• Food Science and Preservation
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• v.19 no.4
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• pp.485-491
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• 2012

This study was conducted to investigate the pH, soluble solid contents, color difference, mineral contents, free sugar contents, and sensory quality of infrared- and cold-air-dried peaches. The pH, soluble solid contents, and free sugar contents of the infrared-dried peaches were higher than those of the cold-air-dried peaches. In the Hunter's color value, the L and ${\Delta}E$ values of the infrared-dried peaches were higher than those of the cold-air-dried peaches; but the a and b values of the cold-air-dried peaches were higher than those of the infrared-dried peaches. The major organic acids of the dried peaches were citric acid, malic acid, and oxalic acid. The minerals with the highest to lowest contents, in that order, were K, Mg, Ca, Na, Fe, Zn, Cu, and Al. The mineral contents of the cold-air-dried peaches were higher than those of the infrared-dried peaches. The appearance and taste of the infrared-dried peaches were better than those of the cold-air-dried peaches. These results indicate that infrared drying is the effective drying method for the production of high-quality dried peaches.

• Korean Journal of Food Science and Technology
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• v.35 no.6
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• pp.1233-1236
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• 2003

Various precooling treatments were applied to prolong the freshness of mibaek peaches that were harvested during the summer season. Peaches were cooled from $25.9^{\circ}C$ to $5^{\circ}C$ within 3 hours by a pressure cooler, and the cooling rate was accelerated by increasing the air velocity and static pressure. Respiration and ethylene production rates of mibaek peaches were about four times faster at $20^{\circ}C$ than at $7^{\circ}C$, while precooled peaches had better visual quality at $7^{\circ}C$ than at $20^{\circ}C$. Also, precooled peaches had higher soluble solid and ascorbic acid content than non-precooled peaches when stored at 7 and $20^{\circ}C$. However, weight loss was lower in precooled peaches than in non-precooled peaches during storage.

• Korean Journal of Food Science and Technology
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• v.4 no.1
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• pp.6-12
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• 1972

Fay Elberta freestone peaches were harvested at four maturity levels as judged by skin color and firmness. They were ripened at $68^{\circ}F$ under 80 percent relative humidity for 4, 6, 8 and 10 days respectively prior to canning. Results indicate that both harvest maturity and ripening conditions are important factors influencing quality, flavor and composition of canned freestone peaches. Peaches harvested at $18{\sim}24$ pounds on a Magness-Taylor pressure tester with a 7/16' plunger(M1) failed to ripen satisfactorily. Fruits harvested at $13{\sim}17$ pounds (M2) pressure test ripened successfully at $68^{\circ}F$ within 6 to 8 days; and those harvested at 6 to 12 pounds (M3) needed 4 days for ripening at $68^{\circ}F$. Tree-ripened fruits (M4) were undesirable for canning because of the high percentage of bruised fruits. The optimum firmness for canning appears to be in the range of 1.5 to 3.0 pounds. The titratable acidity of peaches decreased during maturation and ripening. The tannin content of peaches at M1 maturity decreased with ripening at $68^{\circ}F$. But no appreciable change was observed in the M2 and M3 series which were ripened at $68^{\circ}F$ for 4 to 10 days. The volatile reducing substances (V.R.S.) increased as the peaches developed on the tree and also during post-harvest ripening. The effect of harvest maturity and post-harvest ripening on color grade of the canned peaches is presented. Little difference was found in the flavor and composition of peaches peeled by the cup-down lye peeling and the steam-peeling methods. The cup-down lye-peeling method might be most advantageous because of its higher peeling efficiency.

• Food Science and Preservation
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• v.8 no.3
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• pp.246-251
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• 2001

This study was conducted to investigate the change of qualities of peaches by different packing types and humidity during storage period. The weight loss ratios of 'Kulakatawase' and 'Mibaek' by non-packing were about 6.8% and 4.9% for 4 days storage at room temperature, respectively whereas, the peaches by packing with 30㎛ LDPE were less than 1% for 25 days storage at low temperature and high humidity(95 $\pm$3%). The firmness values of the peaches were not decreased during storage at low temperature compared to the firmness values of the peaches during storage at room temperature. Little difference of total acidity and soluble solids of the peaches was during storage at low temperature. The contents of fructose and glucose in peaches were increased slightly after storage for 25 days but that of sucrose was decreased slightly. When peaches were stored at low temperature(0∼2$\^{C}$) and high humidity(95$\pm$ 3%) after packing with 30㎛ LDPE or 25㎛ perforated polyolefin film 'Kurakatawase ' and 'Mibaek' were able to storage for 20 and 25days, respectively.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1267-1267
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• 2001

The existing fruit sorter has the method of tilting tray and extracting fruits by the action of solenoid or springs. In peaches, the most sort processing is supported by man because the sorter make fatal damage to peaches. In order to sustain commodity and quality of peach non-destructive, non-contact and real time based sorter was needed. This study was performed to develop peach sorter using near-infrared spectroscopy in real time and nondestructively. The prototype was developed to decrease internal and external damage of peach caused by the sorter, which had a way of extracting tray with it. To decrease positioning error of measuring sugar contents in peaches, fiber optic with two direction diverged was developed and attached to the prototype. The program for sorting and operating the prototype was developed using visual basic 6.0 language to measure several quality index such as chlorophyll, some defect, sugar contents. The all sorting result was saved to return farmers for being index of good quality production. Using the prototype, program and MLR(multiple linear regression) model, it was possible to estimate sugar content of peaches with the determination coefficient of 0.71 and SEC of 0.42bx using 16 wavelengths. The developed MLR model had determination coefficient of 0.69, and SEP of 0.49bx, it was better result than single point measurement of 1999's. The peach sweetness grading system based on NIR reflectance method, which consists of photodiode-array sensor, quartz-halogen lamp and fiber optic diverged two bundles for transmitting the light and detecting the reflected light, was developed and evaluated. It was possible to predict the soluble solid contents of peaches in real time and nondestructively using the system which had the accuracy of 91 percentage and the capacity of 7,200 peaches per an hour for grading 2 classes by sugar contents. Draining is one of important factors for production peaches having good qualities. The reason why one farm's product belows others could be estimated for bad draining, over-much nitrogen fertilizer, soil characteristics, etc. After this, the report saved by the peach grading system will have to be good materials to farmers for production high quality peaches. They could share the result or compare with others and diagnose their cultural practice.

• Preventive Nutrition and Food Science
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• v.6 no.2
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• pp.107-111
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• 2001

Physical and chemical characteristics of four white-and one yellow-fleshed peach cultivars were compared at optimum maturity stage. In addition, differences of phenolic composition, polyphenol oxidase (PPO) activities and PPO isozyme patterns in two peach types were also investigated. There are no significant differences in firmness and color values between two peach types, except for "Yumyung", a white-fleshed peach with the highest firmness, and "Hwangdo", a yellow-fleshed peach with the highest yellowness (b)* value. In general, the soluble solid/titratable acidity ratios, ascorbic acid and total phenolic contents were significantly higher for white-fleshed peaches than those for yellow-fleshed peach (p<0.05). Three major phenolic compounds, catechin, neochlorogenic acid and chlorogenic acid, were found in both the white-and yellow-fleshed peaches. Among them, catechin was the predominant phenolic compound in the white-fleshed peaches, followed by neochlorogenic acid, and chlorogenic acid. Meanwhile, neochlorogenic acid was present in the highest level of the yellow-fleshed peach, but levels of two other phenolic compounds were lower. PPO activities of the white-fleshed peaches were generally higher than that of the yellow-fleshed peach, with the one major band and two minor bands, and there were no big differences in PPO isozyme patterns between two different peach cultivars.

• Korean Journal of Food Science and Technology
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• v.19 no.5
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• pp.453-455
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• 1987

Swollen commercially canned grapes and peaches were collected to investigate the microorganisms involved in their spoilage. 6 of 52 grape and 19 of 23 peach samples were found to be spoiled by microorganisms. Yeasts were the only spoilage microorganisms of canned grapes with Saccharomyces cerevisiae as the leading spoilage yeast. Yeasts and bacteria were found from spoiled canned peaches. S. cerevisiae and Torulopsis stellata were the most important spoilage yeasts of canned peaches. Lactic acid bacteria, belonging to genera of Lactobacillus and Leuconostoc, were the most frequently found spoilage bacteria. Only one spore-forming bacterium, Bacillus licheniformis, was involved in the spoilage of canned peaches.

• Journal of Biosystems Engineering
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• v.19 no.1
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• pp.33-41
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• 1994

In order to evaluate the quality of peaches non-destructively, the surface color and spectral reflectances of KURAKATAWASE, MIBAEKTO, and OKUBO cultivar were measured. Also an attempt was made to correlate reflectance characteristics and tristimulus values with quality evaluation parameters such as chlorophyll content, soluble solids, anthocyanin content, and firmness. Further analysis of the correlation coefficients showed that spectral reflectance would be effective for the quality evaluation of peaches.

• Korean Journal of Food Science and Technology
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• v.31 no.5
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• pp.1227-1234
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• 1999

Modified atmosphere packaging of peaches(Prunus persica L. Batsch) was investigated to extend their freshness during distribution. Peaches were packaged in the PE film(20LD, 40LD), the PE film modified by addition of 5%(w/w) zeolite(20CK, 40CK), and the PE film containing $Purafil^{\circledR}$ sachet(20LP, 40LP). Quality indexes of peaches during storage at $20^{\circ}C$ were measured in terms of weight loss, soluble solids content, pH, titratable activity, firmness, color and sensory properties. Gas composition and ethylene content In the film bags changed rapidly at the early stage of storage. Within 8 days, weight loss of the unpacked control increased upto ll.8% but those of the packaged remained below 2%. There was no significant difference in soluble solids content and pH in all the treatments. Ethanol content of peaches packed in 40LD was 12.88 mL/kg and acetaldehyde content in 40CK was $160\;{\mu}L/kg$ for 8 days. Peaches packed in 20CK showed a good visual and sensory Quality. The result suggested that active packaging treatment such as 20CK could be used for extending freshness of peaches during transport period at ambient temperature.

• Food Science and Preservation
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• v.15 no.3
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• pp.377-384
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• 2008

The gamma irradiation process was performed to prolong a shelf-life of peaches and the effects of a gamma irradiation on the nutritional, physiochemical and sensory characteristics of peaches were evaluated during a post-irradiation storage at $4^{\circ}C$ and $25^{\circ}C$. Nutritional, physiochemical and sensory characteristics of peaches were stable at 1 kGy of an irradiation, a recommended dose for fruits and vegetables by CODEX, and the viable cell counts of contaminated microorganisms were reduced by 2 decimal reduction, at this dose. After a 1-week storage at ambient condition, the microbiological quality of the 1 kGy irradiated peach was stable, while all the non-irradiated peaches were deteriorated Furthermore, cold storage enhanced the shelf-life of the gamma irradiated peach and the nutritional and physiochemical characteristics of the peaches were comparatively stable up to 6 weeks. Right after gamma irradiation, the sensory evaluation results were not different in any of the samples, and the sensory quality of the irradiated peaches was adequate for a 4-week storage at $4^{\circ}C$. Our results suggested that gamma irradiation at 1 kGy can be used to enhance the shelf-life of peach without a significant loss in the quality attributes, especially upon cold storage after radiation treatment.