• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.2
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• pp.299-304
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• 2004

This study was conducted to investigate the effects of the polyphenol fraction isolated from pear on the reduction of fat accumulation in rats fed on high fat diet for 5 weeks, which was examined by analyzing the lipid composition in serum, liver and feces biochemically. It was shown that the levels of total lipid and total cholesterol in serum were remarkably reduced in polyphenol fraction supplemented group as compared with the control group. The levels of total lipid and triglyceride were also significantly lower in polyphenol group than control group. The contents of total lipid, total cholesterol and triglyceride in feces were tended to be slightly increased in polyphenol group compared to control group. The total protein and albumin of polyphenol groups were lower compared to those of control group, which were not significant.

• 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%.

• Korean Journal of Agricultural Science
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• v.37 no.1
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• pp.13-18
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• 2010

In order to prepare the technical fundamental in production of premium quality fruits of 'Niitaka' pears, we compared the quality parameters and storability of the fruits that had various fruit set position in a cluster. The fruits set on $4^{th}$ from basal part in fruit cluster had the largest fruit size. The weight of fruits set on the higher position than $4^{th}$ from basal part in fruit cluster showed decreasing tendency. The production rates of marketable fruits which had 500g to 899g in weight were the high in $3-5^{th}$ from basal part in cluster than those in other position. The differences of fruit height and diameter which represent balanced fruit shape also showed less difference in the fruits set on $4-5^{th}$ from basal part in cluster than the fruits set closely on basal part in cluster. The fruits set on $3-4^{th}$ from basal part in cluster showed lower rate in incidence of core breakdown and pithiness disorder during 4 months of cold storage than those on the closer position to basal part in cluster.

• Preventive Nutrition and Food Science
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• v.18 no.1
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• pp.76-79
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• 2013

We evaluated antioxidant activities of heated pear juice (HPJ) exposed to 120, 130, and $140^{\circ}C$ for 2 hr. HPJ was partitioned using n-hexane, chloroform, ethyl acetate, n-butanol, and water. The ethyl acetate fraction treated at $130^{\circ}C$ for 2 hr showed strong antioxidant activity; thus, this extract was isolated and purified using silica gel column chromatography and preparative high performance liquid chromatography. The structure of the purified compound was determined using ultraviolet and mass spectrometry, $^1H$-nucelar magnetic resonance (NMR), and $^{13}C$-NMR. Antioxidant activities of the isolated compound were evaluated and compared with ${\alpha}$-tocopherol, ascorbic acid, and butylated hydroxytoluene (BHT) using DPPH and ABTS assays. The isolated compound was identified as 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one (DDMP). The DPPH radical-scavenging activity ($IC_{50}$) of DDMP occurred in the following order: ascorbic acid ($45.3{\mu}g/mL$) > ${\alpha}$-tocopherol ($69.2{\mu}g/mL$) > DDMP ($241.6{\mu}g/mL$) > BHT ($268.0{\mu}g/mL$). Furthermore, DDMP showed strong ABTS radical-scavenging activity (569.0 mg AA eq/g).

• Korean Journal of Agricultural Science
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• v.40 no.2
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• pp.79-86
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• 2013

We investigate the effect of preharvest spray of aminoethoxyvinylglycine (AVG), an inhibitor of ACC synthase activity, on fruit quality of 'Wonhwang' pear (Pyrus pyrifolia Nakai). And the effects were compared with ethephon which releasing ethylene to elucidate treatment efficacy of ethylene biosynthesis inhibitor on Asian pears. Chemicals were sprayed on 30 days before harvest with AVG (75 and 150 mg/L) and ethephon (100 mg/L), respectively. Highest flesh firmness during 21 days of shelf-life at $25^{\circ}C$ after 30 days of cold storage was attained in the fruit treated with 150 mg/L AVG (26.5N) when compared with untreated control (16.7N), while the fruits treated with 100 mg/L ethephon completely lost their marketability within 14 days of shelf-life by mass drop of firmness down to 11.6N. Low incidence of physiological disorders including pithiness and core browning were attained at the fruits treated with 150 mg/L AVG when we compared with untreated control. No occurrence of mealiness found in the fruits treated with AVG but ethephon treated fruits showed 36.4% during 14 days of shelf-life. Consequently, AVG spray at the concentration of 150mg/L on Asian pear 'Wonhwang' fruit regarded as useful preharvest management approach for keeping quality during marketing period after simulated exportation.

• Journal of Applied Biological Chemistry
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• v.59 no.4
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• pp.337-343
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• 2016

The Asian pear (Pyrus pyrifolia Nakai) has historically been one of the most popular fruits in Korea because of its sweetness and juiciness. Nowadays, 81.5 % pears of the 'Niitaka' cultivar are grown in Korea, and most of these are consumed as table fruits. Due to the increase in consumer demand for novel Asian pear varieties, developing new cultivars is of great commercial interest. Since 1984, 'Niitaka' cultivar has been introduced in Korea and 13.3 % was developed into new cultivars in the last 20 years alone. Recently, the consumption rate of fresh Asian pears has been limited. The demand for pears, especially the 'Niitaka' cultivar has no longer increased. As a result, new cultivars of Asian pears have been introduced and their properties have been investigated. This review article provides an overview of the physicochemical characteristics and antioxidant activities of new cultivars of Asian 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'.

• Food Science and Preservation
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• v.10 no.3
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• pp.272-277
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• 2003

This study was conducted to determine the minimal processing characteristics as affected by the storage duration of whole Asian pears(Pyrus pyrifolia Nakai cv. Niitaka). Before and after storage for 4 months under air at 0$^{\circ}C$, whole pears were sliced, placed in unsealed plastic bags, and kept for 4 days at 10$^{\circ}C$. Storage of whole pears increased the initial levels of electrolyte leakage, total phenols and browning index and decreased the initial content of vitamin C in pear slices. Slices from stored pears maintained higher respiration rate compared with slices from non-stored pears during keeping. The increase of electrolyte leakage, browning index and microbial number and the decrease of total phenol in slices during keeping were more fast in slices from stored pears than in those from non-stored pears. These results suggest that the minimal processing characteristics of ‘Niitaka’ pears are depending upon storage duration.

• Journal of the Korean Wood Science and Technology
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• v.46 no.3
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• pp.270-277
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• 2018

This study was conducted to identify wood species of two printing woodblocks either from the Park clan's documentary or Ji-dang documentary of Songok clan of the Milseong Park, Songok, Gyeongju, Korea. Eighty-eight woodblocks out of the total 282 woodblocks were randomly selected to compare anatomical features for the identification of wood species, using a light microscope. As a result, seven wood species were identified, and all of them were diffuse-porous hardwood species. The most significant portion, i.e., 39.8% of wood species was Carpinus laxiflora Blume. Then, Pyrus pyrifolia Nakai, Acer mono Maxim, Prunus sargentii Rehder, Tilia amurensis Rupr, Diospyros kaki Thunb, and Betula costata Trautv was 25.0%, 15.9%, 10.2%, 3.4%, 3.4% and 2.3%, respectively, indicating that all diffuse-porous hardwood species had been used for the woodblocks. It was believed that diffuse-porous hardwoods had been used because they provided an easy of engraving complex Chinese letters, of acquiring these wood species in Gyeongju areas, and a high resistance to repeated printing.

• Korean Journal of Agricultural Science
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• v.36 no.2
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• pp.199-209
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• 2009

For increasing the consumption of pear, the pear wines were made by using eight different kinds of yeast. The chemical properties, such as pH, acidity, ethanol and sugar contents, and the consumer acceptance of various pear wines were analyzed. In analysis result of chemical properties, the value of pH was decreased and the acidity was increased until few days, and then retained during fermentation. The ethanol content was increased and the sugar content was decreased during fermentation. The pear wine brewed by B yeast (Lalnin, Saccharomyces cerevisiae) among eight different kinds of yeast had the highest content of ethanol, also this wine was represented the most consumer acceptance by the panels who consist of two age groups such as 20's to 30's and 50's to 60's. Therefore, we chose the yeast B for analyzing the effect of additives during fermentation. As the additives, the $K_2S_2O_5$ and ammonium phosphate as the disinfectant and hemicellulase and pectinase as fermenting conditioner were added into the pear wine brewed by yeast B. When additives are added, the chemical properties were the same as followed. Te values of pH was lower than when additives were not added(control). The acidity was he highest when ammonium phosphate was added, but the acidity was not changed after 4 day fermentation. Sugar contents when added $K_2S_2O_5$ 350ppm was shown the fastest deceasing, and it was orderly decreased as control, ammonium phosphate, hemicellulase, pectinase, and $K_2S_2O_5$ 175ppm. The decreasing rate of sugar content of these 6 test groups during fermentation gradually decreased without a big changes and the after 7 day fermentation, sugar contents were seldom decreased and the final sugar content was $9.5{\sim}9.8^{\circ}Brix$. In terms of change of the content of ethanol, all test groups generated 11~12.4% ethanol after 7 day fermentation. The group where ammonium phosphate was added generated 12.4% alcohol, which is the fastest speed and the group, which hemicellulase additive was added, showed generally slow alcohol generation rate. In terms of ethanol contents, the non-additive group and $K_2S_2O_5$ additive group showed 0.05%, which is very low, and hemicellulase and pectinase additive group is more than 0.5% which is rather high.