• The Korean Journal of Food And Nutrition
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• v.30 no.1
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• pp.139-147
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• 2017

The objective of this study was to develop anti-browning agents for commercial ready-to-eat pear products, which are preferred not only to maintain the flavor, color and texture of pears, but also to increase consumers' preference. The sliced 'Shin-go (Niitaka)' pears were immersed in 5% and 10% oxidized starch, 1% citric acid, and 5% and 10% oxidized starch with addition of 0.1% sucralose for 3 minutes, and then they were packaged in vacuum sealed bags at $1^{\circ}C$ for 9 days. In order to evaluate the quality of packaged sliced pears, the quality index was determined in terms of color, firmness, soluble solids, and sensory quality. With the passage of storage time, no specific variation in firmness and soluble solids was observed. However, the ${\Delta}E$ value of the sliced pears treated with 5% oxidized starch solution was significantly lower than that of the other pears. Also, the Hunter L and b values of the sliced pears treated with 5% oxidized starch solution remained nearly constant from the beginning of storage. This observation shows that 5% oxidized starch solution was effective in reducing surface browning of sliced pears. Moreover, sliced pears treated with oxidized starch solution with addition of 0.1% sucralose were given an overall liking score which was slightly higher than that given to the other pears because of the sweetness of sucralose. In conclusion, 5% oxidized starch solution with addition of 0.1% sucralose was effective in reducing browning of sliced pears and in improving the taste of sliced pears.

• Journal of Biosystems Engineering
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• v.26 no.5
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• pp.461-468
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• 2001

Impact between fruits and other materials is a major cause of product damage in harvesting and handling systems. The oriental pears are more susceptible to bruising than other fruits such as European pears and apples, and are required more careful handling. The interest in the handling of the pears for the processing systems has raised the question of the allowable drop height to which pears can be dropped without causing objectionable damage. Drop tests on pears were conducted using an impact device developed by authors to estimate the allowable drop height without bruising. The impact device was constructed to hold in a selected orientation and to release a fruit by vacuum for dropping on to a force transducer. The drop height was adjustable for zero to 60 cm to achieve the desired distance between the bottom of the fruits and the top of the impact force transducer. The transducer was secured to 150 kg$\sub$f/ concrete block. The transducer signal was sampled every 0.17 ms with a strain gage measurement board in the micro computer where it was digitaly stored for later analysis. The selected sample fruit was Niitaka cultivar of pears which is one of the most promising fruit for export in Korea. The pears were harvested during the 1998 harvest season from an orchard in Daejeon. The sample fruit was selected from two groups which were stored for 3 months and 5 months respectively by the method of current commercial practice. The pears were allowed to stabilize at environmental condition(18$^{\circ}C$, 65% rh) of the experimental room. One hundred fifty six pears were tested from the heights of 5, 7.5. 10 and 12.5 cm while measurement were made of impact peak force, contact time, time to peak force, dwell time, pear diameter and mass. The bioyield strength and modulus of elasticity were measured using UTM immediately after each drop test. The allowable drop height was estimated on the base of bioyield strength of the pears in two ways. One was assumed the peak force during impact test increasing linearly with time, and the other was based on the actual drop test results. The computer program was developed for measuring the impact characteristics of the pears and analyzing the data obtained in the study. The peak force increased while contact times decreased with increasing drop height and contact times of the sample from the hard tissue group. The allowable drop height increased with increasing bioyield strength and contact times, and also varied with Poisson\`s ratio, mass and equilibrium radius of the pears. The allowable drop height calculated by a theoretical method was in the range from 1 to 4 cm, meanwhile, the estimated drop height considering the result of the impact test was in the range from 1 to 6 cm. Since the physical properties of fruits affected significantly the allowable drop height, the physical properties of the fruits should be considered when estimating the allowable drop height.

• 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 Plant Biology
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• v.15 no.2
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• pp.20-23
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• 1972

The isolations of fungi were observed, the isolations which were of rotting apples, pears, pine-seeds and dates cultivated in Korea, while they were living upon them. As a result of such observation. Penicillium sp. which rotted apples and pears could be isolated from the apples and pears. When the Penicillium sp. was inoculated into some fresh apples and pears, they were all rotted away. This fungus was identified as Penicillium expansum. Some fresh apples and pears inoculated with a mass of mycelium and conidia of P. janthinellun or some others inoculated with those of P. frequentans were not rotted. Though the P. expansum has been known to us a destructive not of pomaceous fruits, this fungus strain also caused the putrefaction of pears. It was found that P. expansum could be properly grown up at the temperature of $25^{\circ}C$ and pH 3~5 of media.

• Food Science and Biotechnology
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• v.18 no.6
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• pp.1379-1385
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• 2009

Quality changes of the slices processed from 'Niitaka' Asian pears (Pyrus pyrifolia) stored at $0^{\circ}C$ for up to 4 months under controlled atmosphere (CA, 1% $O_2+1%\;CO_2$) and normal air have been investigated for 4 days at $10^{\circ}C$. Respiration rate of the slices was retarded by pre-slicing storage for 4 months in CA. Electrolyte leakage was lower in the slices from pears stored for short-term than long-term and under CA than air. L and a values of the slices from whole pears stored under CA were maintained higher and lower, respectively as compared to the other. Levels of acetaldehyde and ethanol in the slices were increased by CA and long-term storage of whole pears. Content of ascorbic acid and counts of total aerobic microbes in the slices were not affected by storage conditions of whole pears. These results show that storage atmospheres and durations of whole pears affected quality changes of the slices and the conditions of pre-slicing storage should be considered as an important factor for optimizing fresh-cut procedures.

• Food Science and Preservation
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• v.10 no.2
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• pp.162-168
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• 2003

The quality characteristics and distribution of Shingo pears were investigated for 3 years to establish a reasonable grade Bevel of the fruits. Shingo pears were purchased from the orchards located in five main product areas, Naju, Sangju, Ansung, Ulsan and Asan pears. Quality factory such as greenness, uniformity, defects, size, weight, sweetness, firmness, pH and titratable acidity were measured with the pears. The average greenness (100-yellowness) in Shingo pears for 3 years was 25.27% with variation of 17.72-36.57%. The average height and diameter of Shingo pears were 94.95 mm and 105.61mm, respectively. The average weight was 566.13 g, The average scores of defects on the surface of Shingo pears damaged by physical stress and by insects were 1.23 and 1.03, respectively. The average value of soluble solids content was 12.22$^{\circ}$Brix. The average firmness was 0.96 kgf. The average values of pH and titratable acidity were 5.23 and 0.10 ％, respectively. In the results of the study based on assortment of producing districts, ranges in greenness of the pears by cultivating area was 17.23%-32.15%. Defects caused by physical stress and by insects did not show significant differences between cultivating area. Soluble solids content of the pears was ranged from 11.67$^{\circ}$Brix to 12.94$^{\circ}$Brix.

• Food Science and Preservation
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• v.24 no.3
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• pp.374-380
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• 2017

The quality characteristics of 'Xiangshui' pears (Pyrus ussuriensis) treated with different concentrations of biomass pyrolysis liquid (BPL) during storage at $25^{\circ}C$ were investigated. The weight of 'Xiangshui' pears treated with BPL declined at a slower rate than that of the control. The rot index of BPL-treated 'Xiangshui' pears decreased with increasing storage times, and treatment with 20-fold-diluted BPL resulted in the lowest rot index after storage for 12 days. The total acid content of 'Xiangshui' pears treated with 20-fold-diluted BPL was 0.19%, and was the highest after storage for 12 days. After storage for 12 days, the total sugar content of 'Xiangshui' pears treated with 20-fold-diluted BPL was 7.19%; this was significantly higher than that of the control, but not significantly different from that of pears treated with other BPL dilutions. The vitamin C content of 'Xiangshui' pears showed a decreased trend, and pears treated with 20-fold-diluted BPL had a vitamin C content of 2.21 mg/100 g after storage for 12 days and showed the least decline compared to other treatments. In addition, respiration in 'Xiangshui' pears was effectively inhibited by treatment with BPL. In conclusion, BPL treatment exerts a protective effect on the quality of 'Xiangshui' pears during storage, with 20-fold-diluted BPL being the most effective.

• Journal of the Korean Dietetic Association
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• v.13 no.2
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• pp.194-206
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• 2007

The purpose of this study was to identify dietitians' perception and purchasing pattern of fruits in elementary school lunch program. This study was conducted using mail survey from September 15 to October 30, 2006. Survey questionnaire was developed based on in-depth interview with three school food service dietitians. A total of 100 school food service dietitians in Seoul were participated. Based on the frequency analysis results, over half of respondents(69%) provides fruits every week, and 23% of respondents provides them twice a week. Strawberry, watermelon, apple, and mandarin were identified as the most frequently served fruits in Spring, Summer, Fall, and Winter, respectively. Sixty two percent of respondents indicated they offered imported fruits, such as banana and pineapple, less than 10% of total fruits. Ninety three percent of respondents selected private contract when they purchase fruits, and forty four percent of dietitians decided fruits purchasing procedure by themselves. Respondents addressed "Apples and Pears were appropriate for a dessert." and "Apples and Pears supply nutrition such as calorie and vitamin." as the advantages of offering apples and pears in school lunch menu. They also indicated difficulty in preparation work and many leftovers as the disadvantages of offering apples and pears. When purchasing apples and pears, dietitians considered taste as the first criteria and price as the second. Respondents perceived that elementary school students preferred apples and pears in a neutral level. Respondents also had higher preference for an-sim apples which can be eaten without peeling for school lunch menu and higher intentions to provide in school lunch menu. The survey results also found that respondents' intention to offer apples in school lunch menu was higher than intentions to offer pears. The implications to increase the chance of fruits offering in school lunch menu were discussed.

• Journal of Biosystems Engineering
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• v.35 no.5
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• pp.316-322
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• 2010

The packaging of fruits is very important because appropriate packaging can optimize the maintenance of freshness of fruits during their distribution in low or normal temperatures until the products reach consumers. The focus of this study was on the use of functional packaging materials for the post-harvest maintenance of the freshness of fruits. Oak charcoal has excellent far infrared emission and ethylene absorption qualities, and we developed a charcoal-processing packaging linerboard to evaluate the possibility for the use of charcoal as a functional packaging material for pears. Oriental pears of the Niitaka cultivar used in this study account for about 70% of pears harvested every year, and are a very popular domestic fruit in Korea. Pears packaged in packaging materials processed with charcoal were of significantly higher quality (p<0.05) than those packaged with conventional packaging materials, suggesting that charcoal-processed packaging materials can be used as functional packaging material for extending the storability and distribution time of fruits. Charcoal-coated linerboard was shown to be the most appropriate packaging material based on its compression strength, ethylene absorption performance, and the firmness and minimal weight loss of pears.

• Food Science and Preservation
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• v.8 no.1
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• pp.37-46
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• 2001

To examine the effects of edible coatings on the quality of fresh-cut fruits, Shingo pear was coated with several concentration of albumin, WSF(whole soy flour), dextrin and SPE (sucrose polyester) solution and quality characteristics, sensory evaluation and respiration rate were determined during storage at $4^{\circ}C$ for 10 days. Weight loss rate was reduced in coated fresh-cut pears. 2% dextrin and 1% WSF for pears were more effective in reducing weight loss rate during storage. In preventing the browning of fresh cut fruits, browning was inhibited by coating with 0.5% WSF, 1% albumin, 3% dextrin for pears. Compared with non-coated pears, 0.5% WSF, 1% albumin and 3% dextrin coating were effective in inhibiting the color changes. Even if hardness had a tendency to decrease in coated and no71-coated fruits during storage dextrin coating induced texture softening in fresh-cut pears. The changes in decrease of titratable acidity and vitamin C content and increase of pH and soluble solid were recessed by coatings but there was no differences in accordance with coating materials. Sensory evaluation of coated pears was conducted in according to coating materials and concentrations. Pears coated with 0.5% albumin, 4% dextrin, 1.0% SPE and 0.5% WSF recorded high sensory score. Among the tested coating materials and concentrations, 4% dextrin was the best in all organoleptic quality of coated pears. Respiration rate was repressed by coating with WSF and dextrin in pears.