The conditions of blanching, freezing, and thawing for Shepherd’s purse (Capsella bursa-pastoris [L.]) were studied to improve its quality attributes during frozen storage. The washed samples were blanched with water at 100oC for 10, 20, 30, and 40 s. They were then soaked in cold water. The quality characteristics of the samples such as pH, texture, hardness, color value, and total viable cell were analyzed. The samples blanched for 30 s were frozen and thawed under several conditions and their physicochemical characteristics were analyzed. The pH value of raw samples was higher than that of the blanched sample. The values of brightness (L*), redness (a*), and yellowness (b*) decreased after blanching except the L* value of root at the condition of blanching for 40 s. Upon considering the bacterial cell counts, the proper condition was determined to be 30 s of blanching time. Blanching for 30 s was the optimal pre-treatment for minimizing the quality deterioration of the shepherd’s purse for freezing. Regarding its color change and microbial safety, faster freezing and thawing methods made less changes on the quality of frozen samples. Consequently, immersion freezing and radio-frequency thawing were the most effective in minimizing the quality change.

Food freezing preservation is an important process due to its high quality and long shelf-life. In order to improve the quality of frozen sweet potato stem, the freezing rate, thawing, and packaging method was optimized by the determination of physical properties. There was no significant difference among the treatment of freezing rate. Further, the drip loss of sweet potato stem was higher at a relatively fast freezing rate (immersion freezing) than at slow freezing rate (natural convection freezing at -20 or -40oC). For the comparison of packaging methods, the aircontaining packaged sweet potato stem had the lowest significant differences from the result of color, pH, and hardness. From the result of the drip loss, the high frequency and microwave using thawing samples were more effective than room temperature and water thawing. Therefore, fast freezing and thawing rate with air-containing package were recommended to obtain the better quality of sweet potato stem.

본 연구에서는 다양한 냉동기법인 자연냉동 및 강제송풍 식냉동, 극저온냉동과 다양한 해동방법인 자연해동, 유수해 동, 초음파해동, 전자레인지해동을 통하여 물리적 변화를 최소화 하는 냉·해동공정을 찾으려 했다. 당근의 경우 품 질을 변화 시키는 요인은 해동방법보다는 냉동방법이 더 영향력이 있다. 해동감량 및 보수력의 변화를 관찰한 결과 급속냉동(강제송풍식냉동, 극저온냉동)을 한 경우 품질유지 에 더 효과적이었다. 경도는 냉·해동공정 보다는 블랜칭 처리를 한 것이(열처리) 유의적으로 품질이 저하되는 것을 관찰하였다. 즉 열처리가 당근의 물성에 영향을 더 미치는 것으로 판단된다. 색도 및 pH 경우, 냉·해동공정에 의해 크게 영향을 받지 않는 것으로 나타났다. 당근의 전체적인 품질을 최대한 유지 하기 위해서는 냉동법의 고려가 해동 법 보다 중요하며, 다양한 냉동방법 중 급속냉동처리하는 것이 효과적인 것으로 판단되며, 유지하고자 하는 당근 품 질 특성 별로 최적의 냉·해동공정을 선정하는 것도 효과적 이라 생각한다

The pre-treatment conditions of butterbur stem such as blanching, freezing, and thawing were studied to optimize it for producing frozen butterbur stem to improve its storage ability. Butterbur stems were hot water blanched at 100oC for 3, 5, or 7 min respectively and then soaked in cold water. After peeling out and cutting into blocks (4.5×1.0×0.5 cm), butterbur stems were air-dried for 5, 10, or 15 min respectively. Dried samples were analyzed for their physicochemical properties. With blanching, the hardness value increased from 2.91 kg to 3.64 kg (p>0.05); however, adhesiveness decreased drastically after 5 min of blanching (p<0.05), which changed to a crisp texture. In addition, considering other physicochemical properties, it was assumed that 5-min blanching was optimal pre-treatment to maintain the original quality of butterbur stem for freezing. Five-minute blanched butterbur stems were airdried 5 min, frozen and thawed with several methods, and analyzed for their properties. Considering the thawing loss, hardness, and color change, the fastest freezing and thawing method had the lowest changes on the quality of frozen butterbur stem. Therefore, to produce frozen butterbur stem, it was assumed that immersion freezing and running water or room temperature thawing (25oC) were the best process.

This study was conducted to investigate performance of methods for cooking and thawing frozen cooked rice to retard retro-gradation of cooked rice. For this research, That was executed rice's physicochemical and sensory characteristics test through the way of boiling rice or thawing, and found out best way for retro-gradation and taste. This study showed the rice cooked by pressure rice pot has less dehydration during freezing and thawing, and thawed rice by micro wave has less dehydration. Repetition of freezing and thawing resulted increasing of hardness and chewiness, and decreasing of adhesiveness and cohesiveness. The rice cooked by convotherm oven or pressure rice pot has less increased hardness while freezing and thawing. Adhesiveness was superior when rice was cooked by pressure rice pot. The rice thawed by microwave had more hardness than thawed in room temperature.

Recently, the concern on the deterioration of concrete pavement due to de-icing salts and its counter measurements has been increased. Especially, a scaling phenomenon of concrete is defined as a general loss of surface mortar or mortar surrounding the coarse aggregate particles on a concrete surface. This problem is typically caused by the expansion of water due to freezing and thawing cycles and the use of de-icing chemicals. This paper discusses the testing conditions of freezing-thawing and scaling resistance.

The sensory properties of Kalopanax pictus and Cedrela sinensis shoots were analyzed according to their blanching conditions and the thawing methods used. For the Hunter colors, the K. pictus that was blanched without adding salt for 6 min had the highest L value, and the C. sinensis that was blanched with 1% salt for 6 min had the highest L value. The chlorophyll content of K. pictus was 141.1 mg% when it was blanched for 3 min with 2% salt, and the chlorophyll content of C. sinensis that was blanched without adding salt for 6 min was highest (124.8 mg%). When K. pictus and C. sinensis were blanched without salt addition for 3 min, their texture showed a higher value than that of the other samples. The sensory test result showed the highest overall preference for the sample that was blanched without adding salt for 3 min, among all the samples. The L value of the K. pictus that was thawed in a microwave oven was significantly higher than that of the other samples, but the L value of the C. sinensis that was thawed at 4℃ was higher than that of the other samples. As for the overall preference for the samples according to the thawing method used, K. pictus and C. sinensis scored highest in the case of thawing in a microwave oven.

본 연구는 오가피순과 두릅의 소비 확대와 가공품 개발의 전처리로 필수적인 blanching 조건을 설정하기 위해 blanching 온도와 식염의 농도에 따른 품질 변화와 관능적 특성을 평가하고자 하였다. 또한 해동조건에 따른 이화학적 및 관능적 특성을 평가하여 오가피순과 두릅의 품질을 향상시킬 수 해동조건을 설정하고자 하였다. Blanching은 식염 첨가량(무첨가, 1%, 2% 첨가)과 blanching 시간(4분, 7분)을 달리하였으며, 해동

홍고추를 원료형태에 따라 원형, 세절, 분쇄로 제조하여 및 저장고에 보관하였다. 고추의 표면색도는 저장온도 조건에 따라 저장일수가 증가할수록 약간 감소하는 경향을 보였으며, 비타민 C 함량은 원형 홍고추가 세절고추나 분쇄고추보다 저장기간 동안 완만하게 감소하는 경향을 보였다. 저장온도별로는 저장군에서 비타민 C 함량이 가장 높게 유지되었으며, 저장군에서 저장 2개월째 50% 이하로 급격히 감소하였다. 유리당 함량은 저장일수가 증가할수록