• 한국식품조리과학회지
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• 제19권6호
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• pp.758-764
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• 2003

This study was performed to determine the quality characteristics of mixed polysaccharide gels made from kcarrageenan and locust bean gum with various kiwifruit content after freeze-thawing. The syneresis, rupture properties, TPA properties and sensory properties of the mixed polysaccharide gels with various kiwifruit contents after freeze-thawing were measured. The syneresis of the gel with various kiwifruit contents by freeze-thawing was not significantly different, whereas repeating freeze-thawing resulted in remarkable increase in the syneresis of the mixed polysaccharide gels with 5％, 20％ and 40％ kiwifruit. In terms of the rupture properties, the rupture stress, rupture energy and rupture strain decreased with increasing kiwifruit content after freeze-thawing. In terms of the TPA properties, the adhesiveness, hardness and chewiness increased and the cohesiveness decreased with increasing kiwifruit content after freeze-thawing. The rupture properties, springiness and cohesiveness of the gel by freeze-thawing were lower than those of the gel stored in the refrigerator. In contrast, the gumminess, hardness and chewiness of the gel after freeze-thawing were higher than those of the gel stored in the refrigerator. The results showed that the gel became crumbly and tough as a result of freeze-thawing. In the sensory evaluation, He overall acceptability of the gel after freeze-thawing was highest at the 30％ kiwifruit content, and differences in the sensory properties between the gel after freeze-thawing and that stored in the refrigerator were small. Therefore, mixed polysaccharide gels with kiwifruit after freeze-thawing could be useful despite the small decrease in quality.

• 대한토목학회논문집
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• 제32권1D호
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• pp.33-39
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• 2012

겨울철의 영하의 날씨와 잦은 눈으로 인해 도로 포장의 파손이 증가하고 있다. 본 연구에서는 도로 포장의 동결융해 메커니즘을 살펴보고, 다양한 평가 방법을 통해 배수성 아스팔트 포장의 동결융해 저항성을 평가하였다. 동결융해 저항성의 평가방법은 강성 포장과 연성 포장이 각각의 특성에 따라 다양한 평가 방법을 사용하고 있다. 본 연구에서는 변형률의 측정, 수정 로트만 실험, 반복 동결융해 실험, 표면 박리 저항성 실험과 같은 강성 포장과 연성 포장의 대표적인 동결융해 저항성 실험을 적용하여 평가를 실시하였다. 연구결과 배수성 아스팔트 콘크리트는 20%의 공극으로 인해 밀입도 아스팔트 콘크리트에 비해 온도에 따른 변형이 작은 것으로 평가되었다. 또한, 수분의 영향을 받는 동결융해 반복 실험에서도 수분의 원활한 배수와 수분의 동결 시 발생하는 팽창압을 분산시킬 수 있는 충분한 공극으로 인해 다른 종류의 아스팔트 혼합물에 비하여 동결 융해 저항성이 우수한 것으로 나타났다.

• 한국구조물진단유지관리공학회 논문집
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• 제13권6호통권58호
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• pp.126-134
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• 2009

일반적으로 철근콘크리트 건축물은 외부의 기후에 노출되어 있어 겨울에서 이른 봄까지 동결과 융해의 반복적인 작용에 영향을 받는다. 이러한 동결융해 작용은 콘크리트의 균열을 발생시키거나 콘크리트 표면의 박리를 일으켜 내구성 저하의 원인이 된다. 본 연구에서는 철근콘크리트 보의 동결융해 노출에 따른 휨 거동특성의 평가를 위해 주근비와 동결융해 사이클을 변수로 하였다. $-18{\sim}4^{\circ}C$의 온도범위에서 150 및 300 사이클의 동결융해에 노출시킨 실험체를 비롯하여 14개의 축소모형 실험체를 제작, 단조 및 반복하중 하에서 실험을 실시하였다. 실험결과를 통해 동결융해에 노출되어있는 철근콘크리트 보의 휨 거동특성을 평가하는데 기초적인 자료를 제시하고자 하였다.

• 한국식품영양학회지
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• 제34권3호
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• pp.263-271
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• 2021

Fresh Omija (Schisandra chinensis) has good marketability, but its quality is difficult to maintain during storage and distribution. Freezing and freeze-thawing treatments can be utilized for the quality maintenance and processing of cold press juice. In this study, the color, antioxidant properties, and the major components of soaked liquor from Omija with freeze-thawing treatment were analyzed during the extraction periods. Each of the frozen and freeze-thawed Omija samples was soaked in 35% ethanol, extracted for 15 days, and used for analysis. The frozen and freeze-thawed samples showed a tendency toward better color and higher antioxidant activity and major component levels than the controls, and freeze-thawing was the best. The results of this study showed that freeze-thawing treatment improved the color, antioxidant properties, and level of the major components of Omija soaked liquor, and freeze storage is suitable for making soaked liquor.

• Preventive Nutrition and Food Science
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• 제1권2호
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• pp.252-255
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• 1996

As an index of freeze-injury of yeast, the leakage of intracellular substances from yeast cells after freeze-thawing was investigated. It was found that much more ultraviolet-absorbing substances leaked out from non-freeze tolerant yeast (NETY) than from freeze-tolerant yeast. Furthermore, the rate of leakage of cellular substances form NFTY during incubation exceeded that of FTY, indicating that NFTY is more susceptible to freeze-injury than FTY during frozen-storage. An apparent degradation of phospholipid was observed during incubation of perfermented frozen-cells of NFTY, while little change of phospholipid occurred in FTY, These results suggested that the difference in the sensitivity of yeast might be due to the strength of cell membrane in terms of the degradation of phospholipid by enzymes, phospholipases, attached to cell membranes.

• 한국축산식품학회지
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• 제44권4호
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• pp.758-778
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• 2024

This study assessed previous research aimed at mitigating the adverse effects of freeze-thawing on meat quality. Specifically, it focuses on assessing the physicochemical alterations in meat resulting from freezing, freeze-thawing, or technologies to minimize these alterations. Recent studies have focused on conventional freeze-thaw technology applicable across various livestock species and muscle types. However, recent research has indicated the necessity for developing freeze-thaw technology considering the unique characteristics of individual muscles. In this review, we summarize previous studies that have compared alterations in the physicochemical properties of primary muscles owing to freezing or freeze-thawing. Despite the introduction of various technologies to significantly reduce the adverse effects on meat quality resulting from freeze-thawing, it is essential to consider the unique characteristics (proximate composition, pH, and muscle fiber characteristics) of individual muscles or cuts to develop enhanced the freeze-thaw processing technology.

• 한국축산식품학회지
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• 제34권4호
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• pp.482-495
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• 2014

The objectives of this study were to know the effect of repeated freeze-thaw cycles of beef on the sensory, physicochemical quality and microbiological assessment. The effects of three successive freeze-thaw cycles on beef forelimb were investigated comparing with unfrozen fresh beef for 75 d by keeping at $-20{\pm}1^{\circ}C$. The freeze-thaw cycles were subjected to three thawing methods and carried out to know the best one. As the number of freeze-thaw cycles increased color and odor declined significantly before cook within the cycles and tenderness, overall acceptability also declined among the cycles after cook by thawing methods. The thawing loss increased and dripping loss decreased significantly (p<0.05). Water holding capacity (WHC) increased (p<0.05) until two cycles and then decreased. Cooking loss increased in cycle 1 and 3, but decreased in cycle 2. pH decreased significantly (p<0.05) among the cycles. Moreover, drip loss, cooking loss and WHC were affected (p<0.05) by thawing methods within the cycles. 2-Thiobarbituric acid (TBARS) value increased (p<0.05) gradually within the cycles and among the cycles by thawing methods. Total viable bacteria, total coliform and total yeast-mould count decreased significantly (p<0.05) within and among the cycles in comparison to the initial count in repeated freeze-thaw cycles. As a result, repeated freeze-thaw cycles affected the sensory, physicochemical and microbiological quality of beef, causing the deterioration of beef quality, but improved the microbiological quality. Although repeated freeze-thaw cycles did not affect much on beef quality and safety but it may be concluded that repeated freeze and thaw should be minimized in terms of beef color for commercial value and WHC and tenderness/juiciness for eating quality.

• Animal Bioscience
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• 제34권8호
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• pp.1375-1381
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• 2021

Objective: This study was conducted to determine the effect of freeze-thawed cycles (Fresh meat, F-T 1 cycle and F-T 2 cycles) on the quality characteristics of porcine longissimus dorsi muscle. Methods: A total of 20 three-crossbred pigs (Duroc×[Large White×Landrace]) were randomly obtained from a commercial slaughterhouse in Thailand. Muscle samples were immediately taken from 10 to 11th of the longissimus dorsi for histochemical analysis. The muscles were cut into 2.54 cm-thick chops. A minimum of 20 chops were used for each treatment (fresh meat, freeze-thawed 1 and 2 cycles). Individually chops were packaged in polyethylene bags and frozen at -20℃ for 6 months followed by thawing in refrigerator at 4℃ for 24 h (the 1st freeze-thawed cycle). The freeze-thawed procedure was repeated for two cycles (the 2nd freeze-thawed cycle). Thawing loss, shear force value, citrate synthase activity and muscle fiber characteristics were determined on the muscles. Results: Results showed that increasing of freeze-thawed cycle increased the thawing loss (p<0.01) and citrate synthase activity (p<0.001). Shear force value of fresh meat was higher than freeze-thawed 1 and 2 cycles (F-T 1 cycle and F-T 2 cycles). Freeze-thawed cycles affected muscle characteristics. Muscle fiber area and muscle fiber diameter decreased with an increasing number of freeze-thawed cycles (p<0.001), while the thickness of endomysium and perimysium were increased (p<0.001). Conclusion: Repeated freeze-thawed cycles degraded muscle fiber structure and deteriorated pork quality.

• 한국구조물진단유지관리공학회 논문집
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• 제13권6호통권58호
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• pp.115-125
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• 2009

건축물의 보수 보강 시 섬유보강 폴리머를 이용한 부착공법을 이용한 보수 보강이 행해지고 있으며, 특히 CFRP(carbon fiber reinforced polymer)는 이러한 RC 구조부재의 보강재로 널리 활용되고 있다. 그러나 외부 환경적 요인에 의해 열화되는 즉, 동결융해 환경이 RC 보에서의 CFRP 보강성능에 미치는 영향에 관한 연구는 전무한 실정이다. 따라서 본 연구에서는 AE 기법을 통해 CFRP와 RC 부재 내부의 손상진전에 따라 발생하는 AE 신호를 계측함으로써 CFRP로 보강 후 동결융해에 의해 열화된 RC 구조물의 파괴기구 규명을 위한 기초자료를 마련하고자 한다.

• 한국건축시공학회지
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• 제15권2호
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• pp.201-207
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• 2015

본 연구에서는 고로슬래그 다량치환 콘크리트의 탄산화 저항성 및 내동해성 향상을 위하여 팽창성 인공 기포인 Expancel과 ERCO를 조합 사용하고 그에 따른 일련의 실험을 진행하고자 한다. 연구결과에 따르면 ERCO 치환에 따라 비누화반응에 의한 모세관공극 충전효과로 탄산화 저항성이 향상되었으며, 이 때 문제점으로 지적된 내동해성 저하현상을 개선하기 위하여 Expancel을 사용하였는데, Expancel 치환율이 증가함에 따라 내동해성이 대폭 개선되는 것으로 나타났다. 이는 Expancel이 외부압력에 의해 선택적으로 체적축소현상과 기포간격계수의 감소에 기인한 결과로 판단된다.