• Journal of Biosystems Engineering
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• v.32 no.2 s.121
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• pp.102-108
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• 2007

Heat pump systems are recognized to be heating and cooing systems. In this study, to check the practical application possibility of heat pump systems as low temperature storage systems and get basic data, apples of a long term storage items were stored and performance of low temperature storage and quality changes of apples were evaluated. Cooling coefficient of performance of the system was from 1.1 to 1.3. Although ambient air temperature varied widely from $-13^{\circ}C$ to $29.6^{\circ}C$ during low temperature storage period from January to June, the average temperature of low temperature storage chamber was $1.1^{\circ}C$ at setting temperature of $1.5^{\circ}C$. Sucrose of apples stored by the heat pump decreased from initial sucrose of 15.4% (Brix number) to final sucrose of 14.3%. Weight loss ratio of apples was 9.7% and internal and external view of apples after low temperature storage were very satisfactory with the naked eye.

• Korean Journal of Food Science and Technology
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• v.24 no.5
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• pp.515-518
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• 1992

In order to find a critical temperature for keeping the quality of Chang-pyung yeot (one of the Korean traditional taffy-like rice foods), a sensory evaluation and a puncture test were done, and the changes in the appearance of cross section and the surface color were investigated for 10 day's storage. There was no change of quality at storage temperature below $10^{\circ}C$, but at storage temperature above $15^{\circ}C$, the quality of Chang-pyung yeot deteriorated with storage time. After storage for 1 week at temperature above $15^{\circ}C$, they sticked each other as results of structure deformation and melting, and sticked to teeth In mouth resulting in an offensive feeling. The estimated critical storage temperature of Chang-pyung yeot was $12{\sim}13^{\circ}C$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.11
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• pp.1366-1372
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• 2017

This study compared the physicochemical quality characteristics of the Omija beverage for 36 weeks (9 months) depending on the storage container and storage temperature. From 3 weeks of storage, the optical density showed a significant difference according to the storage container, and the soluble solid contents showed a significant difference according to the storage container, storage temperature, and storage container${\times}$temperature. The total polyphenol and total acidity decreased slightly in the late storage period at all transparent and brown bottle treatments but the pH increased slightly. Generally, changes in the quality characteristics of Omija beverage at $4^{\circ}C$ storage were less than that at $20^{\circ}C$ and $36^{\circ}C$ storage. Correlation analysis of each factors, optical density, soluble solid content, total polyphenol, pH, and total acidity showed a positive correlation with each item according to the storage period. The storage period, particularly the transparent bottle treatment, appeared to have a significant impact on reducing the optical density. A few quality changes were observed after the brown bottle treatment for 36 weeks. In addition the stability according to the storage temperature was confirmed in each treatment. The brown bottle treatment is effective in maintaining the quality of Omija beverage for 36 weeks.

• The Korean Journal of Food And Nutrition
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• v.30 no.4
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• pp.681-688
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• 2017

This study was conducted to investigate the effect of gelatin concentration and storage on color and texture of puffer fish stock jelly. Puffer fish stock jelly was prepared by adding various amounts (2.5~10 percent) of gelatin to puffer fish stock. Color changes of puffer fish sstock jelly were also investigated during storage at $4^{\circ}C$ and $25^{\circ}C$ with varying amount of gelatin (2.5~10.0 percent). Regardless of storage temperature, the L values of puffer fish stock jelly were slightly increased, while a values of the stock jelly were negatively decreased during storage. However, L and negative b values were decreased with increasing gelatin concentration, whereas a values were increased negatively with increasing gelatin concentration. The texture profiles of puffer fish stock jelly such as hardness, springiness, cohesiveness adhesiveness, chewiness and brittleness were determined during storage at $25^{\circ}C$ and $4^{\circ}C$ at various intervals. The hardness, chewiness and brittleness were increased during storage at $25^{\circ}C$ for four days, while those of springiness and cohesiveness were decreased during storage. However, the values of all textural parameters were increased with increasing gelatin concentration in puffer fish stock jelly. Patterns of textural parameters of puffer fish stock jelly stored at $4^{\circ}C$ were practically identical to those stored at $25^{\circ}C$.

• Korean Journal of Plant Resources
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• v.27 no.1
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• pp.72-79
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• 2014

This study was investigated the changes in quality of peeled chestnut according to peeling method, including abrasion and knife, and 3 kinds of storage temperatures. The weight loss rate of peeled chestnut during storage period was observed in all treatment groups, peeling methods showed no difference of the loss. However, the moisture content of peeled chestnut during storage in all treatments showed a tendency to decrease. Moisture content of the abrasion peeled chestnut in all treatments was higher than that of the knife peeled chestnut. In the case of a, b, and ${\Delta}E$ value of peeled chestnut chromaticity increased during storage in all treatments, whereas, L values decreased during storage. But, browning of abrasion peeled chestnut was higher than that of the knife peeled chestnut. The hardness of the abrasion and knife peeled chestnuts were the highest in $-1^{\circ}C$ storage, soluble solid content was decreased with storage time in all treatments, but showed a tendency to increase within 24 days. Palatability and texture of peeled chestnuts decreased in all treatments during storage period, 15 days after storage decreased rapidly. Thus, results showed that peeled chestnuts stored at $4^{\circ}C$ and $2^{\circ}C$ were rapidly decreased in the quality after 15 days, whereas, peeled chestnuts stored at $-1^{\circ}C$ slowly decrease in the fruit quality. It can be recommended that chestnut in vacuum film is good to maintain at $-1^{\circ}C$ storage for 15 days. Also, if we can reduce the browning of abrasion peeled chestnut, we will produce peeled chestnut of high quality.

• Food Science and Preservation
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• v.17 no.2
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• pp.230-235
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• 2010

We investigated the physicochemical quality characteristics of apple juice upon sterilization using hot water, and under various storage conditions. None of sugar content, acidity, or pH differed significantly among various sterilization conditions but chromaticity was considerably reduced in sterilized juice compared with control material. The chromaticity of non-sterilized juice decreased significantly after sterilization compared with material supplemented with vitamin C (0.1%, w/v). Fungi, yeast, and aerobic bacteria were detected in juice sterilized at $65^{\circ}C$ for 10 or 20 min, but no microorganisms were observed in juice sterilized by other procedures. Vitamin C content affected sterilization temperature to a greater extent than sterilization time. When juice was stored at $4^{\circ}C$ or $37^{\circ}C$ for 3 weeks after application of different sterilization conditions, almost no change in acidity, sugar content, or pH was observed, regardless of sterilization mode or storage period. However, chromaticity decreased with longer storage. Vitamin C levels were reduced by higher sterilization temperatures. However, longer storage periods had the greatest effect on reduction of vitamin C levels, which tended toward lower values regardless of differences in sterilization and storage conditions. In sensory evaluation tests, all of taste, color, and overall preference were highest for juice sterilized at $75^{\circ}C$ for 20 min. The ASC value was low at a storage temperature of $4^{\circ}C$ and at high sterilization temperatures, and a long storage period was associated with a greater ASC value. Thus, the quality of apple juice was excellent when juice was hot water-sterilized, with additional vitamin C, at $75^{\circ}C$ for 20 min, followed by storage at $4^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.8 no.2
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• pp.74-79
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• 1976

Two rice varieties in Korea, an Indica type 'Tongil' and a Japonica type 'Jinheung', were stored at $5^{\circ}C$ and $30^{\circ}C$ for six months and the changes in organoleptic quality and lipid components were investigated to obtain the following results. In storage, both varieties brought about increases of hardness, cohesiveness and gumminess, and a decrease of adhesiveness among textural parameters of cooked rice. Storage at $5^{\circ}C$ showed no change in organoleptic quality but storage at $30^{\circ}C$ caused the occurrence of off-flavor in both varieties and a marked decrease of stickiness in Jinheung. Rice samples before storage contained 5-times more free lipids than bound lipids and free lipid content of Tongil was $70{\sim}80%$ of Jinheung. In storage, bound lipids tended to increase slowly while free lipids increased in both varieties at $5^{\circ}C$ and tended to increase in Tongil and to decrease in Jinheung at $30^{\circ}C$. In free lipid fractions of rice samples before storage were found 9 components including triglycerides, free fatty acids and sterol esters and in bound lipid fractions were found 8 components including free fatty acids and sterol esters, as the major components. In storage, changes in lipid components were more remarkable in free lipids than in bound lipids and in Jinheung than in Tongil. It was, therefore, concluded that Tongil variety had a better storage stability than Jinheung variety and the deterioration of rice quality occurred mainly in free lipid fractions during storage.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.9 no.2
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• pp.129-142
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• 1976

Optimum doses The optimum dose that may be defined as the dose below the maximum permissible dose, yet would bring about a significant storage life extension at refrigerated temperatures, varied with species of fish as well as with the postirradiation storage temperatures. Thus the dose of 0. 1 Mrad was considered to be optimum for the croaker and yellow corvenia at $0^{\circ}C$, while at $5^{\circ}C$ the dose of 0.2 Mrad would be suitable for both species. The roundnose flounder was more radiosensitive and even at the dose of 0.1 Mrad a slight irradiation odor was detected immediately after the radiation treatment. Such degree of irradiation odor disappeared upon storage, therefore, the dose of 0.1 Mrad was considered to be optimum for the roundnose flounder at both $0^{\circ}\;and\;5^{\circ}C$. Storage life extension The croaker meats irradiated at 0.1 Mrad could be held at $0^{\circ}C$ as long as 5 weeks in good acceptable conditions, while the unirradiated control became unacceptable within 2 weeks-3-4 for extension of storage life at $0^{\circ}C$. At the storage temperature of $5^{\circ}C$, the storage life of 0.2 Mrad irradiated samples was extended from less than one week to 4 weeks--4-5 fold extension. The storage life extension of 0.1 Mrad irradiated yellow corvenia at $0^{\circ}C$ was from less than 2 weeks for the unirradiated to 4 weeks-approximately a-s folds and that of 0.2 Mrad irradiated samples stored at $5^{\circ}C$ was from 5 days to 3 weeks 4-5 folds. The roundnose flounder meats irradiated at 0.1 Mrad could held at $0^{\circ}C$ for 3-4 weeks as compared to less than 1 week for the unirradiated and at $5^{\circ}C$ the storage life could be extended from less than 3 days to up to 3 weeks. Thus the storage life extension by 4-5 folds and by 6-7 folds was possible at $0^{\circ}C\;and\;5^{\circ}C$ storage, respectively. Postirradiation storage microbiology and biochemistry In general 10 fold reduction of initial microflora was realized as a result of irradiating fish samples at 0.1 Mrad. The extent of microflora reduction increased with increasing doses applied, but not proportionately dependent. The microbial growth in the irradiated was severely retarded during the subsequent storage period, lagging far behind that of the irradiated control samples except in the late storage phase, when the levels of microflora of the irradiated either approached to or rose above the levels of the unirradiated. The microbiological changes caused by irradiation was reflected in the pronounced suppression of TVB and TMA accumulation during the storage period. This suggests that irradiation treatment brought about both quantitative and qualitative changes in microflora initially present and it is reasonable to suggest that the microflora removed by irradiation in fact represent most of the flora capable of producing TVB and TMA in normal fish spoilage process.

• Korean Journal of Food Science and Technology
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• v.28 no.1
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• pp.8-14
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• 1996

The effects of temperature variations during storage, pasteurization on the quality of orange juices were investigated. To evaluate the quality of orange juices pasteurized at 75, 85 and $95^{\circ}C$ for 15 sec, microbial and physicochemical measurements and sensory evaluations were conducted during storage at 10, 20 and $30^{\circ}C$ for 32days. Color(lightness) and contents of vitamin C and sucrose were not changed at $10^{\circ}C$, but decreased at $20^{\circ}C$ and $30^{\circ}C$ as the storage time was increased. The pasteurization temperature had a little effect on the color and the contents of vitamin C and sucrose. Furfural contents were apparently increased as the storage period extended, but the samples stored at $10^{\circ}C$ had less amounts than the others. On the other hand, the pasteurization temperature did not affect furfural accumulation. Furfural was produced as a result of the degradation of vitamin C and deterioration of the color. The PH values were not changed during the entire storage period, and microorganisms were not detected in most of the samples. The result of sensory evaluation indicated no taste difference between the control and the sample stored at $10^{\circ}C$, but the taste changes were recognized when the samples were stored over 24 and 20 days at $20^{\circ}C$ and $30^{\circ}C$, respectively. Therefore, the storage temperature affected the quality of orange juices more markedly than the pasteurization temperature, and the storage at lower temperature appears to reduce the deterioration of orange juices.

• Journal of Bio-Environment Control
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• v.21 no.4
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• pp.404-410
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• 2012

This study was conducted to examine effects of harvest time (09:00 vs. 14:00), precooling at $4^{\circ}C$ vs. no precooling, and storage temperature (4 vs. $8^{\circ}C$) on the storage life of 'Maehyang' strawberry fruits for export. Fruits at a 60% ripe stage were harvested from a commercial greenhouse in Gyeongsangnamdo, Jinju on May 4, 2010. Fruits were precooled by a forced draft cooling for three hours, transported for about 30 minutes and then stored, immediately. Small precoolers set in the farm were used for precooling. Fruits were placed in constant temperature chamber (4 or $8^{\circ}C$) after packaging using PVC wrap and a cardboard box. Fruits were examined for their changes in weight, hardness, Hunter color values, soluble solids content (SSC), and incidence of gray mold (Botrytis cinerea) during storage at a two days interval from May 6 to May 14, 2010. Hardness and SSC decreased as the ripening stage progressed. The Hunter's 'L' and 'a' value of fruit color decreased as time passed. Also, fresh weight decreased during storage at all temperatures. Soft rot appeared on epidermal tissues and followed by gray mold. Incidence of gray mold was greater at $8^{\circ}C$ storage temperature than in $4^{\circ}C$ storage temperature. However, no difference by the harvested time and precooling. The results indicate that effectiveness for keeping the freshness was best achieved by precooling at $4^{\circ}C$ and storage at $4^{\circ}C$, respectively.