• Korean Journal of Agricultural Science
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• v.43 no.3
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• pp.340-345
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• 2016

The kiwi fruit (Actinidia deliciosa cv. 'Hayward') should be ripened at any step during postharvest handling before consumer consumption. This is essential for freshly harvested kiwi fruit. But, this requires correct temperatures and ethylene concentrations. More testing of a newly developed ethylene generator using charcoal for commercial purposes is needed. This study was conducted to investigate the optimum storage temperatures and the effect of ethylene on the postharvest quality of kiwi fruit. Three different ethylene concentrations of 10, 50, and $100{\mu}L{\cdot}L^{-1}$ were used on fresh kiwi fruit stored at different temperatures of 10, 15, and $20^{\circ}C$. The quality changes of the fruits were assessed by sensory evaluation and by measuring firmness, soluble solids content, titratable acidity, and ethylene production. Higher storage temperatures and ethylene concentrations softened the kiwi fruit quickly and led to the rapid loss of acidity while soluble solid contents of fruit increased to a significant extent during the same storage period. Similarly, the firmness of ethylene-treated fruits stored at 20 and $15^{\circ}C$ dramatically decreased in the experiment while treated fruits stored at $10^{\circ}C$ decreased only slightly. Quality characteristics of kiwi fruits stored at 15 and $20^{\circ}C$ were better than those of fruits at $10^{\circ}C$. With regards to the effect of temperature, fruits stored at lower temperatures took a longer time to ripen and retained their quality longer. The newly developed ethylene generator maintained the ethylene concentration in the 5 kg box at $40-400{\mu}L{\cdot}L^{-1}$. The ethylene generator could also be used to soften persimmons.

• Journal of Mushroom
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• v.18 no.1
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• pp.115-119
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• 2020

This study was conducted to investigate the effect of post-harvest CO₂ treatment on the quality of the 'Gonji-7ho' oyster mushroom. The harvested mushrooms were pre-cooled at 3℃ for 1 day and placed in a gas-tight chamber with 0%, 30%, or 50% of CO₂ concentration for 3 hours at 3℃. Next, 400 g of the oyster mushroom sample was packaged into 20-㎛ thick oriented polypropylene (OPP) film bags and stored at 4℃ for 21 days. Treatment with 30% of CO₂ treatment maintained the highest stipe firmness of the oyster mushrooms during storage. The stipe lightness (CIE L^⁎) was the highest at 14 and 21 days, while the stipe yellowness (CIE b^⁎) was the lowest at 2 and 7 days of storage. Therefore, we concluded that the 30% CO₂ treatment maintained the overall visual quality of the 'Gonji-7ho' oyster mushroom until 17 days of storage at 3℃. Our results suggest that the shelf life of 'Gonji-7ho' oyster mushroom could be extended by the postharvest application of 30% CO₂ for 3 hours during low temperature storage.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 1995.12a
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• pp.7-8
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• 1995

• Food Science and Preservation
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• v.23 no.5
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• pp.623-630
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• 2016

Inappropriate storage of fresh-cut onions may result in losses of good quality. To understand storage conditions for shelf-life and quality of fresh-cut onions, The effect of packing type and storage temperature on the quality of fresh-cut onions was evaluated. Onions stored at $0^{\circ}C$ for 2 months were peeled off after removing root and shoot parts. Each three peeled onions were packed in a polyethylene film (PE, $50{\mu}m$) or in a polyethylene/polypropylene film (PE/PP, $100{\mu}m$) with vacuum treatment (70 cmHg) and stored at different temperatures (4, and $10^{\circ}C$) for 21 days. The following analyses were examined to evaluate the quality of fresh-cut onions: microbial population, surface color, titratable acidity and pH, respiration rate, and sensory quality. Fresh-cut onions stored at $4^{\circ}C$ showed less aerobic and coliform bacterial population than those stored at $10^{\circ}C$ during observation periods. Fungal populations of fresh-cut onions packed in PE film stored at $10^{\circ}C$ increased significantly after 13 days. E. coli was not detected in all treatments during whole storage periods. Surface colors of fresh-cut onions were not affected by packing type and storage temperature, however, color difference (${\Delta}E$) of fresh-cut onions in PE/PP film stored at $10^{\circ}C$ was significantly higher than those of other treatments. Titratable acidity of fresh-cut onions was not affected by packing type and storage temperature. However, pH of fresh-cut onions packed in PE film stored at $10^{\circ}C$ increased gradually over the whole storage period. Fresh-cut onions packed in PE film showed higher $CO_2$ and less $O_2$ concentrations at $10^{\circ}C$ than those at $4^{\circ}C$. The sensory quality of fresh-cut onions was significantly affected by packing type and storage temperature after 13 days. Particularly, vacuum treatment in PE/PP film showed better sensory quality than that of PE film package at the same storage temperature. It was concluded that vacuum treatment and storage at $4^{\circ}C$ could be effective to prolong the quality of fresh-cut onions up to 21 days.

• Food Science and Preservation
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• v.21 no.5
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• pp.601-608
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• 2014

To determine the optimal shelf life for maintaining the high quality of kohlrabi, the changes in the physiological and secondary metabolites of kohlrabi stems during storage were investigated. The results showed that the kohlrabi maintained its marketable quality for two weeks at room temperature and for two months in cold storage ($4^{\circ}C$). Interestingly, the total phenol and flavonoid contents sharply declined along with the quality deterioration after two-week storage at room temperature. Moreover, insignificant changes in these compounds were observed for two months during the cold storage. The secondary metabolites of the kohlrabi were also influenced by its storage condition. The total phenol and total flavonoid contents of the kohlrabi significantly increased with the storage periods at low temperature, and significantly decreased with the storage periods at room temperature. In terms of the packaging, no significant difference in the total phenol content of the kohlrabi was found between the packaged and non-packaged types of storage. However, the flavonoid content of the packaged kohlrabi was higher than that of the non-packaged kohlrabi at the end of their storage. The content of glucosinolates, an anti-cancer ingredient was maintained during the storage, so the vegetables remained good sources of these compounds when stored in cold storage even for a long period. This study showed a close correlation between the secondary metabolites and the change in the quality of kohlrabi during storage. The results also suggested that secondary metabolites such as phenolics can be considered quality indicators of the shelf life of kohlrabi.

• Food Science and Preservation
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• v.31 no.3
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• pp.433-443
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• 2024

This study investigated the effect of packaging method and root trimming on quality of green onions during storage. Two packaging methods (tied with string, S or packaged with film bag, FP) and two root trimming states (attaching the roots without trimming, AR or cutting the roots leaving about 5 mm, CR) were treated after harvest. Then, the green onions stored at 20℃ for 8 days and 1℃ for 6 weeks to investigate changes in quality. When stored at 20℃, the differences in marketability between S and FP were minimal, while when stored at 1℃, the marketability of the FP remained higher than that of S. The leaf color change in CR progressed faster than in the AR treatment group, leading to faster quality deterioration. The occurrence of weight loss, browning, and softening of stems progressed as the storage period elapsed. However, except weight loss, they were at a level that did not affect marketability within the marketability limit period determined by color change and wiltig of leaves. The allicin and quercetin contents of stems increased in the early stages when quality deteriorated after harvest but decreased as quality deterioration became more severe.

• Food Science and Preservation
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• v.30 no.5
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• pp.822-832
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• 2023

This study investigates the effectiveness of CA (controlled atmosphere) containers in maintaining the freshness of exported melons. The melons were harvested on June 5, 2023, in the Yeongam area of Jeollanam-do, Korea. The CA container was loaded with melon samples packed in an export box. The temperature inside the container was set at 4℃, while the gas composition was set at 5% oxygen, 12% carbon dioxide, and 83% nintrogen. Following two weeks of simulated transportation, quality analysis was conducted at 10℃. The melons were inoculated with spore suspensions, and the decay rate was determined to investigate the effect of the gas composition inside the CA container on suppressing the occurrence of Penicillium oxalicum in melons. The results were compared with a Reefer container set at the same temperature. The samples transported in the CA container exhibited lower weight loss. The melon pulp softening, respiration rate, and ethylene production were slower using the CA container. Moreover, the decay rate during the distribution period in the CA container was lower than in the Reefer container. In contrast, the firmness of melons transported in the Reefer container decreased significantly (from 9.03N to 5.18N) immediately after transportation. The soluble solid content (SSC) of melons transported in the Reefer container also decreased rapidly. The results suggested that the CA container is the optimal export container for maintaining the freshness of melons.

• Journal of Biosystems Engineering
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• v.39 no.3
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• pp.194-204
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• 2014

Purpose: The aim of this study was to develop long-term storage technology for Chinese cabbage in order to extend the period of availability of freshly harvested products. The scope of the paper deals with the use of a cooler with a remote monitoring and control interface in conjunction with use of packaging film. Methods: A cooler with a real time monitoring system was designed as a low-temperature storage facility to control temperature and relative humidity (RH). The effects of storage in high-density polyethylene (HDPE) plastic boxes, 3% chitosan dipping solution, polypropylene film (PEF) with perforations, and mesh packaging bags on physiological responses were investigated. The optimal storage temperature and humidity for 120 days were below $0.5^{\circ}C$ and 90%, respectively. Physiological and biochemical features of cabbage quality were also analyzed: weight loss, texture, and sugar salinity, chlorophyll, reducing sugar, and vitamin C contents. Results: The cooler with a remote monitoring and control interface could be operated by an HMI program. A $0.5^{\circ}C$ temperature and 90% humidity could be remotely controlled within the cooler for 120 days. Postharvest freshness of Chinese cabbages could be maintained up to 120 days depending on the packaging method and operation of the remote monitoring system. In particular, wrapping the cabbages in PEF with perforations resulted in a less than a 5% deterioration in quality. This study provides evidence for efficient performance of plastic films in minimizing post-harvest deterioration and maintaining overall quality of cabbages stored under precise low-temperature conditions with remote monitoring and a control interface. Conclusions: Packaging with a modified plastic film and storage in a precisely controlled cooler with a remote monitoring and control interface could slow down the physiological factors that cause adverse quality changes and thereby increase the shelf life of Chinese cabbage.

• Journal of Mushroom
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• v.19 no.3
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• pp.234-245
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• 2021

To extend the shelf life of king oyster mushrooms for export, we investigated the impacts of mushroom quality grade, fruiting body trimming, and packaging method (tray container sealed packaging vs string-tied OPP bag packaging). Quality is divided into two grades: 1^st grade, which is mushrooms adapted by lowering the cultivation temperature to 9~11℃, and 2^nd grade, mushrooms held at 13~15℃ prior to harvest. Using selected 1^st and 2^nd grade mushrooms, 3 treatments were carried out to assess effects of trimming and packaging method. Test groups included 1) trimming plus string-tied OPP bag packaging (Cut & OPP), 2) no trimming plus string-tied OPP bag packaging (Uncut & OPP), and 3) trimming plus tray container sealing packaging (Cut & Tray). Gas composition inside the packaging, changes in quality factors, and sensory evaluation for fresh quality were performed over 42 days of 0℃ storage. Overall freshness was best maintained in the following order: Cut & Tray > Cut & OPP > Uncut & OPP for both 1^st and 2^nd grade mushrooms. The shelf-life of 1st grade mushrooms was about 30 days for Cut & Tray, 28 days for Cut & OPP, and 21 days for Uncut & OPP. The shelf-life of 2^nd grade mushrooms was about 22 days for Cut & Tray, 17 ays for Cut & OPP, and 14 days for Uncut & OPP. Factors affecting fresh mushroom quality included browning of cap and stalk, and mushroom decay index. Browning of the lower part of the stalk, with related color change as noted in a^* and b^* values were the main factors indicating quality deterioration of king oyster mushrooms.

• Journal of Mushroom
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• v.20 no.3
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• pp.138-146
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• 2022

To optimize initial cooling conditions, forced-air cooling was applied to freshly harvested oak mushrooms at 2 levels (0℃ for 30 minutes, at 0℃ for 1 hour) followed by room cooling at 3 levels (-3℃ for 1 day, 0℃ for 1 day, 3℃ for 1 day). After initial cooling, the oak mushrooms were packaged with PVC film, then held in a storage room at 1℃ for 6 weeks. Quality characteristics and percentage marketability were then investigated. As a control, Mushrooms were placed in storage with no initial cooling. The quality factors impacting marketability of fresh oak mushrooms were color change and appearance of decay. Off-odor did not occur or developed only slightly, so it did not affect oak mushroom quality within 6 weeks of low temperature storage. In all treatment groups, the shelf life in which 100% marketability was maintained was up to 3 weeks. At week 5, percent marketability of the 3 treatment groups 1 hour room cooling treatment at 0℃, 1 hour forced air cooling, and control was 100%. 80% In the group that underwent 30 min forced air cooling retained 80% marketability, and the group exposed to 1 day in room cooling at -3℃ retained 86.7% marketability. At week 6 of 1℃ storage, the marketability ratio was 80% in the 1 day room cooling at 0℃ group, 66.7% in the 1 day room cooling at 3℃ group, 46.7% in the 1 hour forced air cooling group, and 33% or less in all other treatment groups. Therefore, the most suitable initial cooling parameter to extend shelf-life of oak mushrooms is 1 day of in room cooling at 0℃ immediately after harvest.