• The Korean Journal of Food And Nutrition
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• v.27 no.5
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• pp.897-905
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• 2014

The foliage of sweet potato [Impomoea batatas (L.) Lam] is an excellent source of food material due to the functional components of polyphenol and carotenoid. In this study, the lightness (L-value), polyphenol contents, and DPPH radical scavenging activity of the foliage of Shinwhangmi, Hayanmi and Suioh cultivars harvested after different cultivation periods (60, 90 and 120 days after planting) and according to tip locations (1st~5th, 6th~10th, 11th~15th tips) were investigated. As a result, Shinwhangmi showed a lower lightness value (60 days after planting and 1st~5th tips). The longer the cultivation periods and the closer the tips, the higher the contents of polyphenol and DPPH radical scavenging activity were in lyophilized foliage of Shinwhangmi, Hayanmi and Suioh. In the 1st~10th tip of Shinwhangmi, Hayanmi and Suioh cultivated for 90 days and dried by 2 step hot-air (1st: $70^{\circ}C$ for 8 hr, 2nd: $80^{\circ}C$ for 4 hr), the polyphenol and ${\beta}$-carotenoid contents were 5.0, 3.9 and 4.0 mg/g and 75.6, 71.6 and 63.1 mg/g, respectively. The DPPH radical scavenging activities and ABTS radical scavenging activities ($EC_{50}$) were 0.29, 0.36 and 0.33 mg and 0.12, 0.15 and 0.11 mg, respectively. These antioxidative activities were over two times stronger than spinach.

• Korean Journal of Food Science and Technology
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• v.44 no.6
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• pp.728-735
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• 2012

Makgeolli is the oldest Korean traditional wine made from rice, and contains 6-8% alcohol. Also, nuruk is traditionally prepared by exposing moistened ground wheat or rice to the air, and there contained airborne microorganism. In this study, purple sweet potato (PSP) was used as a raw material in the rice nuruk- and makgeolli-making processes. PSP rice nuruk (RN) was made with rice and 0-10% (w/w) PSP, and the characteristics of makgeolli were studied during fermentation. The pH during fermentation decreased from 4.27 (0% PSP-RN), 4.59 (2.5%), 4.50 (5.0%), 4.46 (7.5%), and 4.43 (10.0%) of initial fermentation day to 4.12, 3.82, 3.67, 3.71, and 3.66, respectively, at day 7. The sugar contents increased from $0.4^{\circ}Bx$ of the initial day to $8.0-8.4^{\circ}Bx$, and the levels of alcohol increased to 13.0% (0% PSP-RN), 13.2% (2.5%), 12.8% (5.0, 7.5, and 10.0%) by day 7, respectively. In addition, the contents of soluble anthocyanins and phenolics increased from 0.001-0.121 and 0.2-0.27 g/L on the initial fermentation day to 0.002-0.166 and 1.65-1.87 g/L, corresponding to increases in levels of antioxidant activities of 20-50%, respectively.

• The Plant Pathology Journal
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• v.35 no.6
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• pp.674-683
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• 2019

Some species of the Trichoderma genus are reported as the major problem in oak wood mushroom production in Korea. In spite of economic loss by the fungi, scientific information on airborne Trichoderma species is not much available. To generate information for disease management development we analyzed airborne Trichoderma. A total of 1,063 fungal isolates were purely obtained from indoor air sampling of cultivation houses used for oak wood mushroom using sawdust media. Among the obtained isolates, 248 isolates were identified as Trichoderma fungi including T. harzianum, T. atroviride, T. citrinoviride, and T. pseudokoningii, by morphological and molecular analysis. T. harzianum was dominant among the four identified species. All the four Trichoderma species grew fast on solid nutrient media tested (potato dextrose agar [PDA], malt extract agar [MEA], Czapek's Dox + yeast extract agar [CYA] and cornmeal dextrose agar). Compact mycelia growth and mass spore production were better on PDA and CYA. In addition, T. harzianum and T. citrinoviride formed greenish and yellowish mycelium and spores on PDA and CYA. Greenish and yellowish pigment was saturated into PDA only by T. pseudokoningii. These four Trichoderma species could produce extracellular enzymes of sawdust substrate degradation such as β-glucosidase, avicelase, CM-cellulase, amylase, pectinase, xylanase, and protease. Their mycelia inhibited the growth of oak wood mushroom mycelia of two tested cultivars on dual culture assay. Among of eleven antifungal agents tested, benomyl was the best to inhibit the growth of the four Trichoderma species. Our results demonstrate that the airborne Trichoderma fungi need to be properly managed in the cultivation houses for safe mushroom production.

• Korean Journal of Food Science and Technology
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• v.26 no.6
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• pp.805-813
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• 1994

Zucchini slices, sweet potato stems, taro stems, and platycodon treated with various methods such as dipping in citric acid solution, sulfite solution, or sulfur fumigation were dried by the natural sun drying method or the forced air drying method at 50, 70, 90, or $105^{\circ}C$. Mold growth of the dried vegetables and sensory quality of the dried and rehydrated vegetables were investigated. Limiting moisture contents to prevent mold growth over 3 month storage under room temperature were 15, 20, 25, and 15% for zucchini slices, sweet potato stems, taro stems, and platycodon, respectively. The chlorophyll containing vegetables dehydrated by the forced hot air showed better sensory quality than those by the natural sun. Among the pretreatments, dipping in the sulfite solution provided the best sensory quality to the dried vegetables. The sensory quality of dried platycodon was improved to a small extent by sulfur fumigation and sulfite solution treatment. The sensory quality of the dried platycodon was not found to be affected by the drying methods. All the tested vegetables dried at $105^{\circ}C$ had the worst sensory quality. Except drying temperature of $105^{\circ}C$, the lower the drying temperature, the better the sensory quality and the rehydration rates were obtained for the tested vegetables except platycodon. The sensory quality of the platycodon was little affected by the drying temperature tested in the range of $50{\sim}90^{\circ}C$.

• Journal of Bio-Environment Control
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• v.12 no.3
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• pp.147-152
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• 2003

This study was conducted to analyze the energy balance in closed transplants production system (CTPS) for the production of high quality transplants. Potato (Solanum tuberosum L. cv. Dejima) plug seedlings were grown for 15 days at air temperature of 20$^{\circ}C$, relative humidity of 70%, photoperiod of 16/8 h, and photosynthetic photon flux (PPF) of 200 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ following 5 days of tooting in CTPS. Electric energy consumption was 46% for lighting, 35% for cooling, 16% for heating, 2% for air circulation, and 1% for humidifying. The electric energy utilization efficiency and the short-wave energy utilization efficiency were 0.5% and 5.4%, respectively. These results suggest that CTPS has the feasibility for the commercial production of potato plug seedlings if the electric energy consumption in CTPS is reduced and the electric energy utilization efficiency is increased.

• Korean journal of applied entomology
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• v.43 no.4 s.137
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• pp.323-328
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• 2004

These studies were carried out to investigate the fumigation and contact toxicities of spearmint oil (Mentha spicata) against adults of greenhouse whitefly, Trialeurodes vaporariorum and sweet-potato whitefly, Bemisia tabaci. And we carried out the constituent analysis of spearmint oil using gas chromatograph (GC) and gas chromatograph mass spectrometry (GC/MS). Spearmint oil showed $99.1\%,\;91.7\%,\;41.1\%$ fumigation toxicity against T. vaporariorum adults at $10{\mu}L/954mL,\;5{\mu}L/954mL,\;1{\mu}L/954mL$ air concentration, respectively. In case of B. tabaci adults, spearmint oil showed $100\%,\;100\%,\;61.3\%$ fumigation toxicity, respectively. However, spearmint oil showed < $30\%$ contact toxicity against adults of T. vaporariorum and B. tabaci. Through the constituent analysis using GC and GC/MS, we confirmed main constituents of spearmint oil were limonene ($16.1\%$), ${\gamma}$-terpinene($13.8\%$), ${\rho}$-cymene($5.8\%$), 3-octanol($6.9\%$), carvone($40.9\%$). Carvone, major constituent of spearmint oil, also showed $100\%$ fumigation toxicity at $10{\mu}L/954mL$ air concentration.

• Journal of Bio-Environment Control
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• v.13 no.1
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• pp.51-55
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• 2004

The most commonly used inorganic nutrient compositions such as Murashige & Skoog medium have been optimized for heterotrophic growth. Therefore, they may not be optimal for photomixotrophic and photoautotrophic growth of plantlets. In photomixotrophic micropropagation, emdium sugar level is often lowered, while light and $CO_2$ levels in vessel are raised, and chlorophyllous explants are used to facilitate photosynthetic carbon acquisition. In a factorial experiment effect of addition (+) and omission(_) of organic materials (OM, 0.5 g ${\cdot}$ $m^{-3}$ each of thiamine, nicotinic acid and pyridoxine and 100 ${\cdot}$ $m^{-3}$ myo-inositiol) combined with three sucrose levels (0, 15, and 30 kg ${\cdot}$ $m^{-3}$) was tested on the growth of potato plantlets. Each of nodal cuttings with a leaf was cultured on 0.1${\times}$$10^{-4}m^{-3}$) MS agar ( 8 kg ${\cdot}$ $m^{-3}$) medium (pH 5.80 before autoclave) in glass test tubes (100 mm${\times}$25mm) capped with a sheet of transparent film with a 6 mm diameter gas permeable filter (5.1 air exchanges ${\cdot}$$h^{-1}$). Cultures were maintained in a room for 27 days at $23^{\circ}C$, 50% RH, 350-450${\mu}mol\;{\codt}\;mol^{-1}CO_2$, 16 h ${\cdot}$ $d^{-1}$ photoperiod at 13${\mu}mol\;{\codt}\;m\;{\codt}\;s^{-1}$ PPFD provided by white cool fluorescent lamps. Growth of potato plantlet in the +OM and -OM treatments were similar, while medium pH was 0.2 scale lower in the latter. Dry weight, % dry matter, and stem diameter enhanced, while shoot to root dry weight ratio, leaf area, chlorophyll concentration per gram dry weight, and medium pH decreased with increasing initial sucrose level. Interaction between OM and sucrose levels was observed in shoot length and medium pH. Results indicate that OM can be omitted from the medium without detrimental effect while addition of sucrose was beneficial for the photomixotrophic growth of potato plantlets under raised light and $CO_2$.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.355-358
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• 2001

Selection of optima] nutrient sources and cultural methods for liquid spawn culture of Flammulina velutipes were carried out. The optimal temperature and pH for mycelial growth of F. velutipes were $20^{\circ}C$ and 6.0 to 7.5. respectively. In the 250ml ${Delta}$-flask culture. the amount of inoculum and culture period for the optimal mycelial growth of F. velutipes were 3 mycelial disks(diametcr 6mm) and 6 days, respectively. For the mass production of submerged culture. the optimal inoculum amount and aeration rate of F. velutipes were 5%(inoculum vol/medium vol.) and l.0vvm(vol of air/vol. of medium/min), respectively.

• The Plant Pathology Journal
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• v.15 no.6
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• pp.345-347
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• 1999

A scab disease on eggplant (Solanum melongena L. cv. Chukyang) in plastic film houses around Kimhae area in Korea during the winter season of 0998-1999. The disease started on leaves with small dark brown spots which were gradually expanded to 1 to 3 mm diameter lesions. Later, the central parts of the lesions became collapsed and detached to make holes. Dark brown mold was grown out of the lesions on the lower side of leaf. Numerous conidia were produced on the lower side of leaf. Numerous conidia were produced on the diseased leaves and appeared to be readily dispersed in the air. A fungus was isolated from the diseased leaves, and tested for Koch's postulates to prove the causal agent of the desease. The isolated fungus grew on potato dextrose agar, forming greenish black to pale brown colonies. Conidia were ellipsoidal, fusiform or subspherical, mostly one-celled but occasionally septated, and formed in long branched chains on the erected conidiophores which were pale olevaceous brown and variable in length between 12.4 and $393.4\mu\textrm{g}$. The fungus was identified as Cladosporium cucumerinum Ellis Arthur based on the above morphological characteristics examined. The optimum temperature for mycelial growth and conidial formation was about 20 to $25^{\circ}$. In addition to cucumber, the fungus was also pathogenic to watermelon, pumpkin and oriental melon. This is the first report on the scab disease of eggplant in Korea.

• Journal of Biosystems Engineering
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• v.38 no.1
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• pp.41-47
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• 2013

Purpose: The objectives of this study were to construct the solar drying system with evacuated tubular solar collector and to investigate its performance in comparison with indoor and outdoor dryings. Methods: Solar drying system was constructed with using CPC (compound parabolic concentrator) evacuated tubular solar collector. Solar drying system is mainly composed of evacuated tubular solar collector with CPC reflector, storage tank, water-to-air heat exchanger, auxiliary heater, and drying chamber. Performance test of solar drying system was conducted with drying of agricultural products such as sliced radish, potato, carrot, and oyster mushroom. Drying characteristics of agricultural products in solar drying system were compared with those of indoor and outdoor ones. Results: Solar drying system showed considerable effect on reducing the half drying time for all drying samples. However, outdoor drying was more effective than indoor drying on shortening the half drying time for all of drying samples. Solar drying system and outdoor drying for oyster mushroom showed the same half drying time. Conclusions: Oyster mushroom could be dried easily under outdoor drying until MR (Moisture Ratio) was reached to about 0.2. However, solar drying system showed great effect on drying for most samples compared with indoor and outdoor dryings, when MR was less than 0.5.