This study was carried out to determine the sprouting period of early and mid-season varieties, which includes ‘Atlantic’, ‘Chubaek’, and ‘Superior’, during the summer storage period in a semi-underground warehouse without cooling system. And also it was investigated the effect of chlorpropham [Propan-2-yl N-(3-chlorophenyl)carbamate, CIPC] treatment on the sprouting inhibition for the varieties. This study was conducted to figure out a sprout inhibitory effect when CIPC was applied to 1kg of the potato tubers at concentrations of 10 mg and 20 mg which are lower than the treatment concentrations of ca 30 mg prescribed by the positive list system (PLS). The internal temperature of the warehouse used in this experiment was lowered by 5°C or more than the outside temperature. The difference between the lowest and highest temperature during the experiment throughout the day was 5°C. It showed the effect of reducing to 1/2 of the difference in outdoor temperature. As for the sprouting of potatoes, the extremely early variety ‘Chubaek’ sprouts appeared at the 6th week of storage of control and it was the fastest sprouting potato among the control groups of the varieties. Sprouting began to appear in the Superior at the 6th week of storage, while the ‘Atlantic’ sprouted at the 8th week of storage. The appearance of sprouts was suppressed in all treatment groups of ‘Atlantic’ and ‘Superior’ varieties in CIPC treatments. Sprouts were observed in all treatment groups of ‘Chubaek’ after the 7th week, but the elongations of the sprouts in tubers were completely inhibited until the 8th week of storage. ‘Atlantic’ and ‘Superior’ seemed to have a sprouting inhibitory effect even with a low CIPC concentration of 10 mg·kg-1, with the exception of extremely early variety ‘Chubaek’ that breaks out of the dormancy quickly. Although weight loss occurred continuously during storage, it was minor loss of 0.7-1.6%. There was no consistent trend for changes of the loss in the varieties and CIPC treatments. Most common pathological disorder was the dry rot during the experiment, but only few were affected. The use of the tubers treated at 18°C and 90% RH for 10 days and the rack of refrigeration system which lead to lack of convection seemed to have suppressed the spread of pathogens.

본 연구는 저장 온도를 달리하여 높은 상대습도의 환경에서 건조 감자를 저장하였을 때 발생하는 품질변화를 관찰하였다. 저장기간 및 건조온도가 증가함에 따라 L* value 는 감소하였고, a* 및 b* value는 증가하는 경향을 나타내었다. 수분활성도는 높은 습도 조건으로 인해 10일차부터 급격히 증가하였으며, 환원형 비타민 C 함량은 급격히 감소하는 경향을 나타내었다. pH 값은 저장기간 동안 완만하게 감소하였으며 40oC에서 저장했을 때 큰 폭으로 감소하였다. 저장기간 동안 대장균군은 검출되지 않았으며, 일반 세균 수는 저장 온도가 증가함에 따라 많이 검출되었다. 전체적으로 20oC와 30oC에서 저장한 시료 간의 차이는 크지 않았으나, 40oC에서 저장한 시료의 경우 큰 품질변화를 나타내었고, 밀봉된 상태로 저장한 대조구의 경우 품질변화가 적게 나타나는 것을 확인할 수 있었다. 따라서 본 연구결과를 종합해 볼 때, 밀봉하여 산소와 수분을 차단한 상태로 저장하는 것이 제품 고유의 특성을 유지하는데 가장 효과적이며, 높은 습도의 환경일 경우 낮은 온도로 저장하는 것이 품질 변화를 지연시키는데 도움이 될 것으로 판단된다.

The changes in DNA damage were investigated during storage after irradiation. Potato, garlic were irradiated at 0.05, 0.07, 0.1 and 0.15 kGy and stored for 3 months. Ginger was irradiated at 0.01, 0.02, 0.03, 0.04 and 0.05 kGy and stored for 1 month. The comet assay was applied to the sample immediately after irradiation and at the end of storage. Samples were isolated, grounded and the suspended cells were embedded in an agarose layer. After lysis of the cells, they were electrophoresed for 1 min. and then stained. DNA fragmentation in seeds caused by irradiation was quantified as tail length and tail moment (tail length ×% DNA in tail) by comet image analyzing system. Right after irradiation, the differences in tail length between unirradiated and irradiated samples were significant(p〈0.05) in potato, garlic and ginger. With increasing the irradiation doses, statistically significant longer extension of the DNA from the nucleus toward anode was observed. The results represented as tail moment showed similar tendency to those of tail length. Similarly in the stored samples, even 1 or 3 months after irradiation, all the irradiated samples significantly showed longer tail length than the unirradiated controls. These results indicate that the comet assay could be one of the simple methods of detecting irradiated samples. Moreover, the method could detect DNA damage even after 1 or 3 months after irradiation.

Three potato cultivars were prepared as slices and stored for 4 weeks at 5℃. Changes in Vitamin C content and other quality factors, such as color, pH, soluble solid and protein content were determined. Vitamin C content and L value decreased in three potato cultivars. Initial Vitamin C contents of three potato cultivars varied from 49.27 mg% in Sumi to 56.40 mg% in Namjak. Changes in L value showed that the tendency of browning in Daejima was slower than Sumi and Namjak. Changes in pH were small. Soluble solids and protein content increased and varied by cultivar. From the correlation analysis, correlation between browning degree and Vitamin C content was low in three potato cultivars.

Three potato cultivars, Sumi,Daejima and Namjak, were prepared as slices. They were dipped in distilled water for 20 seconds. The potato slices were packed in polyethylene bags and stored at 5℃. Browning degree, total phenol and chlorogenic acid contents and polyphenol oxidase (PPO) activity were measured. And the correlation analysis of browning parameters were conducted. The results were as follows. There were increase in browning degree, phenolic content and PPO activity during cold storage of potato slices with different cultivars. Among three cultivars, Sumi showed the highest browning degree, phenolic content and PPO activity and also showed the highest % increse of browning and PPO activity during cold storage. On the contrary, Daejima was the lowest. But Daejima showed the highest % increase in phenolic contents during cold storage. With Sumi, browning degree was significantly correlated with PPO activity and phenolic contents (p〈0.05). With Daejima and Namjak, a significant correlation was found between browning degree and PPO activity (p〈0.05). From the above results, enzymatic browning reactions of potato slices and factors affecting them were dependent on cultivar. Among the tested three cultivars, Daejima showed the lowest browning degree during cold storage and thus seems to be desirable for minimal processing.

Potato greening determines the shelf life and affects the marketability of this tuber. Various stresses during handling and storage interact to affect the tuber’s physiological status and can affect the rate of greening. This study investigated the effects of storage temperature on tuber greening and shelf life in unwashed and washed potatoes of the cultivar Superior. Physiological and biochemical changes were examined during 15 days at room temperature (23±2°C) under cool-white fluorescent light after storage for 1 month at different temperatures (4°C, 20°C). Hunter a values were negative (-) for washed potatoes after 3 days (-0.8) and 15 days (-2.5) at room temperature following 1 month of storage at 4°C while positive (+) values were observed for unwashed potatoes after 15 days at room temperature. The Hunter ΔE values of washed potatoes previously stored at 4°C for 1 month increased after 3 days at room temperature compared with those of unwashed potatoes. The total chlorophyll content of washed potatoes was higher than that of unwashed potatoes. The highest correlation was observed between the Hunter ΔE value and Hunter a value (-0.93506), while a positive correlation coefficient (0.89806) was observed between greening criteria and Hunter ΔE value by using colorimetry. We conclude, therefore, that there is a biosynthetic link between temperature-induced chlorophyll accumulation and tuber greening in storage.

Sweet potato has low regeneration capacity, which is a serious obstacle for the fruitful production of transgenic plants. Simple and rapid regeneration method from storage root explants of purple sweet potato (Ipomoea batatas L.) was investigated. The embryogenic callus was observed from 4 cultivars and its highest rate was induced at 1 μM 2,4-D after 5 weeks of culture. Result revealed that a low concentration of 2,4-D and low light intensity was important factors for embryogenic callus formation. After subculture on medium with 5 μM ABA for 4 days, subsequently, occurred the regeneration of shoots within 4 weeks when these embryogenic callus was transferred onto the MS hormone free medium. Regenerated shoots were developed into platelets, and grown normal plants in the greenhouse. We developed a simple and quickly protocol to regenerate plantlets in storage root explants of purple sweet potato. This regeneration system will facilitate tissue culture and gene transfer research of purple sweet potato.

식물체에 대한 에틸렌의 다양한 반응에도 불구하고, 감자 가공 산업을 중심으로 에틸렌의 맹아억제제로서의 가능성에 관해서만 주로 검토되어 왔다. 그러나 본 연구에서는 씨감자에 에틸렌을 처 리하여 생리적 서령 조절제로서의 가능성을 확인코자 하였다. 국내 에서 가장 많이 재배되고 있는 ‘수미’ 감자를 대상으로 처리방법, 처리농도 등을 달리하여 저장 중 에틸렌 가스를 처리 한 후 휴면타파 및 맹아의 생장에 미치는 영향을 조사하였다. 에틸렌이 처리된 감자 괴경은 처리 후 1~2일에 급격히 호흡율이 상승해 감자 괴경의 에틸렌에 대한 민감한 반응을 확인할 수 있었다. 3일간의 단기간 에 틸렌 처리는 감자 괴경의 휴면을 약간 타파시키는 결과를 보였으 나, 2 μL/L 농도의 연속 처리구에서는 오히려 저장 40일까지 전혀 맹아가 되지 않아 뚜렷한 맹아억제 효과를 보였다. 에텔린 농도와 처리기간을 달리한 연속처리 시험에서는 2 또는 4μL/L 농도 처리 구 공히 뚜렷한 맹아억제 효과를 다시 확인할 수 있었고, 짧고 많은 수의 맹아가 발생되는 현상을 발견할 수 있었다. 이렇게 에틸렌이 처리된 씨감자를 온실 내 포트에 파종하여 재배한 결과 출현속도에 서는 큰 차이가 없었으나 에틸렌 처리에 의해 식물체당 줄기수와 복지수가 증가되었다. 수량성에서는 뚜렷한 경향 없이 처리 간 약 간의 차이를 보였으나 식물체당 괴경수는 에틸렌 처리에 의해 현저 히 증가되는 결과를 확인할 수 있었다. 이상의 결과를 종합해 볼 때, 저장중 씨감자를 대상으로 한 에틸렌 가스 처리, 특히 2~4μL/L 농 도범위에서 씨감자의 생리적 서령을 조절하는 유용한 수단으로 활 용될 수 있을 것으로 기대된다.

PGA 함량 정보가 없는 유전자원을 활용한 다양한 용도의 감자 품종 개발은 괴경 내 PGA 함량을 높이는 비의도적 결과를 초래할 가능성이 있다. 이러한 배경에서 신품종에 대한 정밀한 PGA 함량 분석은 감자의 식품안전성 제고와 PGA 저 함유 품종 개발을 위한 교배 모부본 확보차원에서 중요하다. 본 연구에서는 도입품종인 대서, 수미와 최근 개발된 하령, 고운, 홍영, 자영 4품종을 대상으로 괴경 부위, 저장기간별 PGA 함량변화를 분석하였다. 그 연구 결과를 요약하면 다음과 같다.

고구마 품종들의 저장중 품질성분 함량을 탐색하여 고품질 품종 육성에 기초자료로 제공하고자 경기도 화성과 수원에 여섯개의 장려품종을, 매매하여 전분가, glucose, fructose, maltose 및 sucrose함량을 조사한 바 그 결과를 요약하면 다음과 같다. 1. 전분가는 두 지역에서 모두 신율미가 가장 높았다. 2. Glucose와 fructose 함량은 품종간 지역간 변이가 심했다. 3. 두 지역 모두 maltose함량은 신율미가 가장 높았고 sucrose함량은 율미가 가장 높았다. 4. 총당함량은 식용품종인 신율미와 율미가 높았다. 5. 저장기간중 전분가, glucose, fructose, maltose 및 Sucrose함량의 큰 변화는 없었으나 지역간 차이가 있었다.