• Journal of Applied Biological Chemistry
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• v.43 no.2
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• pp.94-100
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• 2000

An analytical method was developed to determine abamectin and milbemectin residues in apple, pear, and citrus using HPLC with ultraviolet absorption detection. Abamectin and milbemectin were extracted with methanol from apple, pear, and citrus samples. The extract was diluted with saline water and dichloromethane partition was followed to recover the compounds from the aqueous phase. Florisil column chromatography and aminopropyl solid-phase extraction were employed as cleanup methods to remove most of co-extractives from the sample extract. Reverse-phase HPLC using an octadecylsilyl column was successfully applied to separate and quantitate abamectin and milbemectin residues in sample extracts at the wavelength of 245 nm. Recoveries of abamectin and milbemectin from fortified samples ranged 80.4~90.3% and 90.9~96.8%, respectively. Relative standard deviations of the analytical method were less than 10% for both acaricides. Detection limit of the analytical method was 0.003 mg/kg sample for all the analytes. The proposed method was reproducible and sensitive enough to evaluate terminal residues of abamectin and milbemectin in apple, pear, and citrus.

• Mycobiology
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• v.39 no.3
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• pp.170-173
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• 2011

Kluyveromyces fragilis KCTC 7260 and Saccharomyces cerevisiae KCTC 7904, which both grew well in pear marc extract, were selected and their growth profiles and physiological functionalities were determined. Both of the selected yeasts established maximal growth by 20 hr of cultivation at $30^{\circ}C$ in pear marc extract. The cell-free extracts showed high antihypertensive angiotensin I-converting enzyme inhibitory activity of 68.9% and 52.1%, respectively. The extracts also displayed 9.2 U/mL and 12.0 U/mL of protease activity, respectively.

• Preventive Nutrition and Food Science
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• v.5 no.1
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• pp.32-36
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• 2000

Prickly pear juice(PPJ) extracted from prickly pear fruit (Opuntia ficus-indica)was used as raw material for the production of alcoholic beverages. Prickly pear juice (PPJ) had 0.88 oBrix of soluble solid, pH 3.96 and 0.14% of total acidity. Alcohol fermentation of 25% PPJ including 22 oBrix of sugar and 1$\times$106 of inoculum was suitable for alcohol fermentation indicating the rapid decrease of sugar content. The 22 oBrix of sugar in PPJ (25%)GJ (50%) mixture was changed to 6.5 oBrix after fermentation at 3$0^{\circ}C$ for 7 days. The alcohol content was 9.2% (w/v). PPJ (70%)/GJ (30%) mixture produced alcoholic beverage with 6.9% alcohol content resulting in the gradual decrease of soluble for 7 days. On the other hand, PPJ (50%)/GJ(50%) mixture carried out completely the alcohol fermentation at 22$^{\circ}C$ for 6 days and enhanced the red color of alcoholic beverages.

• Food Science and Preservation
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• v.23 no.2
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• pp.174-179
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• 2016

This study was to prepared vinegars using three kinds of pear cultivar with different maturities, 'Wonhwang', 'Niitaka', and 'Chuhwangbae', and investigate their physicochemical characteristics and antioxidant activities. Result showed that the firmness of 'Wonhwang' was much lower than other pear cultivars. No significant difference in soluble solid content was found among three pear cultivars. The total acidity of 'Chuhwangbae' pear vinegar was 4.89~7.98%, which was higher than that those of 'Wonhwang' and 'Niitaka' vinegars. The color of 'Niitaka' vinegar had a lower lightness and redness values, but a higher yellowness value, compared with the other two vinegars. The free sugar contents were mainly composed of fructose, glucose, and sorbitol, with the greatest content of sorbitol in all three peer vinegars. The total phenolics and flavonoids contents were 35.2~55.3 and 8.4~14.4 mg/100 mL, respectively. Antioxidant activity had a positive correlation with total phenolic contents. The DPPH free radical scavenging and $ABTS^+$ radical scavenging activity were 45.0~62.1% and 73.8~78.2%, respectively. From these results, we confirmed that immature pear cultivars such as 'Wonhwang', 'Niitaka' and 'Chuhwangbae' could be used as a raw materials to prepare vinegar regardless of maturity.

• Korean journal of food and cookery science
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• v.12 no.4
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• pp.506-510
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• 1996

The stability of prickly pear color as affected by pH, metal ions, sugar and acids was studied. The color of prickly pear was most stable at pH 4 and 5. Metal ions (Fe, Cu) at a level of 100 ppm caused a decrease in stability compared to that of the control, whereas pigment of prickly pear was stable at 100 ppm of Sn ion And the color of prickly pear was stable at 0.15 M fructose. Both 100 and 500 ppm ascorbic acid had the greatest effect on stability, while citric acid, phosphoric acid and tartaric acid had no effect on stability compared to that of the control. Based on the data presented, it was concluded that under selected conditions prickly pear pigment should find application as natural food colorants.

• Korean Journal of Organic Agriculture
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• v.26 no.2
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• pp.245-257
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• 2018

The efficacy of different control techniques against the large black chafer, Holotrichia parallela Motschulsky (Coleoptera: Scarabaeidae), in organic pear (Pyrus pyrifolia) orchards was evaluated. In this study, field trials were conducted in three locations in Korea-Naju, Hampyeong, and Boseong-to evaluate different techniques to suppress these beetles. Pheromone traps, bio-insecticides (Hongmengye and Melchungdaejang), and a combination of the two were applied as treatments. In Naju, Hampyeong, and Boseong, the highest number of adult H. parallela were caught in the control plots (n=45, n=39, and n=20, respectively), while the fewest were caught in the pheromone plus bio-insecticide plot (n=19) in Naju and in the combined treatment plot in Hampyeong (n=10). In Naju, the greatest leaf damage was observed in the control (66%), and in all locations (Naju, Boseong, and Hampyeong), the least damage occurred in the combined treatment plots (42%, 36%, and 24%, respectively). Regarding the tree canopy, the greatest leaf damage was observed in the upper canopy, and less damage was observed in the lower canopy. These results demonstrate that the combination of sex pheromone traps and bio-insecticides can be used to manage H. parallela in organic pear orchards.

• Korean Journal of Organic Agriculture
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• v.26 no.2
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• pp.259-268
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• 2018

The study investigated the efficacy of four different essential oils on the repellent responses of large black chafer (Holotrichia parallela) Motschulsky (Coleoptera: Scarabaeidae) in organic pear (Pyrus pyrifolia) orchards. Cinnamon, pine, peppermint, and eucalyptus oils were used, and the behavioral responses and repellent effects against H. parallela were investigated under laboratory and field conditions. Adult beetle responses to different oils were examined using a Y-tube olfactometer in the laboratory and four absorbent blocks with each oil in the field. The repellent responses rates of H. parallela were 100% for cinnamon oil; however, only 67% of adult beetles avoided peppermint and eucalyptus oil in the Y-tube olfactometer bioassay. In the field tests, the least damage to leaves was observed on trees treated with cinnamon oil, whereas the most damage was observed in the control (non-treated) trees and those treated with peppermint oil, followed by eucalyptus and pine oil. Therefore, cinnamon oil can be used as a repellent to avoid damage form large black chafers in organic pear orchards.

• Korean Journal of Environmental Agriculture
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• v.26 no.2
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• pp.171-178
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• 2007

Diffusion and accumulation of ethoprophos in fruit such as apple and two types of pears were examined by dipping them into the solution of ethoprophos. The effective diffusivities of ethoprophos at the skin and flesh of apple and pear were determined by simulation their experimental accumulation curves with calculated ones from the model assuming consecutive diffusion of ethoprophos from skin to flesh. Its effective diffusivity at the flesh with higher content of water were higher, $\sim10^{-10}\;m^2/s$, regardless of the types of fruits, while that at the skin was small, $\sim10^{-12}\;m^2/s$ and increased with the order of 'Niitaka' pear < 'Whangkeumbae' pear < 'Fuji' apple. The variation in the concentration of ethoprophos in its solution did not induce any change in affecting its effective diffusivity at the flesh of 'Whangkeumbae' pear, but the increase in the concentration caused the increase in its effective diffusivity at the skin. The penetration rate of ethoprophos at the skin was an important factor in determining its accumulation rate in fruit.

• Korean journal of applied entomology
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• v.21 no.4 s.53
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• pp.207-210
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• 1982

The studies were carried out to examine susceptibility or resistance of junipers as an inform ediate host of pear rust, to select effective fungicides to pear and juniper rust, and to determine their application time. The telia were formed abundanty on Juniperus chinensis var. kaizuka, moderately on J. chinensis, J. chinensis var. sargentii and J. virginiana, but little on J. chinensis var. globosa and J. utilis. The telia from the junipers were pathogenic to pear. Spraying juniper host with the fungicide Actidione in the 1st and End parts of April greaty inhibited swelling of telia as well as germination of teliospores. The two or three applications of Bayleton at the end of April to May 10 were remarkably effective for the control of pear rust. Fungicide sprays just before rain were more effective than those after rain.

• Korean Journal of Weed Science
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• v.7 no.3
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• pp.337-347
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• 1987

Spary and vapor drift injuries of apple, pear, and peach seedling caused by soil-applied oxyfluorfen were studied in a greenhouse. Bud bursting rate of all fruit trees was reduced by both spray and vapor drifts of oxyfluorfen, but reduction in bud bursting rate of pear and peach was greater than that of apple trees. Reduction in the number of leaves per shoot of apple and peach was greater than that of pear trees. Leaf injury of pear was most severe and occurred earliest, but leaves of peach were least injured, Leaf injuries of pear and apple were caused by both spray and vapor drifts, but leaves of peach was injured largely by vapor drift. Reduction in shoot growth of and pear was greater than that of peach trees. Shoot growth of pear was more rapidly retared compared with apple trees. In the field, oxyfluorfen delayed the time of bud bursting in young apple trees. Oxyfluorfen applied between initiation and completion of bud bursting delayed bud bursting more than earlier application although ultimate number of bursted buds was similar to control. The number of leaves per shoot and total length of shoots were lower than control until 40 days after application of oxyfluorfen, and then were similar to control because of vigorous growth after May.