• Korean Journal of Food Science and Technology
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• v.34 no.2
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• pp.180-185
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• 2002

Volatile flavor components in three pear varieties (Pyrus pyriforia N.) of traditional cultivar, Bongri, Hwangsilri and Yongmokri, were collected by SDE method using the mixture of n-pentane and diethylether as an extract solvent and were identified by GC/MS. Among 97 compounds identified from all varieties, there were 72, 58 and 66 components in Bongri, Hwangsilri and Yongmokri, respectively. Ethyl acetate was the dominant constituent in all cultivars and also volatile profiles contained large quantity of ethanol and acetic acid. Butyl acetate identified as a main component in Bongri was not found in other pears, but in Hwangrilri and Yongmokri only 4 to 5 esters played important role in total volatile flavor composition. The volatile profiles of these three varieties were characterized by compounds in group of aldehydes, esters, alcohols, acids and ketones. As classified by functional group of separated and identified components, esters and alcohols in Bongri, alcohols in Hwangsilri, and esters in Yongmokri were roled as the title in composition of volatile flavor components. Although small amount, Yongmokri had the highest rate of volatile production at 6.552 mg/kg of pear while Hwangsilri produced the lowest at 4.175 mg/kg of pear.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.2
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• pp.195-202
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• 2008

This study was performed to examine the effects of electron beam irradiation on volatile flavor components of Shingo pear (Pyrus pyrifolia cv. Niitaka) and on their changes according to storing period following irradiation. Volatile flavor components in pear were extracted using simultaneous steam distillation and extraction (SDE) apparatus and analyzed by GC/MS. 46 components were identified in control whereas 45, 44, 48 and 51 components were identified in irradiated samples by electron beam at 0.25, 0.5, 1, and 3 kGy, respectively. Hexanal, n-hexanol, and (E)-2-hexenal were identified as the major volatile flavor components of all samples. The characteristic volatile flavor components of irradiated pear by electron beam were similar to those of control, and their effects depending on irradiation source were not different. In addition, there was no noticeable change in volatile flavor components of pear with storage at $4^{\circ}C$ for 30 days or with irradiation. Sensory evaluation indicated that the consumer receptiveness tended to be higher at a low level of radiation dose under 1 kGy than control, albeit not significant. Therefore, electron beam irradiation at low level of radiation dose under 1 kGy could be considered as an effective method to exterminate vermin and thus to improve the shelf-stability of pear without deterioration.

• Food Science and Preservation
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• v.9 no.4
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• pp.391-395
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• 2002

Thinned fruits, apple, pear and peach were investigated into chemical components and physiological activities. On proximate compositions, crude protein, crude fat and ash of thinned fruits were higher than those of ripe fruits, showing lower carbohydrate in thinned fruits. The contents of inorganic substance were Ca, Mg, P, Na, K and B in order. On heavy metals, As, Cd, Cr and Hg were not detected and Ge, Mo, Ni and Pb were trace. Organic acid in thinned apple and peach were detected as tartaric acid, citric acid, malic acid and succinic acid, but thinned pear did not contain citric acid. Free sugars in thinned pear and peach were composed of glucose, fructose and sucrose but sucrose was not detected in thinned apple. Contents of insoluble dietary fiber in thinned fruits were higher than soluble dietary fiber. The thinned apple extracts showed high antioxidant activity. Nitrite scavenging activity of thinned apple and pear extracts were 71∼80 e/o and 61∼63% at pH 1.2, respectively. Tyrosinase inhibitory activity of thinned pear extracts was 61.0∼89.4 ％, however peach extinct showed no activity.

• Korean journal of applied entomology
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• v.58 no.2
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• pp.159-164
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• 2019

The purpose of this study was to investigate whether leaf damage in pear orchards caused by large black chafer beetles can be controlled through net traps and clove oil treatment. In June 2017, we measured large black chafer beetle population density and leaf damage rates in two orchards, located in Boseong and Hampyeong, under three treatments: net, net plus clove oil, and control. In order to evaluate the effect of net position on the adult beetles, nets were placed outside the orchard and along the upper and lower parts of a horizontal trellis. The adult beetle population density was 20.4 to 34.7% lower in the net alone treatment, and 21.1 to 38.1% lower in the combined net and clove oil treatment than in the control. The adult beetle population density was 10.9-14.4 times higher outside the orchard and 5.1 to 9.1 times higher in the upper parts of the horizontal trellis than in the lower parts of the horizontal trellis. Leaf damage under both the net only and net plus clove oil treatments was significantly lower than that in the control at both sites. Therefore, intensive net installation around orchards may be a practical organic alternative to prevent leaf damage caused by large black chafer beetles.

• 한국약용작물학회:학술대회논문집
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• 2008.11a
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• pp.384-385
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• 2008

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2004.05a
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• pp.147-147
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• 2004

• Korean Journal of Agricultural and Forest Meteorology
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• v.19 no.2
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• pp.43-53
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• 2017

This study aims to analyze the effect of typhoons on pear production. Pears are typical fruits that are vulnerable to typhoon damages, so typhoons are negatively associated with pear productivity. However, relatively less pear damages by typhoons in the main pear production area, comparing to the average in Korea, have been reported. The main production area seems to adopt better agricultural techniques or practices to cope with natural disasters such as typhoons. Thus, this study tests the hypothesis that there are differences of production losses due to typhoons between the main pear production area and the rest using the stochastic frontier analysis. The main production area is defined by Location Quotient Index (LQI), and we found that LQI had a significant effect to decrease the productivity losses in the main production areas, which shows that those production areas alleviated the pear production loss due to typhoons.

• Horticultural Science & Technology
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• v.34 no.6
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• pp.959-965
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• 2016

In 1994, a new cultivar 'Joyskin' was created from a cross between the cultivars 'Whangkeumbae' and 'Waseaka' at the Pear Research Institute of the National Institute of Horticultural and Herbal Science, Rural Development Administration. In 2006, the 'Joyskin' was selected from among the 317 seedlings resulting from the cross for its skin and taste qualities. Regional adaptation tests were conducted in nine regions and in ten experimental plots from 2006 to 2011. The cultivar was named in 2011. 'Joyskin' showed a vigorous growth habit and semi-spread characteristics similar to 'Whangkeumbae'. The average full bloom date for 'Joyskin' was April 21st, which was also similar to 'Whangkeumbae'. The optimum fruit ripening time was September 6-8th, which was six or eight days earlier than 'Whangkeumbae'. The fruit was round in shape and the skin was a golden yellow color at maturity. The average fruit weight was 320 g and the flesh firmness was $2.5kg/8mm{\varphi}$. The firmness of the fruit skin determined by a blade-type plunger of texture analyzer was 22.9 N, which was significantly different from that of 'Whangkeumbae' 29.9N. Stone cell analysis of 'Joyskin' by phloroglucinol-HCl, showed that 'Joyskin' stone cells were small in size and few in numbers cpmpared to those of cultivars of was 'Manpungbae', 'Niitaka', and 'Whangkeumbae'. The patent application for 'Joyskin' was submitted in April, 2012 (Grant No. 2012-337). In 2016, 'Joyskin' (Grant No. 5895) was registered as a separate record, with uniformity and stability per Korean Seed Industry Law.

• Horticultural Science & Technology
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• v.30 no.4
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• pp.345-356
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• 2012

We investigated the changes of fruit quality parameters, polysaccharide contents and cell wall components during maturation and ripening of two Korean pear cultivar 'Hanareum' and 'Manpungbae' compared with 'Niitaka' pear (Pyrus pyrifolia Nakai) which showed different physiological maturity based on days after full bloom (DAFB). Flesh firmness decreased continuously with fruit development and maturation, reaching a final level of 29.4, 33.5, and 27.4N at maturity in 'Hanareum' (127 DAFB), 'Manpungbae' (163 DAFB), and 'Niitaka' (170 DAFB), respectively. The level of ethylene production was very low in early season 'Hanareum' pear which showed at most 0.39 ${\mu}L{\cdot}L^{-1}$ at maturity and no ethylene was detected in 'Manpungbae' and 'Niitaka' at maturity. Fructose was the most abundant soluble sugar during fruit maturation in the pears tested and an increase of sucrose was observed during fruit ripening in the Asian pears commonly. Ethanol insoluble solids (EIS) content decreased gradually with different levels among the pear cultivars as fruit ripens consisted of 10.79, 12.72, and 12.75 $mg{\cdot}g^{-1}$ FW. The amount of total soluble polyuronides was higher in early season cultivars 'Hanareum' than those of mid-season cultivar 'Manpungbae' and 'Niitaka'. In 'Niitaka' which harvested most late season, the level of 4% KOH soluble hemicelluloses was lower than 'Hanareum' and 'Manpungbae' and maintained constantly during fruit ripening period. Cellulosic residues were determined high level in 'Niitaka' which showed 612.33 ${\mu}g{\cdot}mg^{-1}$ EIS at maturity when compared with 'Hanareum' (408.0 ${\mu}g{\cdot}mg^{-1}$ EIS) and 'Manpungbae' (538.67 ${\mu}g{\cdot}mg^{-1}$ EIS). The main constituents of cell wall neutral sugars which consisted of arabinose, xylose, galactose, and glucose were decreased gradually with onset of fruit ripening regardless of cultivar. Arabinose which was predominant in 'Hanareum' pear decreased at the last stage of ripening, but the changes of cell wall neutral sugar during ripening were not occurred in 'Niitaka' pear. The change of molecular mass distribution in water soluble pectin observed dominantly at the early stage of fruit development. Depolymerization of 4% KOH-soluble hemicelluloses and degradation of xyloglucan showed in early-season cultivar 'Hanareum' during fruit maturation, and degradation of those fractions were detected only at the early stage fruit development in mid-season cultivar 'Manpungbae' and 'Niitaka'. The molecular mass profile of CDTA soluble pectin, $Na_2CO_3$-SP and 24% KOH soluble hemicelluloses showed no significant change during fruit maturation regardless of cultivar.

• Food Science and Preservation
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• v.23 no.6
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• pp.778-787
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• 2016

Fermented vinegars using pear was compared according to the appled side materials. Quality characteristics of three kinds of the fermented vinegars (pear vinegar, PV; pear black rice vinegar, PBV; pear mint vinegar, PMV) were investigated, which includes pH, total acidity, colors, the contents of sugar, amino acids, total polyphenol, and total flavonoid, ${\alpha}^{\prime}{\alpha}-diphenyl-{\beta}-pycrylhydrazyl$ (DPPH) radical scavenging ability, and sensory evaluation. Brown rice vinegar (BRV) was used as a control. The pH and total acidity of the fermented pear vinegars were significantly different showing the range of 3.17~3.43 and 4.01~5.05%, respectively (p<0.05). The sugar contents of PV and PMV were significantly higher than other vinegars (p<0.05). L, a, and b values were the highest in PV, PBV, and PMV, respectively. Among the four vinegars, the essential amino acids were the highest in PV with the order of lysine, isoleucine, valine, and threonine. Besides, the fermented pear vinegars have many non-essential amino acids such as glutamic acid and aspartic acid. The aspartic acid content was the highest in PV while glutamic acid content was the highest in BRV. The total polyphenol content was the highest in PV while total flavonoid content was the highest in PBV. The DPPH radical scavenging ability (%) was the highest in PV. In sensory evaluation, PBV showed the highest color, taste and overall preference scores. These results show that pear would be desirable to prepare high-quality vinegars and functional foods.