated. Sprouts treated with high molecular weight chitosan exhibited a significant increase in respiration, 5%, within 1 day of treatment. Chitosan effectively increased the growth of the sprouts: sprouts treated with high molecular weight chitosan showed increases of 3%, 1%, 3%, 1%, and 12% in the total length, hypocotyl length, root length, hypocotyl thickness, and fresh weight, respectively, as compared to a control. The growth-improving effects of chitosan were proportional to the molecular weight of the molecule used in the treatment. Chitosan treatment did not result in any significant reduction in vitamin C content or postharvest chlorophyll formation, traits that determine the nutritional and marketing values of soybean sprouts. All these results suggest that soaking soybean seeds in a solution of chitosan, especially of high molecular weight, may effectively enhance the productivity of soybean sprouts without adverse effects on the nutritional and postharvest characteristics.

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Young Sang Lee, G Mitiku and A.G. Endress

The hypothesis that Al3+ interferes with membrane biophysical properties has been tested. Plasma membrane expansion/contraction in protoplasts isolated from red beet was induced by decreasing or increasing the osmolarity of extracellular solutions. The percentage of Iysed protoplasts was measured to characterize the effects of Al3+ on the ability of protoplasts to increase their plasma membrane surface area. In control solutions (800 mM sorbitol), 31.4% of protoplasts Iysed following osmotic dilution from 1200 mM. Al3+ treatment (5 mM) decreased the proportion of Iysed protoplasts by 7.7% and Ca2+ (5 mM) by 17% compared to control. Lanthanum (La3+), however, proved to be the most efficient ion for protection against Iysis (3.3%). Under hypertonic solutions, Al3+ treatment helped protoplasts maintain their roundness, diameter, and cross-sectional area compared to the control (1.5 M sorbitol), thus, altering the protoplasts “roundness” as determined by image analysis parameters. The results suggest that a decrease in the proportion of Iysed protoplasts in the presence of Al3+ may be induced due to changes in membrane permeability to water.

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Kyoung-Shim Cho, Hyun-Ju Kim, Sang-Mi Moon, Hyun-Gu Choi and Young-Sang Lee

Traditionally fatty acid composition used to be analysed by GC and the sample preparation consisted of lipid extraction from sample and subsequent methyl esters preparation, which are time-consuming and cumbersome. As an alternative, simultaneous extraction/methylation methods are being developed for rapid and simplified sample preparation. To optimize one-step extraction/methylation method for analysis of fatty acid composition in brown rice and adlay seeds, various factors, such as sample to reaction solution ratio, reaction time and temperature, and shaking intensity, were altered and resultant fatty acid composition data were evaluated in comparison with previous reports. The ratio of sample weight to reaction solution volume was the most critical factor in that higher sample to reaction solution ratio caused overestimation of palmitic acid and linoleic acid composition, resulting in underestimation of oleic acid. Lower reaction temperature also induced overestimation of linoleic acid and underestimation of oleic acid. Reaction duration and the intensity of shaking prior to and during the reaction, however, induced no significant changes in analysis results. In conclusion, the optimum condition for brown rice was mixing 5 grains (about 0.2 g) of brown rice with 680 μL of methylating mixture and 400 μL of heptane, followed by reaction at 80 °C for 2 hours.

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Shiva Ram Bhandari, Bo-Deul Jung, Hum-Young Baek and Young-Sang Lee

To understand ripening-dependent changes in phytonutrients, five commercial cultivars of red peppers (Capsicum annuum L.) grown in an open field in Taean, South Korea, were selected and their fruits were harvested at green mature (GM), intermediate breaker (BR), and red ripe (RR) stages and their phytonutrient contents and antioxidant activities were compared. Three major patterns in relation to ripening progress were observed. First, continuous increases were observed in vitamin C, total phenol, vitamin E (especially α-tocopherol), total free sugar, β-carotene, linolenic acid content, and antioxidant activity. Second, decreasing patterns were observed in phytosterols (campesterol, stigmasterol, and β-sitosterol) and linoleic acid. Third, total flavonoid and squalene contents were relatively higher at the BR stage compared with the GM and RR stages. These results indicate that each phytonutrient has a unique pattern of accumulation and degradation during the fruit-maturing process. Unlike the mentioned phytonutrients, which showed similar patterns in all tested cultivars, capsaicinoids exhibited quite different patterns of ripening-dependent changes among the cultivars. Throughout the ripening processes, positive correlations with antioxidant activity were observed in vitamin E (r = 0.814**), β-carotene (r = 0.772*), vitamin C (r = 0.610**), and total phenol (r = 0.595**) contents, whereas capsaicinoids, total flavonoid, and phytosterols exhibited no or slightly negative correlations. In conclusion, the ripening of red pepper fruits is accompanied by continuous increments in various phytonutrients and subsequent antioxidant activity.

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Kyoung-Shim Cho, Hyun-Ju Kim, Jae-Ho Lee, Jung-Hoon Kang and Young-Sang Lee

Fatty acid is known as a physiologically active compound, and its composition in rice may affect human health in countries where rice is the major diet. The fatty acid composition in brown rice of 120 Korean native cultivars was determined by one-step extraction/methylation method and GC. The average composition of 9 detectable fatty acids in tested rice cultivars were as followings: myristic acid; 0.6%, palmitic acid; 21.2%, stearic acid; 1.8%, oleic acid; 36.5%, linoleic acid; 36.3%, linolenic acid; 1.7%, arachidic acid; 0.5%, behenic acid; 0.4%, and lignoceric acid; 0.9%. Major fatty acids were palmitic, oleic and linoleic acid, which composed around 94%. The rice cultivar with the highest linolenic acid was cv. Jonajo (2.1%), and cvs. Pochoenjangmebye and Sandudo showed the highest composition of palmitic (23.4%) and oleic acid (44.8%), respectively. Cultivar Pochuenjangmebye exhitibed the highest composition of saturated fatty acid (28.1%), while cvs. Sandudo and Modo showed the highest mono-unsaturated (44.8%) and poly-unsaturated (42.4%) fatty acid composition, respectively. The oleic acid showed negative correlation with palmitic and linoleic acid, while positive correlation between behenic and lignoceric acids was observed.

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Yun-Chan Huh, Du-Hyun Kim, Sang-Gyu Lee, Kyoung-Sub Park, Dong-Kum Park, Young-Hoe Woo and Jung-Myung Lee

Growth response of `Sambok Honey' watermelon grafted onto different rootstocks, including four Citrullus rootstocks and three other cucurbitaceous rootstocks, was evaluated at low and normal temperature regimes. Marked reduction in plant growth rate was observed in plants grown at low temperatures as compared to those grown at normal or optimal temperatures. Relative growth reduction rates were 40% to 48% for vine length, 39% to 51% for total leaf area, 37% to 60% for shoot fresh weight, and 50% to 79% for shoot dry weight, respectively. Watermelon rootstock PI 482322 showed comparable plant growth as the most popular rootstock (Shintozwa pumpkin) even at low temperatures. `Sambok Honey' watermelon grafted onto watermelon hybrids `PI 271969 × PI 296341' and `PI 271769 × Calhoun Gray', showed comparable plant growth as FR Dantos bottle gourd rootstock. Index of growth ability at low temperature (IGALT), which was calculated on the basis of reduced rate of vine length, dry weight, and leaf area, was comparatively high in C. martinezii, Shintozwa, PI 482322, and `PI 271769 × PI 296341' rootstocks (50% or higher) and lowest in own-rooted `Sambok Honey' or in watermelon plants on `Knight' rootstock. Watermelon hybrids `PI 271969 × PI 296341' and `PI 271769 × Calhoun Gray' exhibited better or at least comparable growth at low temperatures as compared to `FR Dantos', thus confirming the feasibility of using watermelon rootstocks even in winter greenhouse conditions.