The purpose of this study was to establish postharvest management techniques including a temperature pre-conditioning protocol for maintaining fruit quality in newly developed early season Korean pear cultivar 'Hanareum' (Pyrus pyrifolia Nakai). The fruits were treated with three different pre-conditioning temperatures (21, 25, or 29 degrees C) for 4 days according to the harvest time (103 or 110 days after full bloom, DAFB). The percent weight loss was relatively low in the fruits subjected to low pre-conditioning temperature regardless of harvest time. The firmness of the fruits treated with pre-conditioning at 21 degrees C remained high during 20 days of simulated marketing at 25 degrees C, although all treated fruits showed a general decline of firmness with extended time of simulated marketing. These fruits also showed higher appearance and a lower incidence of mealiness disorder symptoms. During the experimental periods, the production of ethylene was lower in the fruits pre-conditioned at 21 degrees C in comparison with those of treated at 25 and 29 degrees C. High respiration rates were obvious in the fruits pre-conditioned at high temperature (29 degrees C), especially in the optimum-harvested fruits, where respiration was approximately two times higher than that of fruits exposed to 21 degrees C during pre-conditioning. However, the respiration rate was similar during simulated marketing at 25 degrees C regardless of harvest time. These results demonstrated that temperature pre-conditioning at 21 degrees C is a simple and effective postharvest technique for summer harvested Korean pear cultivars including 'Hanareum'.

This study was conducted to investigate the effect of 1-methylcyclopropene (1-MCP, 1.0 mu L.L-1), a known ethylene action inhibitor, on fruit quality and incidence of physiological disorders during a simulated marketing period at 25 C for 20 days in early-season Asian pear (Pyrus pyrifolia Nakai) 'Hanareum' that had been treated with 0, 0.5, 1.2 or 2.4% GA(4+7). Weight loss of stored fruits increased with GA(4+7) concentration, and the 1-MCP treatment slightly reduced the weight loss rates during the marketing period. Flesh firmness decreased abruptly in all 1-MCP-untreated fruits as the storage period extended to 10 d, whereas the firmness of 1-MCP-treated fruits remained high (> 30 N) during 15 days shelf-life. The effect of 1-MCP was significantly reduced when fruits were subjected to increased GA concentration. Higher soluble solids content and acidity during extended shelf-life were also apparent in 1-MCP-treated `Hanareum' pears. The L-values (lightness) and hue angles of 1-MCP treated samples were higher than those of controls during 20 days shelf-life, but the a-value (redness) was lower in 1-MCP treated fruits. 1-MCP treatment did not decrease the level of ethylene evolution regardless of GA(4+7) concentration during shelf-life in early-season Asian pear 'Hanareum'. By contrast, 1-MCP treatment decreased the respiration rate significantly during shelf-life. The efficacy of 1-MCP was greatest in the GA-untreated fruit and was reduced as the GA(4+7) concentration increased. 1-MCP treatment influenced the severity of physiological disorders including core browning and mealiness: 1-MCP treatment completely blocked the incidence of core browning of during 15 days shelf-life, and reduced the severity of mealiness during 20 days shelf-life regardless of GA(4+7) concentration. Based on our results, we conclude that the use of 1 mu L.L-1 1-MCP can be of great benefit for maintaining quality and preventing physiological disorders in early-season pear cultivar 'Hanareum' pear, whereas its efficacy decreases with the Concentration of GA(4+7) whereas its efficacy gradually decreases when the concentration of GA(4+7) paste increased.

This experiment was conducted to examine the effects of a short-term treatment of high pressure $CO_2$ on shelf-life of strawberry fruit. A short-term treatment (12 hr) of 100% $CO_2$ resulted in the increase of fruit firmness up to 71.9% compared to that at harvest. The firmness of $CO_2$ treated fruit remained a significantly higher than that of control (air) up to 15 days. The alteration of pectic polymers was observed by $CO_2$ treatment such as an increase of EDTA soluble pectins and decrease of water soluble ones. The $CO_2$ treatment resulted in the increase of total amount of wall bound calcium. Pectate lyase activity, an important agent of strawberry fruit softening, was also significantly reduced by $CO_2$ treatment. Contents of soluble solids and acids of $CO_2$ treated fruit were higher than those of control fruit. Short-term treatment of high pressure $CO_2$ affected shelf-life through firmness increase whereas the visual quality and decay incidence of strawberry fruit were not affected.

This experiment examined the effects of preharvest Ca-chitosan spraying and short-term post-harvest treatment with high pCO(2) on the shelf-life of 'Seolhyang' strawberry fruit. Fruit firmness decreased when harvested late in the season and was little affected by Ca-chitosan spray treatments. Short-term treatment with high pCO(2) after harvest, however, significantly increased fruit firmness regardless of preharvest treatment The combined treatment of Ca-chitosan spray and high pCO(2) led to an additional increase in shelf-life through delay of skin disorder, fruit decay incidence and firmness loss during simulated marketing. The residual effects of both treatments, however, were reduced when fruit were harvested late in the season. Fruit firmness was more affected by high pCO(2) treatment whereas decay and visual quality were affected by preharvest spraying with Ca-chitosan. Although more research is required to determine the optimum concentration of calcium and chitosan, and the optimal spray interval, our results show that the combined treatment of preharvest Ca-chitosan spray and postharvest high pCO(2) is effective in improving strawberry fruit shelf-life by increasing firmness and delaying decay.

This study was conducted to investigate the effect of 1-methylcyclopropene (1-MCP, 1.0 μL・L -1 ), a known ethylene action inhibitor, on fruit quality and incidence of physiological disorders during a simulated marketing period at 25°C for 20 days in early-season Asian pear (Pyrus pyrifolia Nakai) ‘Hanareum’ that had been treated with 0, 0.5, 1.2 or 2.4% GA4+7. Weight loss of stored fruits increased with GA4+7 concentration, and the 1-MCP treatment slightly reduced the weight loss rates during the marketing period. Flesh firmness decreased abruptly in all 1-MCP-untreated fruits as the storage period extended to 10 d, whereas the firmness of 1-MCP-treated fruits remained high (> 30 N) during 15 days shelf-life. The effect of 1-MCP was significantly reduced when fruits were subjected to increased GA concentration. Higher soluble solids content and acidity during extended shelf-life were also apparent in 1-MCP-treated ‘Hanareum’ pears. The L-values (lightness) and hue angles of 1-MCP treated samples were higher than those of controls during 20 days shelf-life, but the a-value (redness) was lower in 1-MCP treated fruits. 1-MCP treatment did not decrease the level of ethylene evolution regardless of GA4+7 concentration during shelf-life in early-season Asian pear ‘Hanareum’. By contrast, 1-MCP treatment decreased the respiration rate significantly during shelf-life. The efficacy of 1-MCP was greatest in the GA-untreated fruit and was reduced as the GA4+7 concentration increased. 1-MCP treatment influenced the severity of physiological disorders including core browning and mealiness: 1-MCP treatment completely blocked the incidence of core browning of during 15 days shelf-life, and reduced the severity of mealiness during 20 days shelf-life regardless of GA4+7 concentration. Based on our results, we conclude that the use of 1 μL・L -1 1-MCP can be of great benefit for maintaining quality and preventing physiological disorders in early-season pear cultivar ‘Hanareum’ pear, whereas its efficacy decreases with the concentration of GA4+7 whereas its efficacy gradually decreases when the concentration of GA4+7 paste increased. Additional key words: ethylene, firmness, physiological disorder, respiration *Corresponding author: jpchun@cnu.ac.kr ※ Received 5 February 2014; Revised 24 March 2014; Accepted 29 April 2014. 본 논문은 농촌진흥청 원예특작과학원 배시험장 박사후연수과정 지원 사업에 의해 이루어진 것입니다. C 2014 Korean Society for Horticultural Science 서 언 국내 육성품종인 ‘한아름’ 배(Pyrus pyrifolia Nakai)는 수 확시기가 8월 중하순으로 조생종이며, 이 품종은 중생종에 편중된 배 품종의 불균형을 해소할 수 있을 것으로 기대되 는 품질이 우수한 품종이다(Hwang et al., 2005). 그러나 ‘신 Kor. J. Hort. Sci. Technol. 32(5), October 2014 646 고’에 비하여 수확기에 에틸렌 발생량이 높고 알코올불용성 물질 함량이 낮은 특성(Oanh et al., 2012)을 보이는데, 아직 까지 상세한 품질보전에 대한 연구가 미흡하므로 생리적 특 성의 이해 및 수확 이후 상온에서의 유통력 증진기술 개발 이 무엇보다 중요하다. 관행적으로 동양배의 과실비대 및 숙기를 촉진시키는 방법 으로 지베렐린, 에테폰, 그리고 지베렐린에 합성사이토키닌을 처리하는 방법이 주로 쓰이고 있다. 그 중 지베렐린은 과실의 단위결실(Bukovac, 1963; Inomata et al., 1992; Yamada et al., 1991)에 효과적이며 배 과실의 발육 및 성숙에 관여하는 것 으로 알려져 있다(Nakagawa et al., 1973; Yuda et al., 1984; Zhang et al., 2005, 2007a, 2007b). 현재 배 과실에서 숙기촉 진용으로 실용화되어 있는 지베렐린 도포제는 GA3 2.5% 및 GA4+7 0.2%로 구성되어 있는데, Zhang et al.(2007b)에 따르 면 배 과실 내의 total bioactive GA 수준은 만개 직후에 가 장 높고 만개 후 30-40일을 비롯한 총 5회의 수준증가가 나 타나는데 배 ‘신흥’에 있어 GA3의 수준은 만개기에만 높고 이후 세포비대기간에는 GA4의 수준 증가가 만개 후 50일 및 110일에 나타난다는 보고를 감안하면 배에 있어 GA4가 보다 직접적으로 과실비대에 관여하는 것으로 보인다. 수확 후 배 과실에서 나타나는 품질의 악화는 노화를 유 발하는 호르몬인 에틸렌이 일정 부분 관여하고 있는데 기존 의 연구결과, 조생종 배인 ‘원황’은 다른 배에 비하여 비교 적 에틸렌생합성이 높아(Lee and Chun, 2011; Lee et al., 2011) 수확 이후 빠른 품질 변화를 보이므로 에틸렌의 효과 적인 제어를 위한 에틸렌제어제의 도입 가능성을 타진하는 일은 무엇보다 중요한 연구라고 판단되고 있다(Lee et al., 2012; Moon et al., 2008). 동양배는 수확 시 과실의 숙기와 온도환경이 호흡 및 에틸렌발생에 영향을 미친다고 보고되 고 있는데(Kitamura et al., 1981) 수확 후 과실의 호흡량 증 가는 과실주변의 산소농도를 지나치게 낮추거나 이산화탄 소 농도를 높일 수 있고, 이 경우 modified atmosphere 스트 레스 유발로 과실품질에 악영향을 줄 수 있다(Kader et al., 1989). 동양배에 있어 호흡률은 조생종일수록 높고 호흡형 이 품종에 따라 다르게 나타나 ‘장십랑’은 호흡급등형을, ‘신고’ 품종은 호흡비급등형을 보이는 것으로 밝혀진 바 있 다(Jeong et al., 1998). ‘신고’ 배의 저장력 증진을 위한 controlled atmosphere 저 장의 효과가 발표된 이래(Yang, 1997), 저산소 및 고이산화 탄소 조건에서 조・만생 품종 배의 과실경도, 호흡률 및 에틸 렌 발생량의 감소 등 과실 품질 유지를 위한 긍정적인 결과 가 보고된 바 있으나(Park, 1999) 에틸렌 작용 억제제의 신 육성 품종에 대한 효능 평가 연구는 제한적인 실정이다. 따라서 본 연구는 조생종 배 과실에 대한 지베렐린 농도 별 처리가 과실 연화 촉진에 미치는 영향을 구명하고, 수확 후 1-methylcyclopropene(1-MCP)의 지베렐린 처리 과실에 대한 반응성을 검정하여 배 수확 후 관리시스템 구축의 기 초자료로 제공하고자 수행되었다.

Postharvest treatment with high-pressure CO2 helps to control decay and increase firmness in strawberries. Increases in firmness occurred through modification of calcium binding to cell wall. However, the mechanism(s) involved in Ca(2+) migration to pectic polymers and other physiological events associated with the maintenance of increased firmness are not clearly understood. The focus of this study was to find potential mechanism(s) that are associated with calcium movement, increases in firmness, or maintenance of firmness in strawberry fruit after high-pressure CO2 treatment. An increase in firmness was induced by high-pressure CO2 treatment, but not by high-pressure N2 treatment. This indicates that CO2 stimulates a change in firmness. The increase in firmness induced by high-pressure CO2 seems to involve calcium efflux. Using membrane Ca(2+) -dependent ATPase inhibitors sodium vanadate (250 μM) and erythrosin B (100 μM) delayed both the increase in firmness and calcium binding to wall polymers. Exogenous application of CaCl2 (10 mM) enhanced the firmness increase of fruit slices only when they were exposed to high-pressure CO2 . The activity of pectate lyase was downregulated by CO2 treatment, but β-galactosidase activity was not affected. The increase in strawberry firmness induced by high-pressure CO2 treatment primarily involves the efflux of calcium ions and their binding to wall polymers. These physiological changes are not induced by an anaerobic environment. The downregulation of wall-modifying enzymes, such as pectate lyase, appeared to contribute to the maintenance of firmness that was induced by high-pressure CO2 treatment.

: Physiological characteristics of two Korean golden kiwifruit cultivars, ‘Halla Gold’ and ‘Haehyang’, were compared to determine the storage potential of fruit. The soluble solid levels of the fruit were 8.9 and 6.9 o Brix in ‘Halla Gold’ and ‘Haehyang’ at harvest, respectively but increased up to 15.4 in ‘Halla Gold’ and 17.5 o Brix in ‘Haehyang’ after 2 months of storage. Major sugars were fructose and glucose, and sucrose content was relatively low regardless of cultivar. The edible quality of ‘Haehyang’ was better than ‘Halla Gold’ because of higher amount of sugars. Firmness of the fruits gradually decreased as the increase of storage period in ‘Halla Gold’ in both flesh and core tissue. Th firmness loss of ‘Haehyang’ fruit was faster in the first 2 months and then became slow. After 75 days of storage, the firmness of ‘Haehyang’ fruit was only 5.2% at harvest. Core tissue was soften enough to eat at ripe stage. Wall modifying enzyme activities including xylanase, α -L-arabinofuranosi- dase and β -galactosidase were consistently higher in ‘Haehyang’ and the activity of pectate lyase was more increased than ‘Halla Gold’ after 2 months of storage. Respiration rate of ‘Haehyang’ was higher than ‘Halla Gold’ and further increased after 2 months of storage. Weight loss was much higher in ‘Haehyang’ which showed higher rate of the firmness loss. The storage potential of golden kiwifruit was estimated to be about 2 months for ‘Haehyang’ and 3 months for ‘Halla Gold’ when determined on the basis of the fruit firmness.

In 2010, fruit rot disease was observed on the ‘Cheongsoo’ grape cultivar in a store house in Daejeon, Korea. The causal agent was determined to be a species of Pestalotiopsis not previously described in the literature. Pathogenicity tests revealed that the fungus is pathogenic to the fruit of the ‘Cheongsoo’ grape. This is the first report of fruit rot diseases on ‘Cheongsoo’ grape caused by Pestalotiopsis sp. in Korea.

This study was aimed to find the storage potential of low temperature adapted shiitake mushroom under freezing temperature ($-3^{\circ}C$). Fresh shiitake mushroom was harvested at late Feb. and cooled to target temperature, $-3^{\circ}C$ in the cooling room for 24 hr. Cooled mushroom were then placed in plastic boxes, wrapped with plastic film ($30{\mu}m$), and stored at $-3^{\circ}C$ for 2 months. Weight loss of mushroom was ranged from 2.1 to 3.2%. Dry weight per unit fresh weight, however, was slightly increased because of moisture loss. Firmness of fruit body increased from $0.95kg/cm^{-2}$ (before storage) to $1.13kg/cm^{-2}$ (after 2 month storage). About half amount of starch was lost during 2 month storage. The amount of total and reducing sugars remained relatively constant. After storage, freshness of mushroom was recovered by thawing treatment. When recovered mushroom were packaged with styrofoam tray and PVC wrapping, and exposed to ambient and $10^{\circ}C$, respectively, brown spot on the gill of fruit body was found and slight decay symptom was also found at ambient temperature only but not at $10^{\circ}C$. Results indicated that low temperature adapted shiitake mushroom has a storage potential under freezing temperature ($-3^{\circ}C$). Freezing storage technology of fresh shiitake mushroom will contribute the increase of storability up to 2 months.