• Microbiology and Biotechnology Letters
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• v.37 no.3
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• pp.213-218
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• 2009

The goal of this study was to develop new functional pear wine using six Asian pears (Pyrus pyrifolia, Nakai), namely Wonhwang, Niitaka, Whangkeumbae, Whasan, Gamcheonbae and Chuwhangbae. To select optimal yeast and pear, we investigated the physicochemical properties of the pear wines from fermentation of musts of six pear cultivars at $25^{\circ}C$ for 7 days by several yeasts. $11.2%{\sim}12.4%$ of ethanol from musts of 'Wonhwang', 'Whangkeumbae' and 'Whasan' were produced by Saccharomyces cerevisiae K-7 and 12.8% of ethanol was also produced from 'Niitaka' by commercial Saccharomyces cerevisiae C-2. 9.9% and 11.4% of ethanol were produced from musts of 'Gamcheonbae' and 'Chuwhangbae' by Saccharomyces cerevisiae KCTC 7904, respectively. Among several pear wines, Niitaka pear wine showed the best acceptability in the sensory evaluation, and Niitaka pear wine and Whangkeumbae pear wine showed 31.1% and 27.8% of antihypertensive angiotensin I-converting enzyme(ACE) inhibitory activity, respectively. However, the other functionalities were not detected or very low. Furthermore, Niitaka-strawberry mixed fermentation wine was showed the excellent acceptability and high antihypertensive ACE inhibitory activity of 64.9%.

• Journal of Plant Biotechnology
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• v.43 no.3
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• pp.391-396
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• 2016

In this study, in vitro-cultured 'Mansoo' pear (Pyrus pyrifolia L.) plants infected with Apple stem grooving virus (ASGV) were used for testing the efficiency of the virus elimination methods. The shoot tips cut from infected plants were treated by thermotherapy ($37^{\circ}C$), cold therapy ($4^{\circ}C$), chemotherapy with ribavirin, and combination of these methods. Treatment periods were 2, 4, and 8 weeks, and concentrations of ribavirin were 20 and $40mg{\cdot}L^{-1}$. The efficiency of ASGV elimination was evaluated by reverse transcription polymerase chain reaction. The shoot survival rate was the highest at 100% after cold therapy, chemotherapy, and combination of two methods, while the rate was the lowest at 33.3% after thermotherapy for 2 weeks. The shoot survival rate after chemotherapy decreased gradually as the treatment period was prolonged. The ASGV elimination rate was the highest at 100% after ribavirin treatment at a concentration of $40mg{\cdot}L^{-1}$ and combination of ribavirin treatment and thermotherapy for 2 weeks, whereas the ASGV elimination rate after cold therapy was the lowest at 16.7%. However, the efficiency of ASGV elimination was enhanced up to 43.3% by the combination of cold therapy and ribavirin treatment. The efficiency of ASGV elimination for all treatments was increased as the treatment period was prolonged. Based on these results, we suggest that ribavirin treatment at a concentration of $20mg{\cdot}L^{-1}$ for 4 weeks or at a concentration of $40mg{\cdot}L^{-1}$ for 2 weeks combined with shoot tip culture was efficient for the elimination of ASGV from pear.

• Korean Journal of Food Science and Technology
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• v.30 no.5
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• pp.1006-1011
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• 1998

Volatile flavor components in three varieties (shingo(niitaka), mansamgil (okusankichi) and chuwhang pears) of Pear (Pyrus pyrifolia N.) were extracted for 24 hours with pentane-diethylether (1 : 1, v/v) using the LLEP (liquid-liquid extraction & perforation). Neutral fraction was separated from the extract and then analyzed by GC-FID and GC/MS equipped with a fused silica capillary column (Carbowax 20M, HP). Individual components were identified by mass spectrometry and their retention indices. The totals of 52, 47 and 22 volatiles were identified in shingo, mansamgil and chuwhang pears, respectively. Ethyl acetate, propyl acetate, hexanal, 1-hexanol, ethyl butanoate, ethyl-3-hydroxy butanoate, ethyl-2-hydroxy propanoate were the main components in each samples, though there were several differeces in composition of volatile compounds. Total contents of volatile components isolated in shingo, mansamgil and chuwhang pears were 6.972, 2.776 and 2.653 mg/kg of pears.

• Korean Journal of Agricultural Science
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• v.44 no.3
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• pp.332-338
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• 2017

This study was conducted to investigate the effect of 1-methylcyclopropene (1-MCP), a known ethylene action inhibitor, on fruit quality and incidence of physiological disorders during a simulated marketing period in new mid-season Asian pear (Pyrus pyrifolia Nakai) 'Changjo'. Flesh firmness of untreated control fruits was maintained with a hardness of 20.2 N until day 14 of simulated marketing but decreased rapidly to 6.2 N at day 21 of simulated marketing; losing its commercial quality. However, the firmness of 1-MCP treated fruits remained high (> 20.7 N) during the same period. Quality indices such as soluble solids content and titratable acidity in 'Changjo' pear did not show any significant differences during simulated marketing period regardless of 1-MCP treatment. For the difference in skin color, redness ($a^*$) tended to increase as simulated marketing period became longer, and 1-MCP treatment delayed this change by 7 days compared to the untreated fruits. No decrease occurred in ethylene production level with 1-MCP treatment in 'Changjo' pear. Meanwhile, 1-MCP treated pears showed a significantly lower respiration rate compared to the untreated fruits. Also, 1-MCP treatment effectively reduced the incidence of physiological disorders including internal flesh browning and mealiness symptoms during simulated marketing periods of 21 and 14 days, respectively. Therefore, we conclude that the use of 1-MCP is recommended for quality maintenance and for prevention of physiological disorders during simulated marketing periods of ${\geq}7days$ for mid-season Asian pear 'Changjo'.

• Korean Journal of Agricultural Science
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• v.40 no.3
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• pp.191-196
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• 2013

This study was conducted to investigate the effect of temperature during transportation and continuing shelf-life on fruit quality and the occurrence of physiological disorder to set up the appropriate exportation temperature condition in Asian pear (Pyrus pyrifolia Nakai) 'Hanareum'. In the experiment of simulated exportation headed for USA, the fruits transported at $1^{\circ}C$ showed less weight loss than those of $5^{\circ}C$. Market temperature appeared as a key factor for keeping freshness of exported pear fruits rather than transportation temperature. Quality factors such as high flesh firmness and low incidence of fruit rot and physiological disorders including core breakdown and pithiness were attained at the fruits maintained at $18^{\circ}C$. Approximately two times higher incidence of physiological disorders and of fruit decay rates were observed in the fruits distributed at $25^{\circ}C$ than the those of $18^{\circ}C$. Therefore, temperature management during marketing resulted as an important factor for maintaining fruits quality in the process of pear fruit exportation.

• Horticultural Science & Technology
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• v.34 no.3
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• pp.453-460
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• 2016

The parentage of the horticulturally important pear cultivar 'Niitaka' was confirmed by determining its S-genotypes based on the S-RNase and $PpSFBB^{-{\gamma}}$ genes, and genotyping using simple sequence repeat (SSR) markers. Previous reports suggested that the cultivars 'Amanogawa' and 'Imamuraaki' were the parents of 'Niitaka', although the cultivars 'Chojuro' and 'Shinchu' were also examined as candidate parents, along with two other cultivars. In the present study, the S-genotype of 'Niitaka' was determined to be $S^3S^9$. The $S^9$-RNase of 'Niitaka' was found to be likely inherited from the parent 'Amanogawa' ($S^1S^9$) and the $S^3$-RNase from 'Chojuro' ($S^3S^5$) or 'Shinchu' ($S^3S^5$). Based on the S-genotypes, the cultivar 'Imamuraaki' ($S^1S^6$) had no contribution to the parentage of 'Niitaka' ($S^3S^9$). A total of 67 polymorphic SSR markers were used to further confirm the parentage of 'Niitaka'. Discrepancies were found at several SSR loci between 'Niitaka' and the cultivars 'Imamuraaki' and 'Shinchu', whereas 'Niitaka' inherited alleles from 'Amanogawa' and 'Chojuro' at all SSR loci. Therefore, our findings established that 'Amanogawa' and 'Chojuro' are the parents of pear cultivar 'Niitaka', and not 'Imamuraaki' as previously reported.

• Journal of agriculture & life science
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• v.43 no.6
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• pp.59-65
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• 2009

Combinations of plant growth regulators, darkness treatments, and the order of expanding leaves for explants were evaluated for optimizing in vitro shoot regeneration rate of 'Whangkeumbae' pear. In a MS medium, supplemented with $8.88{\mu}M$ 6-benzylaminopurine (BA) and $0.49{\mu}M$ indole-3-butyric acid (IBA), green foci were observed on the surface of the callus 8 days after culture initiation. Some adventitious buds were later induced from those green foci, resulting in the appearance of normal shoots. In a medium containing $22.20{\mu}M\;BA$, the surface of the callus became compact and greenish, and many adventitious buds were formed over the entire area of the callus surface. When comparing BA concentration via histological observation, the section which had been treated with $22.20{\mu}M\;BA$ exhibited closer cell aggregation than those with $8.88{\mu}M\;BA$. The darkness treatment enhanced the formation of adventitious shoots for up to 3 weeks. The youngest two expanding leaves, proximal to the shoot apex, were proved to be the most regenerative, and yielded the highest shoot number per regenerating leaf. A fourth strength MS medium, which was supplemented with $0.54{\mu}M\;NAA$, yielded good quality plantlets, with regard to root number and root length.

• Journal of Bio-Environment Control
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• v.23 no.3
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• pp.212-220
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• 2014

This study was conducted to investigate the effect of 1-methylcyclopropene (1-MCP), a known ethylene action inhibitor, on fruit quality and incidence of physiological disorders during simulated marketing period in Asian pears (Pyrus pyrifolia Nakai) of early-season cultivar 'Hanareum' and mid-season cultivar 'Manpungbae'. Flesh firmness was decreased abruptly at 15 days after shelf-life in untreated fruit of early-season cultivar 'Hanareum' which showed less than 19N, although those of 1-MCP-treated fruits were kept high value (>28N) during 15 days of shelf-life. However, there were no distinct firmness changes during 30 days of shelf-life in mid-season cultivar 'Manpungbae' pear. Two pear cultivars did not show any considerable differences in quality indices such as soluble solids content, titratable acidity and skin color during the shelf-life regardless of 1-MCP treatment. The reduction of ethylene production level by 1-MCP treatment did not appeared in 'Hanareum' pear. Meanwhile, 1-MCP treated 'Hanareum' pears showed significantly low respiration rate during shelf-life. On the other hand, the inhibitory effect of 1-MCP was not remarkable in mid-season 'Manpungbae' pears. 1-MCP treatment completely blocked the incidence of physiological disorders including core browning and mealiness symptom during shelf-life only in early-season 'Hanareum' pears, and reduced considerably the pithiness disorder regardless of 1-MCP concentration. Consequently, we concluded that the treatment efficacy of 1-MCP is largely cultivar-dependent and the use of $1{\mu}L{\cdot}L^{-1}$ 1-MCP was recommended for the keeping quality and the prevention of physiological disorders only in early-season Asian pear 'Hanareum'.

• Food Science and Preservation
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• v.10 no.4
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• pp.447-453
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• 2003

Causal factors related to the skin disorder such as black stains during cold storage of 'Niitaka' pear fruit are of great importance to solve the postharvest disorder problems. The morphological and biochemical changes observe of pear skin affected by different harvest times and storage environments. Occurrence rate of black stain in 'Niitaka' pear fruit was the highest in newspaper bagging with 75% among various bagging materials at harvest time because of the high relative humidity within the double layer paper bags. During cold storage, the rate was 54～100% in 30 $\mu\textrm{m}$ polyethylene (PE) film packaging. As the harvest time was postponed, the rate increasedduring cold stoinge. The into was 1.5 to 2.4 times higher in pears harvested in late September than in those harvested in early and mid October. There was no significant difference in occurrence of black stain fruit between the 30 and 50 $\mu\textrm{m}$ PE film bags. The causal fungus of the black stain pear was assumed as Gloeodes pomigena (Schweintz, 1920). The treatment of 0.1～0.5 ppm ozone gas prevented the occurrence of the pear fruit black stain until 180 days after cold storage. The ozone treatment on the affected fruit was also effective in preventing the progress of the black stain.

• Horticultural Science & Technology
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• v.32 no.1
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• pp.33-40
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• 2014

This study was carried out to understand the physiological characteristics of early-matured 'Hanareum' (Pyrus pyrifolia Nakai) pears through anatomical structure and fruit characteristics and also the changes according to gibberellin (GA) treatment. The pericarp at full bloom consists of outer epidermis, hypodermis, parenchyma cell, and inner epidermis from the exterior and five types of vascular bundle tissues. Cork cell layer was formed at 70 days after full bloom (DAFB) in non-treated fruits and formed at 60 DAFB in GA treated fruits. Cell division period was from full bloom (FB) to 40 DAFB and then fruit enlargement was accomplished by the cell growth. Comparison of the fruit enlargement and fruit structure development by GA treatment or non-treatment showed that cell division of 'Hanaerum' fruits did not affect the GA treatment but fruit enlargement was affected cell growth. Fruit stalk of GA treatment fruits was larger than non-treated fruits from 40 DAFB which correspond to the period of the stop of cell division and 'Hanareum' was regarded GA treatment expedite of vascular bundle tissue growth and relatively increased nutrient transport to fruit. In addition to, average fruit quality between the non-treatment and GA treatment showed that fruit weight was higher in fruits treated by GA but firmness was lower and probably was effected fruit storing in 'Hanareum' pear.