Cold-pressed rapeseed oil (CPRO) is a rich source of bioactive components, but it is more susceptible to deterioration due to absence of chemical refining. Proper storage conditions are essential to maintain oil quality. This study evaluated the quality properties of seed-stored oil (SSO) and oil-stored oil (OSO) under various storage conditions. Both the seeds and the CPRO obtained from the ‘Jungmo7001’ and ‘Yuryeo’ varieties were stored for 24 months at 4℃, 25℃, and ambient temperature (AT). After 24 months, the acid value (AV) at 4℃ was lower than at 25℃ and AT. Additionally, the AV increased by 3.0-fold in SSO and 1.9-fold in OSO at AT compared to initial storage levels. OSO was found to be relatively more stable against oxidation than SSO. The canolol content in SSO increased with both storage temperature and period, but this was not observed in OSO. However, no changes in fatty acid composition or tocopherol content were noted based on the storage conditions, indicating that these properties remained relatively stable during storage. These results provide foundational data for the stable distribution of CPRO.

This study was conducted to examine the microbiological quality indicators (total bacterial count and coliform count) and physicochemical quality indicators (pH, redness, volatile basic nitrogen [VBN] content) of meat according to various storage temperatures (20~15oC) and packaging methods (wrap, vacuum). Based on these results, we proposed a safe consumption period. Redness, pH, and VBN content were not considered appropriate for setting the expiration date, as the redness and pH of the meat after spoilage were better than the standard values for both vacuum and wrap packaging (p<0.05). Additionally, the VBN content at 2 and 4oC increased slightly (fresh level) until the initial time of spoilage (1.0×106 colony-forming unit [CFU]/cm2) and then increased rapidly thereafter. Therefore, the results were not consistent with microbial spoilage. When the decay point was evaluated based on the presence of microorganisms, vacuum packaging extended the storage period approximately 2.5-fold when compared with wrap packaging, and the meat could be stored at 2 or 4oC for 40 or 23 days, respectively. Therefore, to evaluate meat quality, microbial indicators should be considered first. The microbiological standards proposed in this study can be used for safety management during the distribution of meat. However, to ensure meat safety, additional investigations of appropriate indicators of freshness must be conducted.

Physicochemical properties and storage stability of plant-based alternative meat prepared with low-fat soybean powder (LPAM) treated by supercritical-CO2 and those of full-fat soybean powder (FPAM) were compared. Ash and crude protein contents were higher in LPAM than in FRAM. Water absorption capacity and oil absorption capacity were significantly higher in LPAM than in FPAM. Water binding capacity was higher in LPAM than in FPAM during a 20 days storage period at 5℃ and pH was significantly lower in LPAM than in FPAM after a 5~10 days storage period. Hardness, gumminess and chewiness significantly increased with the increase in the storage period, and the three were significantly higher in LPAM than in FPAM after 10 days and 20 days of storage. The acid value showed no remarkable difference according to the storage period in LPAM; however, it was significantly higher in FPAM than in LPAM after 20 days of storage. The peroxide value and TBA value were significantly increased according to the storage period, and were significantly lower iin LPAM than in FPAM during all the storage periods. Therefore, the use of low-fat soybean powder may be effective in improving oxidative stability during storage in the production of plant-based alternative meat.

In order to respond to environmental pollution, developed countries, including Korea, have begun to conduct research to utilize hydrogen energy. For mass transfer of hydrogen energy, storage as liquid hydrogen is advantageous, and in this case, the volume can be reduced to 1/800. As such, the transportation technology of liquefied hydrogen for ships is expected to be needed in the near future, but there is no commercialized method yet. This study is a study on the technology to test the performance of the components constituting the membrane type storage container in a cryogenic environment as a preparation for the above. It is a study to find a way to respond by analyzing in advance the problems that may occur during the shear test of adhesives. Through this study, the limitations of ISO4587 were analyzed, and in order to cope with this, the specimen was supplemented so that fracture occurred in the adhesive, not the adhesive gripper, by using stainless steel, a low-temperature steel, to reinforce the thickness. Based on this, shear evaluation was performed under conditions lowered to minus 243℃, and it was confirmed that the breaking strength was higher at cryogenic temperatures.

예로부터 식품과 한약재로 널리 활용되어 온 매실은 호흡급등형 과실로 수확 후 상온에서 보관하면 며칠 내로 황변이 발생하고 물러지는 등 후숙이 빠르게 진행된다. 본 연구는 이러한 후숙이 진행될 때 수확 당시 색도가 품질과 영양적인 측면에 미치는 영향과 보관 조건에 따른 변화의 정도를 비교･분석하고자 한다. 이를 위해 같은 날에 수확한 매실을 색도에 따라 청매와 황매로 구분하고 상온, 냉장, 냉동 보관하는 동안에 발생되는 물리･화학적인 변화를 조사하였다. 수확 당일의 측정값과 비교하여 10~15% 이상 변하는데 소요되는 시간을 고려하면, 매실의 물성 변화는 저장기간 전반에 걸쳐 수확일의 색도 차이에 따라 뚜렷한 영향을 받지 않는 것으로 나타났다. 모든 저장 온도 조건에서 수확일과 비교한 실험일의 경도 감소가 가장 두드러졌고, 색도와 사과산의 변화도 빠르게 진행되었으나, 가용성 고형분과 pH의 변화는 거의 나타나지 않았다. 매실은 상온 보관의 경우 대략 4일 이내, 냉장 저장의 경우 대략 20일 이내에서 물성의 변화가 약 10% 이하로 적게 나타나며 품질을 유지하는 것으로 나타났다. 냉동 저장의 경우 색도와 경도는 저장 초기에 급격히 변하지만, 다른 물성은 대체로 장기간 유지되었다. 따라서 본 연구 결과를 토대로 저장 조건에 따른 물성 변화를 고려하여 매실의 저장 방법과 적절한 사용 시기를 결정할 것을 제안한다.

This research aims to investigate pudding with grain-added yogurt for its quality characteristics and viability during cold storage. The yogurt was fermented until its pH was 5.10±0.05 after inoculating the probiotic strain (Bifidobacterium lactis, BB-12) into the milk base containing grains. The yogurt was added to prepare probiotic puddings. During cold storage of the puddings at 4±1oC for 4 week, the quality characteristics (pH, acidity, texture) and the viability of BB-12 in pudding were determined and compared to control (only milk base). As a result, MR had a significantly lower pH and higher acidity than those of other samples. In texture properties, including hardness, gumminess, and chewiness, MSIR showed the significantly highest value, and the pudding with inulin was significantly higher than rice flour in all textures. For the viability of BB-12, pudding with milk was significantly lower than pudding containing milk and soymilk, suggesting that soymilk helps maintain viability. MR showed significantly higher viability than MI in the milk-based pudding, indicating that rice flour is more effective than inulin. Therefore, the addition of soymilk, inulin, and rice can maintain quality characteristics and viability of BB-12 in the pudding.

This study was carried out to investigate milling's effect on the pasting properties and storage stability of dry-milled rice flour. Rice flour's moisture content was increased from 9.48% to 9.80% after going through a rice polisher, and the crude fat content of rice flour was decreased from 0.91% to 0.62% after going through a rice polisher. In the color index of rice flour, the rice polisher was only affected by yellowness. The pasting properties were verified through RVA, and it was confirmed that the use of a rice polisher had no significant effect on the pasting properties. As a result of observing the changes in fatty acid value, it was ascertained that the storage period could be increased using the rice polisher. These results suggest that the rice polisher can increase the storage period without changing the pasting properties.

This study was carried out to investigate the changes of the microbiological contamination levels, pH, acidity, solid contents, total phenol contents, and color difference of cold-brew coffee products during 4 weeks at room and cold temperatures. The 17 sample coffees were purchased from regional cafes in Jeonju. Each coffee was self-blended by the cafes. Esherichia coli was not detected in all the samples, but bacteria were detected in 1 sample and yeast and molds were detected in 4 samples. Of the samples stored at room temperature (25oC) after 4 weeks, general bacteria were detected in 4 samples (3.0×101 cfu/ml-1.7×103 cfu/ml), and yeast and molds were detected in 11 samples (1.3×101 cfu/ml - 3.1×105 cfu/ml). In the case of the samples stored at cold temperature (4oC), general bacteria were detected in 3 samples, and yeast and molds were detected in 6 samples although the level of contamination was lower than that at room temperature. pH and acidity decreased during the storage period, but the total phenol content did not change. In the case of chromaticity, redness and yellowness tended to decrease.

This study examined the optimal temperature and time conditions to maintain high quality Dongchimi during the fermentation and storage period. Dongchimi was fermented at low (5oC), medium (10 and 15oC), and high (20oC) temperatures until the acidity reached 0.2, 0.3, and 0.4%. respectively. From the consumer’s preference test enrolling five consumers, Dongchimi fermented at 15oC until an acidity of 0.3% (for approximately six days) was evaluated to be the optimal status because of its high score of overall acceptance, taste, and odor of consumers. To determine the optimal storage temperature of fermentation, Dongchimi was stored at three different temperatures (−1, 2, 5oC) for four weeks after fermenting at 15oC for six days. During the storage period, most of the physicochemical properties (pH, acidity, reducing sugar content, and organic acid) and microbiological properties changed significantly in the 2 and 5oC groups, resulting in a significant change in descriptive sensory analysis of Dongchimi. These results indicate that fermentation at 15oC and storage at −1oC for Dongchimi enables it to maintain the best quality for a long time.

This study examines paraelectric Bi1.5Zn1.0Nb1.5O7 (BZN), which has no hysteresis and high dielectric strength, for energy density capacitor applications. To increase the breakdown dielectric strength of the BZN film further, poly(vinylidene fluoride) BZN-PVDF composite film is fabricated by aerosol deposition. The volume ratio of each composition is calculated using dielectric constant of each composition, and we find that it was 12:88 vol% (BZN:PVDF). To modulate the structure and dielectric properties of the ferroelectric polymer PVDF, the composite film is heat-treated at 200 oC for 5 and 30 minutes following quenching. The amount of α-phase in the PVDF increases with an increasing annealing time, which in turn decreases the dielectric constant and dielectric loss. The breakdown dielectric strength of the BZN film increases by mixing PVDF. However, the breakdown field decreases with an increasing annealing time. The BZN-PVDF composite film has the energy density of 4.9 J/cm3, which is larger than that of the pure BZN film of 3.6 J/cm3.

Quality changes in yakgwa (such as color, moisture contents, acid value, rheological properties, and viable cells) using different types of frying oils was examined for 5 weeks. During the storage period, the lightness and yellowness of all samples were increased and there was no significant difference in redness. After 5 weeks of storage, rice bran oil showed the least color difference. There was no difference in the moisture contents of all samples except for grape seed oil, while the moisture contents of yakgwa fried with grape seed oil was decreased. The acid value increased as the storage period increased regardless of the type of frying oil, and yakgwa fried with rice bran oil and grape seed oil showed a low acid value. The hardness was increased as the storage period increased, but there was no difference in the hardness between the samples. The adhesiveness and resilience were decreased and the chewiness was increased. The total cell count did not increase significantly as the storage period, and there was also no difference in the total cell count between the samples. There was a high level of yeast and mold in comparison to total cell count, and the colony of bacteria was not detected.

Liquid storage tank is one of the major infrastructures and generally used to store gases, drinking and utilizing water, dangerous fluids, fire water and so on. According to the recent reports and experiences, the tank structures are damaged in many earthquakes due to their low energy dissipating capacity. Therefore, many researchers have been tried to know the dynamic properties of the tanks including liquids. However, vary limited experimental studies are carried out using relatively small tank models. In this study, a series of shaking table tests are performed with maximum 2 m cubic rectangular liquid storage tanks made of steel to measure the natural frequency and estimate damping coefficient of impulsive and convective mode of the tanks. Especially, the damping values under different shapes and excitation methods are estimated by logarithmic decrement method and half power band-pass method and compared with current design code and standards such as ASCE 7, Eurocode 8 and NZS. Test results show that the impulsive mode damping is around 2% which is proposed by general standards and codes but the impulsive mode damping is 0.13% average that is slightly lower than the code recommendation.

The effects of high hydrostatic pressure (HHP) or concentration treatment or sodium hydrogen carbonate addition on microbial and quality properties of cold drip liquid coffee were investigated during storage at room temperature. Cold drip liquid coffee was determined to pH, acidity, general bacteria, and Y&M (Yeast and Molds) according to HHP treatment or adding 0.2% sodium hydrogen carbonate for 40 days storage at 20°C. Also, an equivalent mixture of concentrated coffee and cold drip liquid coffee or liquid coffee with 0.2% sodium hydrogen carbonate was used for determining the sensory evaluation, due-trio and preference test. The cold drip liquid coffee with 0.2% sodium hydrogen carbonate had higher pH and lower titratable acidity than the control during 40 days storage at 20°C. Total viable cell and Y&M counts of cold drip liquid coffee added with 0.2% sodium hydrogen carbonate or treated by HHP at 300 MPa for 25 min were lower than the control during storage at 20°C. The result of the due-trio and preference tests shows that there was no significant difference between cold drip liquid coffee added to 0.2% sodium hydrogen carbonate and the control or between the equivalent mixture of concentrated coffee with cold drip liquid coffee and the control. As a results, Cold drip liquid coffee treated by HHP, concentrated by evaporation, and added to sodium hydrogen carbonate has a potential to extend a shelf life at ambient temperature storage.

본 연구는 열수침지 및 과열증기 처리한 당근을 IQF 방 법으로 급속 냉동 한 다음 -12, -18, -24 o C에서 24주 동안 저장한 후 해동하여 이화학적 및 영양학적 특성과 미생물 학적 변화를 분석하여 열처리 및 냉동 저장의 최적 공정 과정을 확립하고자 하였다. 대체적으로 과열증기 처리한 당근보다 열수침지 처리한 당근의 ΔE이 큰 값을 나타내었 고, 열처리 후 생당근에 비해 전단력이 감소하였으나 급속 냉동 후 저장 기간에 따른 유의적인 차이를 나타내지 않았 다(p>0.05). 열처리 후 생당근에 비해 총균수가 감소되었지 만 냉동 저장시 일정한 경향을 보였고, 열수침지 처리한 당근의 비타민 C 손실양이 과열증기 처리한 당근보다 더 많았다. 열수침지 처리 후 감소한 유리당의 함량은 저장 기간에 따른 변화는 없던 반면, 과열증기 처리 후 급속 냉 동 한 당근의 유리당 함량은 증가하였다. 당근의 유기산의 함량은 열수침지 처리 후 감소하였으나 과열 침지 처리 후 oxalic acid와 malic acid 함량은 증가하는 경향을 보였다. 이를 통해 열처리 후 영양 성분의 손실이 더 적은 과열증 기법의 공정 과정이 열수침지법보다 더 적절한 것으로 보 인다. 또한 -12 o C에서 저장한 당근의 비타민 C가 6개월 후 모두 파괴되었던 것을 통해 비타민 C의 파괴를 최소화하 기 위해서는 이보다 더 낮은 온도에서 냉동 저장해야 할 것이라 사료된다.