• The Korean Journal of Food And Nutrition
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• v.9 no.4
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• pp.478-483
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• 1996

We investigated the changes of composition in immature green persimmon during cold(7$^{\circ}C$) and freezing (-2$0^{\circ}C$) storage for 30 days. Moisture, protein, fat and carbohydrate were not significantly different by storage temperature and storage days. Crude fiber had little change during freezing storage, but in case of cold storage, as storage time goes by, it slightly deceased. Content of polyphenol was increased during cold and freezing storage, especially during cold storage it was remarkably increased. Content of total pectin was decreased, while content of soluble pectin was increased during cold storage. Content of total pectin and soluble pectin was slightly decreased or increased during freeze storage. Content of tannin had little change during freezing storage but it significantly decreased during cold storage.

• Korean Journal of Food Science and Technology
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• v.39 no.6
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• pp.663-668
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• 2007

This study evaluated the microbial, nutritional, and rheological changes in potatoes, during storage at room, low, and freezing temperatures for 6 months. No significant changes in total aerobic plate counts were observed for any of the samples in the assessment of microbiological quality changes. For the 4 types of frozen potatoes, yeasts and molds were not found until 24 weeks. The sugar contents of the potatoes stored at room and low temperature ($10^{\circ}C$) increased during the first 4 weeks of storage, but then decreased rapidly thereafter; while those in the frozen potatoes did not change significantly throughout the 48 weeks. The vitamin C, B1, and B2 contents of the potatoes stored at room and low temperature had decreased significantly after 4 weeks of storage, however, the levels in the frozen potatoes did not change rapidly. The weight, volume, and hardness of the frozen potatoes changed much less as compared to the potatoes stored at room and low temperature over the 48 weeks of storage. Finally, the cohesiveness of all the samples, except for the frozen mashed potatoes, did not change during storage.

• Korean Journal of Food Science and Technology
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• v.27 no.4
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• pp.520-524
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• 1995

ATP related compounds, ammonia, VBN, pH and sensory quality of shrimps were determined to evaluate quality changes during iced and frozen storage. ATP related compounds were determined by HPLC, ammonia by ammonia ion specific electrode, VBN by micro-diffusion method, pH by pH meter, sensory quality by multiple comparison test with 30 panelists. K value of ice stored shrimps gradually increased to 20% for 8 days, and then increased more rapidly, whereas that of frozen stored shrimps increased slowly for 7 months. Ammonia contents in ice stored shrimps increased slowly for 6 days and then rapidly after 8 days storage, whereas that in frozen stored shrimps increased slowly for 8 months. VBN contents in ice stored shrimps increased slowly for 10 days and then rapidly after 12 days. VBN contents in frozen stored shrimps slightly increased for 6 months. Sensory scores of taste and color of shrimps marked lowered values after 6 days storage in ice, and after 6 and 7 months frozen storage, respectively. Sensory flavor scores of stored shrimps had significant correlations with K value, ammonia, pH and VBN. These results indicated that ammonia contents in stored shrimps, rapidly determined by an ammonia electrode, could be used as a quality index of shrimps.

• Food Science and Preservation
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• v.24 no.6
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• pp.746-757
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• 2017

This study was performed to evaluate the effect of different freezing conditions and storage periods on physicochemical and microbial characteristics of garlic. Garlics were washed, dried, sliced to 0.3 cm then packed in LDPE+LLDPE film bags. They were treated with still-air freezing at $-20^{\circ}C$ (SAF20), $-40^{\circ}C$ (SAF40) and immersed-liquid freezing at $-40^{\circ}C$ (ILF40). Frozen garlics were stored under frozen storage conditions for 7 months at $-20^{\circ}C$ and quality characteristics were measured monthly during the frozen storage. Freezing rate of garlic was the fastest in ILF 40 (10 min), SAF40 (40 min) and SAF20 (1,600 min) sequentially. In ILF40, drip loss, cutting force, total aerobic bacteria count and pH were the lowest, whereas pyruvic acid and allicin content were the highest (p<0.05) during frozen storage, these results were the most similar characteristics with the fresh garlic. During frozen storage, drip loss, color difference and total organic acid content were significantly fluctuated in SAF20 (p<0.05), while they were not changed in ILF40. Overall, total aerobic bacteria count and pH decreased, cutting force, pyruvic acid and allicin content remained unchanged in all groups. In conclusion, the optimal freezing conditions for garlic with the least quality changes was considered to be ILF40 (immersed liquid freezing), keeping quality characteristics up to 7 months by freezing storage.

• Korean journal of applied entomology
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• v.39 no.3
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• pp.149-152
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• 2000

Cryopreservation of infective juveniles of entomopathogenic nematode, Steinernema carpocapsae Weiser, was conducted at $-190^{\circ}C$ liquid nitrogen and its, efficacy was analysed on nematode survival and pathogenicity with glycerol pretreatments and storage periods. Infective juveniles were pre-treated before being frozen by incubating the nematodes in 22% glycerol for each of 6, 12, and 24 h, followed by 70% methanol at $0^{\circ}C$ for 10 minutes. Just after glycerol and methanol incubations, subsamp1es of the nematodes were resuspended in 0.85% saline and maintained during 24h for viability determination. Different glycerol incubation periods significantly affected the nematode susceptibility to methanol infiltration. Six hour incubation in glycerol resulted in much less nematode survival than did 12 h or 24 h incubation. About 70% of the infective juveniles frozen at $-190^{\circ}C$ for 5 months, preincubat-ed in glycerol at least for 12h, were able to survive after being resuspended in 30°C saline. They did not also show any change in their pathogenicity during cryopreservation. These results suggest an improved technique for long-term storage of the entomopathogenic nematodes.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.33 no.7
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• pp.26-32
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• 2004

식품을 상온에 두면 내부에서 일어나는 생물화학적 반응이나 미생물의 증식 등으로 효소적, 미생물적 변질, 변패 등의 손상을 입고 마지막에는 부패되어 불가식품의 상태에 이르게 된다. 인류는 이러한 식품의 품질저하를 방지하기 위하여 고금을 통하여 많은 저장방법을 연구하여 왔다. 그 방법의 하나로 식품을 저온에 저장하는 냉동 저장법이 있으며 이 방법은 식품저장법중 가장 우수하고 현대적인 방법이다. 냉동 저장법이 식품에 응용되기 시작하면서 각국에서는 시장 유통 단계에서 필요한 기술을 도입하여 냉동 식품에 관한 제반 시설의 건설 설비 및 보급이 증가 추세에 있다. 또, 냉동은 식품 저장을 위한 수단 외에 가공 수단으로서 신가공 식품 제조, 동결 건조(freeze drying) 및 동결 저장 기술 등에 적용되기도 한다. 여기서는 농식품분야에 있어서 냉동기술의 적용 사례와 새로운 기술들을 소개하고자 한다. (중략)

• Korean Journal of Food Science and Technology
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• v.34 no.3
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• pp.413-418
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• 2002

The dough was frozen either before or after fermentation at the five different freezing and storage conditions. Although fermentation before freezing was effective for rapid freezing, it reduced bread volume of the dough frozen at both air freezer and liquid immersion freezer. Freezing at the air freezer set to $-70^{\circ}C$ took more time for freezing and resulted in lower bread volume than freezing at the immersion freezer set to $-20^{\circ}C$. Therefore, the freezing in the liquid immersion freezer was more effective to reduce the freezing time and increase the bread volume. At the liquid immersion freezer, the higher temperature was more effective than lower temperature. The doughs frozen in a liquid immersion freezer set to $-10^{\circ}C$ and fermented after de-frosting produced higher bread volume than control unfrozen dough. And also there was no significant difference in bread volume between the control unfrozen dough and the dough frozen in a liquid immersion freezer set to $-10^{\circ}C$, fermented before freezing and re-fermented after defrosting. The longer proof time and greater loaf volume obtained for the dough frozen and stored at the air freezer set to $-70^{\circ}C$. Therefore the optimum process for freezing the dough was freezing immediately after mixing, storing at $-10^{\circ}C$ in a liquid immersion freezer and fermented after defrosting.

• Korean Journal of Food Science and Technology
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• v.23 no.4
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• pp.389-393
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• 1991

The changes in Physical properties of egg yolk(refractive index 43) as affected by salt content(7%, 10%, 13%) during frozen storage and their effects on functionalities in mayonnaise preparation were investigated. As the frozen storage period of salted egg yolk increased, viscosity was increased, and further increased with higher salt content, and emulsification capacity was gradually decreased. In case of egg folk with 7% salt, emulsification capacity was considerably decreased during the storage at $-25^{\circ}C$ over 4 months. Microbes of salted egg yolk were decreased with frozen storage, but the difference was not due to salt content. Mayonnaise. Prepared with frozen egg yolks stored for $2{\sim}3$ months, maintained a minimum viscosity. Viscosity became higher in the mayonnaise which prepared with egg yolk of higher salt content stored at $-25^{\circ}C$. Oil particle size of mayonnaise with the yolk contained more salt was smaller, when the yolk was stored at $-25^{\circ}C$ than $-15^{\circ}C$. Noticible microbes were detected in the mayonnaise right after preparation, but not detected in the mayonnaise after 1 month storage.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2005.10a
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• pp.263-266
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• 2005

닭고기의 신선도를 측정하기 위하여 HPLC를 이용한 핵산관련물질의 상호관계를 분석하여 계산된 K 값과 휴대용 Torry meter 값과의 상관관계를 측정하여, 닭고기 등급판정 현장에서 휴대용 Torry meter의 이용 가능성을 제고하기위하여 실시하였다. 닭고기 냉동육의 피부를 포함한 가슴 부위를 측정하였을 경우 저장 20일까지는 일정하게 저하되었으나, 30일에서는 오히려 증가하는 경향을 나타냈다. 이러한 경향은 피부를 제거시켰을 때는 더욱 심하여 저장 5일까지 감소하다 저장 10일에서는 증가하는 경향을 보여 일정한 경향을 나타내지 않았다. K값에서도 저장기간이 증가하면 약간씩 증가하는 경향은 보였으나 저장기간에 따라 변화가 심하였다. Torry meter에 의한 닭고기 신선도 측정은 냉장육에서는 이용 가능성이 보이나 냉동육에서는 저장일시에 따라 변화가 심하고 일정한 경향을 보이지 않아 이용 가능성 낮은 것으로 판단되나 수입육이 6개월 이상 냉동상태에서 수입된다고 볼 때 장기적 냉동시험이 필요하다고 사료된다.

• Food Science and Preservation
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• v.23 no.3
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• pp.445-452
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• 2016

In this study, physicochemical properties of acorn flour was investigated, and characteristics of the Jeung-pyun dough added with the acorn flour at various concentrations were evaluated after storage at -$18^{\circ}C$ for 4 weeks and fermentation. Total polyphenolic content, electron donating ability (EDA) of 0.5%, gelatinization onset temperature (To), gelatinization peak temperature (Tp), and gelatinization conclusion temperature (Tc) of acorn flour were 3,525.12 mg%, 16.71%, $68.41^{\circ}C$, $73.83^{\circ}C$, and $82.96^{\circ}C$, respectively. These all values were increased in the Jeung-pyun dough possibly due to addition of the acorn flour. The yeast count was not affected by the addition levels of acorn flour and the frozen storage period before fermentation. The amount of carbon dioxide gas evolved from Jeung-pyun dough during fermentation was significantly changed with the concentration of acorn flour, but it was negligible. The Jeung-pyun added with 6% acorn flour showed an small increase in the amount of carbon dioxide after frozen storage of 1 wk and fermentation. The pH of the fermented Jeung-pyun samples decreased along with the increasing storage period as well as the increasing acorn flour content, ranging from 4.21 to 5.34. Therefore, the frozen Jeung-pyun dough containing 6~15% of acorn flour and stored for 3 weeks was the most desirable among all the tested samples in this study.