This study assessed dried vegetables derived from sweet potato petioles to promote the use of typically discarded aerial parts. The length (18.25 to 35.00 cm) and thickness (4.59 to 6.66 mm) of the petioles varied by variety, with ‘Hophungmi’ and ‘Tongchaeru’ showing promise for dried vegetable processing due to their longer and thicker petioles. In terms of color, ‘Hophungmi’ and ‘Shinmi’ exhibited high lightness, ‘Tongchaeru’ and ‘Hayangmi’ displayed strong redness, and ‘Pungwonmi’ had high yellowness. Rehydration rates and hardness increased over the harvest period, with ‘Pungwonmi’ and ‘Tongchaeru’ demonstrating excellent rehydration capacity. Additionally, ‘Hayangmi,’ ‘Shinmi,’ ‘Tongchaeru,’ and ‘Hophungmi’ maintained lower hardness levels, appealing to consumers who prefer a softer texture. Notably, the substantial polyphenol content (10.70 to 16.20 mg GAE/g) and flavonoid content (4.79 to 8.11 mg CE/g), along with antioxidant activity (DPPH: 1.11 to 2.14 mg, ABTS: 5.51 to 7.78 mg TE/g), indicate their potential as antioxidant-rich functional foods. This research supports the development of dried vegetable products tailored to consumer preferences.
한국은 역사적으로 아주 오랜 시간 중국과 교류하며 정치, 경제, 사회, 문화 전반에 걸쳐 많은 영향을 주고받았다. 이에 국가 차원의 중국어 교 육 역시 한반도 역사와 궤를 같이한다고 볼 수 있다. 그러나 지금까지 국내에서 진행된 현대 중국어 교육 및 교육과정과 관련한 연구는 대개 1990년대 제6, 7차 교육과정 이후에 초점을 맞추고 있으며, 초창기 교육 과정에서의 중국어 교육 도입과 발전 과정에 관한 연구는 극히 드물다. 이에 본고는 1945년 해방 이후 “신조선의 조선인을 위한 교육방침” 발 표에서부터 1953년 휴전 협정 이후 본격적으로 정립되기 시작한 “제1차 교육과정”을 두루 살피며 현대 중국어 교육의 도입 배경과 발전 과정을 분석하였다. 이를 통해, 현대 교육과정에서의 중국어 교육이 가지는 의미 와 필요성을 다시금 상기하고 변화하는 시대에 대응할 수 있는 중국어 교육의 발전 방향에 대해 논의하였다. 제2외국어 교육은 단순히 선택과 목, 교양과목의 의미를 넘어 심화되어가는 세계화와 정보화 사회 속에서 소통과 교류를 위한 핵심 역량 함양의 근간이라 할 수 있다. 본 논문이 중국어 교육을 비롯한 국내 외국어 교육 발전에 작게나마 기여할 수 있 길 바란다.
This study investigated phenolic compounds and radical scavenging activities of rapeseed plants according to cultivar and growth stage. For 1st, 2nd, and 3rd harvested rapeseed plants, total polyphenol contents were 12.56~15.85, 10.28~13.17, and 9.94~16.01 mg gallic acid equivalents/g sample, respectively; total flavonoid contents were 9.86~11.05, 10.41~13.06, and 8.18~16.64 mg catechin equivalents/g sample, respectively; total chlorophyll contents were 17.26~21.66, 19.31~24.95, and 22.16~38.39 mg/g sample, respectively; and total glucosinolates contents were 31.13~46.22, 28.51~34.72, and 22.18~30.58 mg SE/g sample, respectively. DPPH and ABTS radical scavenging activities of rapeseed plants were 3.26~5.91 and 10.69~17.17 mg trolox equivalents/g sample, respectively. FRAP activities of 1st, 2nd, and 3rd harvested rapeseed plants were 142.88~63.93, 37.97~61.24, and 32.93~52.36 mM/g sample, respectively. Phenolic compounds and radical scavenging activities of rapeseed plants were found to be high in Halla, Yuryeo, and Yeongsan cultivars. Overall, phenolic compounds and radical scavenging activities of rapeseed plants tended to decrease as the harvest time was delayed. These results indicate that more research on functional ingredients and physiological activities of rapeseed plants is needed to diversify their fields of use.
This study examined the quality characteristics and antioxidant properties of sword bean tea available in domestic markets. Each product of sword bean tea had distinct appearance characteristics. The color, pH, brownness, and turbidity of the tea varied significantly across different products, with tea bags showing higher levels of brownness and turbidity. The total polyphenol content of hot water extraction ranged from 165.13 to 517.69 mg gallic acid equivalents (GAE)/100 g sample for pod tea, 999.36 to 2,054.74 mg GAE/100 g sample for tea bag tea, and 74.62 to 275.00 mg GAE/100 g sample for grain tea, respectively. Similarly, the total flavonoid content, measured in terms of catechin equivalents (CE), ranged from 39.51 to 65.00 mg CE/100 g sample for pod tea, 86.57 to 253.63 mg CE/100 g sample for tea bag tea, and 32.94 to 38.63 mg CE/100 g sample for grain tea, for hot water extraction. The DPPH and ABTS radical scavenging activities of pod tea were 95.68 to 276.19 mg TE/100 g sample and 270.87 to 804.21 mg trolox equivalents/100 g sample, respectively, for hot water extraction. These results suggest the need to establish quality standards to ensure consistent quality of sword bean tea.
중국은 예로부터 우리나라와 정치, 경제, 문화적으로 가장 가까운 나라였으며, 이 에 따라 중국어는 가장 중요한 외국어로 인식되었다. 우리나라에서는 고려시대에는 통문관(通文館), 조선시대 사역원(司譯院)을 통해 중국어가 교육되었고 四書나 直 解小學과 같은 중국의 경전이나 老乞大, 朴通事와 같은 회화서를 사용했다. 조 선 중기, 왜란과 호란을 겪으면서 실질적인 의사소통에 필요한 교재가 필요함을 깨 달으며 여러 회화서의 개수본(改修本) 뿐만 아니라, 譯語類解와 같은 유해류(類解 類), 즉 분류어휘집도 편찬되었는데 이는 다양하고 풍부한 어휘 학습을 도와 정확한 의사소통에 기여하였다. 이후 19세기에 들어서는 민간에서 중국어 학습 수요가 증가 하여 민간인 저자에 의해 華語類抄, 漢語抄, 華語, 漢談官話와 같은 유해류 서적이 편찬되었다. 이들은 19세기에서 20세기에 이르는 근현대시기 한국과 중국 두나라의 언어사를 조명할 수 있다는 점에서 중요한 의의를 갖는다. 漢談官話는 1902년 필사, 편찬된 것으로 추정되며, 저자는 미상이다. 18개의 부 류(部類)로 나누어 총 613개의 어휘를 실었다. 譯語類解나 華語類抄처럼 천문(天 文)으로 시작하지 않고 인사‧관직 관련 어휘로 시작하고 있으며, ‘一字部’, ‘不字部’, ‘長語類’와 같이 일상생활에서 주로 쓰이는 구어체의 어휘, 어구, 문장 표현을 실어 실용성을 높였다. 어휘 부류 및 뜻풀이의 형식과 내용에서는 기존 유해서의 전통을 계승하면서도, 혁신을 꾀하였다. 각 부에 수록된 어휘는 의미의 상관관계에 따라 연 관성이 있는 표제어끼리 가깝게 배열되었다. 또한, 사용자가 비교적 쉽게 이해할 수 있는 언문(諺文) 대역어(즉 당시의 한국어)와 한자 및 한문을 이용하여 뜻풀이했다. 譯語類解나 華語類抄와 공통적으로 수록된 어휘 비율이 매우 낮아 漢談官話의 저자가 매우 독자적인 시각에서 어휘를 수집, 분류했음을 알 수 있다. 漢談官話의 주음(注音) 측면에서 살펴보면, 見組 성모가 일부 구개음화 되기 전 의 형태인 ‘ㄱ’, ‘ㅋ’으로 기록된 것과 日母가 영성모로 기록된 것은 동북 방언의 영 향을 받은 부분이다. 그러나 來母를 ‘ㄴ’으로 주음 한 것과 같이 당시 한국 한자음을 학습하는 사람들이 범하는 오류에 따라 주음하고, 端組를 ‘ㅈ’혹은 ‘ㅊ’과 같이 한국 한자음에서의 구개음화 현상에 따라 주음하며, ‘兒’을 ‘라’로 기록한 것은 저자의 중 국어 음운학적 지식의 한계에 기인한 것이자, 이 책의 한계를 보여주는 부분이다. 그 러나 漢談官話는 체제, 형식, 어휘, 뜻풀이 면에서 볼 때 기존 유해류 서적과는 뚜 렷한 차별성을 보이는 혁신적인 성격의 유해류 서적이라고 할 수 있으며, 근현대 한 중 양국의 언어사 연구에 있어서 매우 중요한 가치를 지닌다.
In this study, quality properties of rapeseed oil by different roasting temperatures (140, 160, 180, and 200℃) were investigated. Roasted-pressed oil (RPO) showed a decrease in lightness and an increase in redness and yellowness with an increase in temperature compared to cold-pressed oil (CPO). In addition, the β-carotene and tocopherol content also increased in RPO as the roasting temperature increased. The tocopherol content increased by 18~20% in RPO at 200℃ compared to CPO. This increase in bioactive components led to improved radical scavenging activity dependent on roasting temperature, and RPO at 200°C showed a 2.7-fold improvement compared to CPO. Finally, it was observed that higher roasting temperatures resulted in an extended oxidation induction period, increasing by up to 3.3 times. In conclusion, roasting is an effective method for enhancing the oil functionality of domestic rapeseed varieties. This study provides basic data for producing high-quality oil.
This study investigated the antioxidant characteristics of sweet potato according to different plant parts and drying methods. The sweet potato plant parts were divided into root tubers, stems, stalks, leaves, and tips, and the drying methods were freeze-drying and hot air drying. Total polyphenol and flavonoid contents and radical scavenging activity of the sweet potato plant parts were significantly different depending on the plant parts and drying methods. The total polyphenol content of freeze-dried sweet potato leaves and tips were 52.76 and 46.19 mg chlorogenic acid equivalents/g sample, and the total flavonoid contents were 222.47 and 214.12 mg quercetin equivalents/g sample, respectively, and decreased with hot air drying. DPPH radical scavenging activity was higher in freeze-drying than hot air drying and was significantly different depending on the plant parts. The ABTS radical scavenging activity of freeze-dried sweet potato leaves and tips were 43.48 and 44.68 mg Trolox equivalents/g sample, respectively, and decreased with hot air drying. Therefore, additional studies on the functionality of using by-products from sweet potato cultivation are needed.
The consumption of ready-to-eat side dishes is rapidly growing in South Korea. These foods are particularly vulnerable to microbiological contamination as they are often cooked without any treatment, such as heating or stored at room temperature after cooking. Hence, in 2022, we analyzed the ready-to-eat side dishes sold in Gyeongsangnam-do, South Korea for microbiological contamination. We collected 100 samples from supermarkets in 7 cities, and then examined them for presence of food-borne pathogens and sanitary indicator bacteria. In the analysis of the food-borne pathogens, Bacillus cereus and Clostridium perfringens were isolated from 51 samples (51.0%) and 3 samples (3.0%), respectively. However, both quantitatively met the Korean Food Standards Codex. Genes of five different enterotoxins and one emetic toxin were analyzed from the 51 isolated B. cereus strains. We detected enterotoxin entFM (100.0%), nheA (94.1%), hblC (58.8%), cytK (56.9%), and bceT (41.2%) in 51 isolates, and emetic toxin gene, CER, in only one (2.0%) isolate. We did not detect C. perfringens toxin gene (cpe) that causes food poisoning in any one of the three C. perfringens isolates. In the case of sanitary indicator bacteria, Kimchi had the highest levels of total aerobic bacteria and coliforms, followed by Saengchae, Jeotgal, Jeolim, Namul, and Jorim, respectively. We counted total aerobic bacteria at two different storage temperatures (4oC and 20oC) to determine the effect of storage temperature. When stored at 20oC, total aerobic bacteria count increased in most of the ready-to-eat side dishes, except for Jeotgal. This result conclusively shows the need for refrigerating the ready-to-eat side dishes after purchase. Further research is needed to assess the risk and safety of the ready-to-eat side dishes available in the market and determine appropriate safety management practices.
FT-IR, GC/MS, and ATR-FT-IR analyses were performed to confirm the physicochemical characteristics of saw palmetto fruit (SPF) extract. FT-IR analysis of the standard product showed that the band corresponding to the carbonyl bond of free fatty acid was stronger than the band of acyl-glyceride. Sample E was identified as having the same trend as the standard sample. Fatty acid composition analysis revealed that the main fatty acids in the standard sample were lauric acid and oleic acid. The content of lauric acid ranged from approximately 30% to 38% in samples B, C, D, and E, while the content of oleic acid ranged from approximately 29% to 34%. The GC/MS analysis confirmed that the standard SPF extract consisted of fatty acids and fatty acid ethyl esters. Sample E demonstrated a similar pattern to the standard samples in terms of oleic acid, lauric acid, and fatty acid esters. ATR-FT-IR analysis indicated that only sample E was predicted to contain 100% saw palmetto extract. Therefore, these study findings can be considered fundamental data for analyzing the physicochemical characteristics of the composition of SPF extract.
The quality and antioxidant characteristics of apios (Apios americana Medikus) according to different harvest periods and steaming treatment were investigated. The quality and antioxidant characteristics of apios were significantly different depending on harvest periods. Total starch contents was higher in 1st harvesting period as 62.32 g/100 g than other harvesting period. The water binding capacity and water solubility index was higher in 1st harvesting period as 228.65 and 11.29% than other harvesting period. The sucrose and total free sugar contents were 3.64~8.67 and 4.49~9.54 g/100 g, respectively. Total polyphenol and flavonoid contents of apios was the highest 2nd and 4th harvesting period at 4.21 mg GAE/g and 611.11 μg CE/g, respectively. DPPH radical scavenging activity was higher in 1st harvesting period as 84.96 mg TE/100 g than other harvesting period, and decreased as the harvest periods were delayed. ABTS radical scavenging activity and ferric-reducing antioxidant power were 43.81~47.89 mg TE/g and 231.20~264.07 mM/100 g, and increased to 50.58~51.44 mg TE/g and 342.55~384.29 mM/100 g after heat treatment. As a result, it is thought that studies on change of quality and physicochemical characteristics according to cultivation characteristics should be preceded for cultivation stability of apios.
본 연구는 발효노니 다당체 추출물(Vitalbos)을 건강기능 식품 소재로 활용하기 위해 DAA, 총당 함량, 단당류 3종 (galacturonic acid, glucose 및 galactose)을 지표성분으로 설정하고, 지표성분에 대한 효과적인 분석법 설정 및 검 증을 위해 수행되었다. 기존에 보고된 분석법 검증 방법 을 수정하여 특이성, 직선성, 정밀성, 정확성, 검출한계 (LOD) 및 정량한계(LOQ)를 고성능 액체크로마토그래피와 페놀-황산법을 이용하여 측정하였다. 그 결과 DAA 및 단 당류 3종의 표준용액과 Vitalbos의 머무름 시간이 일치하 였으며 스펙트럼 또한 동일하여 분석법의 특이성을 확인 하였다. 지표성분의 검량선 상관계수(R2)는 0.9995-0.9998 범위로 0.99 이상의 우수한 직선성을 나타냈다. Intra-day 및 inter-day 정밀도는 0.14-3.01%의 범위로 5% 미만의 우 수한 정밀도를 나타냈고 회수율은 95.13-105.59% 범위에 서 우수한 정확도를 보였다. DAA 분석의 LOD와 LOQ는 각각 0.39 μg/mL 및 1.18 μg/mL이었으며 총당 함량의 LOD 및 LOQ는 각각 0.84 μg/mL 및 2.55 μg/mL로 측정 되었다. 단당류 3종에 대한 LOD는 0.48-0.81 μg/mL의 범 위였으며, LOQ는 1.45-2.44 μg/mL 범위에서 정량분석이 가능한 것으로 나타났다. 분석법 검증 결과, 특이성, 직선 성, 정밀성 및 정확성 모두 우수한 분석법임을 검증하였 으며, LOD와 LOQ 또한 Vitalbos 분석에 적합하였음을 확 인하였다. 검증된 분석법을 이용하여 Vitalbos의 지표 성분 함량을 측정하였을 때, DAA, 총당 함량, galacturonic acid, glucose 및 galactose의 함량은 각각 2.31±0.06 mg/dry weight g, 475.92±5.95 mg/dry weight g, 72.83±1.05 mg/dry weight g, 71.63±2.44 mg/dry weight g 및 67.30±2.31 mg/dry weight g으로 측정되었다. 본 연구에서 검증된 분석법을 사용했을 때 Vitalbos의 지표성분 3종에 대하여 우수한 재현성으로 정 량분석이 가능하였으며, 건강기능식품 소재로의 품질관리에 기여할 수 있을 것으로 판단된다.
예로부터 우리나라는 중국과 정치, 경제, 문화적으로 가장 가까운 관계에 있었으며, 중국어는 늘 중요한 외국어로 인정받고 있었다. 한글 창제 이후 간행된 조선 시대 중국어 역학서는 당시 언어 특징과 생활, 문화상에 대한 풍부한 정보를 담고 있는 寶庫라 할 수 있다. 이들에 대한 연구성과는 상당히 축적되어 있으나 아직도 연구 방법과 연구 환경에 있어서 매우 초보적인 단계에 머물러있어, 스캔한 원본 이미지 혹은 중국어 원문이나 언해문 등의 불완전한 2차 가공물 정도만 웹사이트 상에서 열 람할 수 있다. 이에, 본 연구는 조선 시대 중국어 역학서인 『老乞大諺解』, 『朴通事諺 解』, 『譯語類解』, 『五倫全備諺解』, 『譯語類解補』, 『朴通事新釋諺解』, 『重刊老乞大諺解 』, 『華音啓蒙諺解』, 『華語類抄』와 중국어 원문만으로 이루어진 『老乞大』, 『朴通事新 釋』의 총 11종 역학서 및 동일한 서명의 다른 판본 총 31개의 서적을 대상으로 규장 각한국학연구원 웹사이트에서 아직 제공하지 않는 원문과 번역문에 대한 데이터를 TSV(Tab Separated Values)와 XML(eXtensible Markup Language) 형식으로 구축하였다. 본 연구는 조선 시대 중국어 역학서에 대한 원문과 번역문을 총망라한 최초 의 연구성과이다. 이를 통해 대중에게 국학 자료에 대한 관심을 제고하고, 연구자들 에게 더 나은 연구 환경을 제공하며, 한국어, 중국어학 및 문화사 등의 교육 및 연구 에 활용할 수 있을 것이다. 그리고 여러 관련 데이터베이스를 연계하여 동아시아 지 역의 교류에 대한 사회사적, 문화사적 연구의 발판이 되어줄 것이다.
본 연구는 지역별로 수집한 유채 균핵병 균주에 대해 등록 된 3종의 약제를 사용하여 저항성 검정을 실시하였고, 저항성 발생 가능성이 있는 약제의 작용 기작과 관련한 유전자를 분석하여 변이 유무를 확인하였다. 1. Carbendazim-diethofencarb 약제배지의 경우, 0.1 ppm 농도에서 균사 생장 억제율은 13.3~41.9% 범위로 나타났으며, 1 ppm 이상의 농도에서는 모든 균주에서 96.1% 억제율을 보여 균주의 저항성이 확인되지 않았다. 2. Fludioxonil 약제배지는 0.1 ppm 농도에서 균사의 생장이 94.2% 이상 억제되었으며, 1 ppm 농도에서부터 100%의 억제 율을 보여 가장 약제 효과가 우수한 것으로 나타나 수집한 모든 균주에서 약제의 감수성을 확인하였다. 3. Boscalid 약제배지는 앞선 2종의 약제에 비해 균주의 균사 생장 억제가 뚜렷하지 않았다. 특히 10 ppm 농도에서 무안 수집 균주는 93.9%, 나주 수집 균주는 79.3%로 지역 간 차이가 있었으며, 1000 ppm의 높은 약제 농도에서도 균사의 생장을 100%까지 억제하지 못해 약제에 대한 균주의 저항성 발생 가능성을 추측하였다. 4. 3종의 시험 약제 농도별 균핵병 균주의 균사 생장을 50% 억제하는 농도(EC50)를 분석한 결과, Fludioxonil, Carbendazim-diethofencarb, Boscalid 약제순이었으며, 그 값은 각각 0.06, 0.16, 0.43 ppm으로 나타났다. 5. 또한, 3종의 시험 약제 농도별 발생한 균주의 균핵 형성 능력은 1 ppm 농도에서 Carbendazim-diethofencarb는 5.6개, Fludioxonil은 0개로 나타난 반면, Boscalid는 최대 11.3개의 균핵이 형성되어 차이를 확인할 수 있었다. 6. Boscalid 약제에 대한 균주의 저항성을 확인하기 위해 해당 약제의 작용 기작인 SDHI와 관련된 유전자 SdhB를 염기 서열 분석하였다. 염기서열 분석 결과 무안 및 부산에서 수집 한 균주의 경우 SdhB 표준 염기서열과 일치하여 감수성이었으나, 나주, 당진, 제주, 영암에서 수집한 균주는 32번째 염기 가 C→T로 치환되어 GCA(Alanine)→GTA(Valine) 점 돌연변이를 확인하였다.
Graphene has attracted the interest of many researchers due to various its advantages such as high mobility, high transparency, and strong mechanical strength. However, large-area graphene is grown at high temperatures of about 1,000 °C and must be transferred to various substrates for various applications. As a result, transferred graphene shows many defects such as wrinkles/ripples and cracks that happen during the transfer process. In this study, we address transfer-free, large-scale, and high-quality monolayer graphene. Monolayer graphene was grown at low temperatures on Ti (10nm)-buffered Si (001) and PET substrates via plasma-assisted thermal chemical vapor deposition (PATCVD). The graphene area is small at low mTorr range of operating pressure, while 4 × 4 cm2 scale graphene is grown at high working pressures from 1.5 to 1.8 Torr. Four-inch wafer scale graphene growth is achieved at growth conditions of 1.8 Torr working pressure and 150 °C growth temperature. The monolayer graphene that is grown directly on the Ti-buffer layer reveals a transparency of 97.4 % at a wavelength of 550 nm, a carrier mobility of about 7,000 cm2/V×s, and a sheet resistance of 98 W/□. Transfer-free, large-scale, high-quality monolayer graphene can be applied to flexible and stretchable electronic devices.
1. 본 연구는 고구마의 큐어링 처리 및 저장기간에 따른 품종별 저장성 차이를 조사하여 품종별 적정 저장 조건을 설정하고자 수행하였다. 수확된 고구마는 온도 32±1℃, 상대습도 92±3% 조건에서 3일간 큐어링 처리를 실시하였고 대조구와 함께 13±℃의 저장고에 30주간 저장하였다. 2. 저장 기간에 따른 부패율 및 감모율은 품종별로 큐어링 처리 여부에 따라 다른 양상을 보였으며 대부분 품종에서 큐어링 처리구의 부패율과 감모율이 낮게 나타났다. 품종별로는 ‘호감미’, ‘풍원미’, ‘신건미’, ‘주황미’가 장기저장을 위해서 큐어링 처리가 필요한 품종으로 나타났으며, ‘다호미’, ‘연자미’ 품종은 큐어링 처리 여부에 따른 유의한 차이가 없었다. 3. 큐어링 처리 여부에 따른 부패율 차이가 없었던 ‘다호미’, ‘연자미’를 제외한 나머지 품종은 감모율 조사에서도 큐어링 처리가 장기 저장에 더 유리한 것으로 조사되었다. 4. ‘호감미’ 품종의 경우 저장기간별 부패율 및 감모율을 예측하고 조수입을 계산하였을 때 큐어링 처리 시에는 조수입이 증가하였으나 큐어링 무처리 시에는 저장기간이 길어질수록 조수입이 감소하였다. 5. 따라서 이러한 품종별 저장성 차이를 고려하여 각 품종에 맞는 수확 후 관리 및 적정 출하시기를 예측하는 것이 고구마 저장성 증대 및 농가 소득 향상에 유용하게 적용될 수 있을 것으로 판단된다.
This study was carried out to obtain the basic quality characteristics, like moisture contents, hunter color value, total polyphenol, starch, amylose, and ash contents and pasting characteristics of sweet potato cultivars according to storage periods. Moisture contents of all the varieties decreased with long storage period, and were lower in dry type than tender and moist type sweet potato. Lightness(L value) of sweet potato flesh was decreased in Shinyulmi, Daeyumi, Shinhwangmi but other seven cultivars showed increasing trend. Redness(a value) was increased in Sinyulmi, Sinhwangmi, Sinjami and yellowness (b value) increased in Yeonjami only. The total polyphenol contents increased in Dahomi, Sinjami up to 4 months of storage and all other varieties showed decrease during storage period. The starch contents also decreased with storage period. The amylose contents showed different by the cultivars. The ash contents in all varieties ranged from 1.1 to 1.7%, and there was no difference among varieties and storage periods. There was no change in pasting temperature during storage periods. Peak viscosity, through viscosity, breakdown and final viscosity were different according to storage periods and cultivars. But setback tended to increase in all cultivars.
Sweet potato [Ipomoea batatas (L.) lam] plant is known to have the relatively tolerance soil moisture deficit compared to other upland crops. However, recently, it has been causing plant growth inhibition and decrease storage quality due to the drought during the growing season of sweetpotato in Korea. The response of root elongation, leaf and shoot growth of sweet potato plantlets, cultivated under different water potential conditions were observed. Six varieties, such as yellow fleshed (Jinhongmi), dark-yellow fleshed (Daeyumi), dark-orange fleshed (Juhwangmi), light-orange fleshed (Dahomi, Pungwonmi), and purple fleshed (Sinjami) were used in this experiment. Using the follow water osmotic potential (WOP) levels were 0 (control), -0.05, -0.1, -0.2, -0.3, -0.4, -0.5 MPa by polyethylene glycol (PEG). In in vitro culture condition, ‘Jinhongmi’ has been inhibited rooting number and number of leaves less than 2, although slightly low WOP of–0.05 and –0.1 MPa, and at –0.2 MPa. shoot was not growing. ‘Daeyumi’, Dahomi, and Juwhangmi’ produced 2 roots as a low WOP of –0.3 MPa. and at –0.2 MPa., it appeared 2 or 3 leaves. ‘Pungwonmi’ produced similar to root number 3.9 at –0.1 MPa compared to control, but root weight decreased 75% at - 0.1 MPa more than control. Root did not grow at – 0.2 MPa for ‘Sinjami’. In nursery bed culture condition, roots fresh weight, number of leaves, and shoot length were inhibited according to the decreases of water osmotic potential. In the case of leaf area, ‘Jinhongmi’ and ‘Daeyumi’ was a significantly difference to 8.4, 22.6 cm3 at –0.2 MPa compared to control, respectively. No difference were obsered for ‘Dahomi’ at -0.1 and –0.2 MPa. ‘Pungwonmi’ was decreased 86% at -0.1 MPa compared to the control. ‘Juhwangmi’ and ‘Sinjami’ was a significantly difference to 15.5, 3.6 cm3 at –0.1 MPa compared to control of 22.9, 16.8 cm3, respectively.
The most common method of vegetative propagation of virus free plantlets is the use of shoots meristem culture in solid medium culture. This study was to investigate the effect on liquid medium culture for the growth of virus-free sweetpotato plantlets. Single-nodes derived from meristem culture of sweetpotato was examined in this experiment and three sweetpotato varieties ‘Singeonmi’, ‘Sinhwangmi’, and ‘Sinjami’ was used. The growth of plnatlets was greater in liquid medium culture than that of solid medium culture after longer incubation in 3 varieties. The total fresh weight of 5 week old plantlets after planting in solid culture were 2.17 g (‘Singeonmi’), 2.49 g (‘Sinhwangmi’), and 2.18 g (‘Sinjami’), but the fresh weight in liquid medium culture was 3.87, 3.88, and 3.35 g, respectively. Leaf number of ‘Singeonmi’ and ‘Sinjami’ plantlets after 5 weeks of liquid medium culture was 21.1 and 22.6, respectively and liquid medium culture showed 3 and 6.2 more leaf number than that of solid medium culture. Plant height of ‘Sinhwangmi’ and ‘Sinjami’ plantlets after 3 weeks of liquid medium culture was 4.1 cm and 3.4 cm, respectively, and liquid medium culture showed 1.1 cm longer stem length than solid medium. Overall, liquid medium culture of sweetpotato plantlets was more effective than solid medium in terms of leaf and stem growth.
The effect of transplanting and harvesting dates on growth, yield, and quality of sweetpotato varieties was studied. Three sweetpotato varieties, Yulmi, Singeonmi, and Dahomi, were transplanted on 23 Apr., 21 May, 5 June, 15 June, 25 June, 5 July, 15 July, and 25 July. Fresh vine weight and marketable storage root yield of the three varieties were the highest in transplanting plots on 23 April and 21 May, respectively, and those tended to decrease when transplanting dates were late after May. GDD (Growing Degree Days) and cumulative radiation seemed to be related to marketable storage root yield. Number of marketable storage root per plant, average weight of marketable storage root, and marketable storage root yield were significantly different according to transplanting dates. Marketable storage root yield showed significantly positive correlations with fresh vine weight, number of marketable storage roots, and average weight of marketable storage roots. Hardness and dry matter content of storage root showed significantly positive correlations with starch content and decreased with late transplanting dates in Yulmi and Singeonmi varieties. Pasting temperature showed significantly positive correlations with soluble solid content, dry matter content, and amylose content, but it showed significantly negative correlations with breakdown. Setback was significantly different among varieties, but it was not significantly different in transplanting dates.
Understanding of a carbon storage in a regional scale ecosystem is a very important data for predicting change of global carbon cycle. Therefore, the real data collected in the various ecosystems are a very useful for enhancing accuracy of model prediction. We tried to estimate total accumulated ecosystem carbon in Deogyusan National Park (DNP) with naturally well preserved ecosystem. In DNP, vegetations were classified to four main communities with Quercus mongolica community (12,636.9 ha, 54.8%), Quercus variabilis community (2,987.0 ha, 13.0%), Pinus densiflora community (5,758.0 ha, 25.0%), and Quercus serrata community (402.9 ha,1.7%). Biomass and soil carbons were estimated by the biomass allometric equations based on the DBH and carbon contents of litter and soil (0~30 cm) layers collected in 3 plots (30 cm×30 cm) in each community. The biomass and soil carbons were shown as high value as 1,759,000 tC and 7,776,000 tC, respectively, in Quercus mongolia community in DNP area. In Quercus mongolica, Quercus variabilis, Quercus serrata, Pinus densiflora communities, the accumulated ecosystem carbon were shown 9,536,000 tC, 1,405,000 tC, 147,000 tC, 346,000 tC, respectively. Also, the total ecosystem carbon was estimated with 11,434,000 tC in DNP.