• 한국식품영양과학회지
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• 제19권6호
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• pp.555-564
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• 1990

과실쥬스와 같은 자연 생산물의 동결건조에 있어서 가공처리중 휘발성분의 보유력 변화를 알아보기 위하여 headspace gas chromatography 기술의 특징을 이용하여 동결건조 속도, 초기 고형물의 함량 및 압력 등이 어떠한 영향을 미치는가에 대한 실험결과는 다음과 같다. 동결건조 속도가 휘발성분의 보유력에 대한 영향은 현저하였으며, 동결시간이 길수록 뚜렷하였다. 동결 건조 제품에서 휘발성분의 보유력은 동결에 의해 영향을 받았다. 동결건조 조건하에서 가장 많은 휘발성분의 손실은 동결건조 초기단계, 즉 1~2 시간 사이에서 일어났다. 휘발성분의 보유력은 초기 고형물의 함량이 많을수록 높았다. 동결속도가 빠를 때보다는 늦을 때가 휘발성분의 보유력이 높았으며 높은 압력에서보다 낮은 압력에서 높았다.

• 분석과학
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• 제33권4호
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• pp.177-185
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• 2020

Human milk (HM) glycoproteins play important roles protecting infants against various pathogens. Recently, freezing HM is reported to affect some glycoproteins and freeze-drying is suggested as an alternative method. However, the effects of freeze-drying on HM glycoproteins were not evaluated yet. Six fresh HM samples were collected from three healthy mothers at 15 and 60th days of lactation from each mother. Each sample was divided into frozen and freeze-dried subgroups yielding totally 12 samples, and the glycoproteomic analysis was performed by liquid chromatography mass spectrometry. The results were compared between samples of 15 and 60th days of lactation, and before and after the freeze-drying. Totally, 203 glycoproteins were detected. The glycoprotein levels were not different between two groups of 15/60th day of lactation and before/after freeze-drying groups (P > 0.050). In addition, significant correlation of glycoprotein levels was found between the different lactation stages (r = 0.897, P < 0.001) and the status of freeze-drying (r = 0.887, P < 0.001) in a partial correlation analysis. As no significant change of HM glycoproteins was not found after the freeze-drying, we hope that introducing freeze-drying to HM banks is supported by the present study. This work was supported by the National Research Foundation (NRF) of Korea grant funded by the Korea government (MSIP) (No.2017R1D1A1B03034270; No.2020R1A2C1005082).

• 한국약용작물학회지
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• 제14권1호
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• pp.8-13
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• 2006

삼백초의 유효성분과 선도유지에 적합한 건조방법을 구명하고자 건조방법을 달리하여 건조시킨 후 건조방법별 유효성분 함량과 선도를 조사한 결과를 요약하면 다음과 같다. 1. 건조방법별 건조시간은 양건에 비해 열풍건조와 동결건조시 $88{\sim}93%$ 단축되었다. 건물수율은 동결건조 > 양건 > 열풍건조 순으로 높았고, 건조후 수분 함량은 양건 > 열풍건조 > 동결건조 순으로 높았다. 2. 총페놀성 화합물과 quercetin 관련물질 함량은 동결건조 > 열풍건조 > 양건 순으로 높았으며, 열풍건조후 볶음 또는 건조전 증자 처리를 함으로써 감소되었다. 항산화 활성은 동결건조에서 가장 높았고, 열풍건조와 양건 간에는 차이가 없었으며, 열풍건조후 볶음 또는 건조전 증자 처리를 함으로써 증가하여 총페놀성 화합물과 quercetin 관련물질 함량과는 다른 경향을 보였다. 3. 적색도 (a)는 동결건조 < 열풍건조 < 양건 순으로 낮았다. 4. 열풍건조시 부위별 총페놀성화합물과 quercetin 관련물질 함량은 꽃 > 잎 > 세절 > 줄기 순으로 높았으며, 항산화 활성도 유사한 결과를 나타내었다. 부위별 적색도는 잎 < 세절 < 꽃 < 줄기 순으로 낮았다. 5. 삼백초의 유효성분과 선도유지에 적합한 건조방법은 세절하여 동결건조하거나 잎과 꽃만을 열풍건조하는 것이 효과적이었다.

• 대한영양사협회학술지
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• 제19권4호
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• pp.389-399
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• 2013

This study compared the nutritional composition and antioxidative activity of different parts of Taraxacum coreanum (aerial parts and roots) according to different drying methods (natural drying and freeze-drying). There were no significant differences in vitamin C content in roots depending on the drying methods. However, vitamin A (P<0.01), E (P<0.001) and C (P<0.001) content of aerial parts, and vitamin A (P<0.001) and E (P<0.05) content of roots were significantly higher after freeze-drying compared to natural drying. For organic acids, the oxalic acid content of the aerial parts and roots were the highest. The total polyphenol and total flavonoid content in extracts from the aerial parts (P<0.01) and roots (P<0.05) were significantly higher after freeze-drying compared to natural drying. In addition, the total polyphenol and flavonoid content, DPPH radical scavenging activity, and antioxidative index from the natural drying and freeze-drying of Taraxacum coreanum extracts were significantly higher in the aerial parts compared to the roots (P<0.05). These results suggest that the nutritional composition and antioxidative activity of Taraxacum coreanum are higher in the aerial parts compared to the roots, and higher after freeze-drying compared to natural drying. Therefore, the aerial parts of Taraxacum coreanum could be suggested as an antioxidative functional food source.

• Journal of Biosystems Engineering
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• 제34권3호
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• pp.155-160
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• 2009

This study was attempted to quality characteristics of ginseng powder using molecular press dehydration(MD) method. Ginseng powder was dried using maltodextrin as dehydrating agents, and the quality of the ginseng powder was compared with that of freeze-drying and hot air-drying samples in terms of colors, moisture contents and grain size. The colors of ginseng powder using MD-drying and freeze-drying was better than hot air-dried ginseng powder. The moisture contents of ginseng powder using MD-drying was 9.49%, while freeze-drying was 4.14% and hot air-drying 11.71% after 72ball mill times. The grain size of ginseng powder using MD-drying and freeze-drying was better than hot air-drying ginseng powder. These results suggest that drying of ginseng powder using molecular press dehydration method is very efficient, because minimal cell destruction may be achieved.

• 한국식품과학회지
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• 제34권1호
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• pp.91-95
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• 2002

본 연구의 목적은 동결건조된 김치를 시료로 선정하여 동결건조 시간이 건조된 김치제품의 미생물학적인 특성, 관능적 특성 및 다른 품질에 미치는 영향을 조사하여 "건조김치"의 제조에 적합한 동결건조 시간을 알아내는 것이다. 김치를 24, 48, 72시간 동결건조한 후, 건조제품의 젖산균수, pH, 관능적 특성, 파쇄도, 복원성 및 수분함량, 배추조직의 미세구조를 관찰하여 동결건조 시간이 건조김치의 품질에 미치는 영향을 조사하였다. 원시료에 비하여 24시간 건조시킨 제품의 생균수 및 pH가 현저하게 변화하였으나, 그 후에는 72시간까지 거의 변화가 없었다. 24시간 건조김치보다 48시간 또는 72시간 건조김치의 전반적인 기호성이 우수하였다. 동결 건조 시간이 24시간에서 48시간, 72시간으로 증가할수록 건조김치의 파쇄성은 증가하였다. 동결건조 시간이 경과할수록 건조김치의 복원성이 개선되고, 건조김치의 중량과 함유된 수분함량은 감소하였다. 본 실험의 조건하에서는 건조김치의 제조에 적합한 동결건조 시간은 미생물학적인 측면에서 보면 24시간도 큰 문제는 없으나, 관능적 특성과 건조제품의 품질특성의 측면에서 판단하면 48시간이 보다 바람직하였다.

• Applied Microscopy
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• 제28권3호
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• pp.299-306
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• 1998

T-butyl alcohol (TBA) freeze-drying method originally designed by Inoue and Osadake (1989) was adopted to dry specimens for scanning electron microscopy and the results were compared with those dried using critical point dryer (CPD). Small pieces $(1\times1\times3mm)$ of liver of Sprague-Dawley rats were cut and fixed in 2% glutaraldehyde in 0.1 M sodium cacodylate buffer after anesthesia, and processed for scanning electron microscopy by several modifications of TBA freeze-drying methods and by the standard preparation method using CPD. The bile canaliculi and sinusoidal endothelial surface were observed. Tissue dehydrated with TBA before TBA freeze-drying preserved the structures best comparable to those prepared with CPD. This result suggests that combination of dehydration with TBA and TBA freeze-drying is a superior method to the original TBA freeze-drying method dehydrated with ethanol.

• 동력기계공학회지
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• 제15권4호
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• pp.5-10
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• 2011

In case of using rapid vacuum-freeze drying for high quality dry flower of flowering plant, the morphological and physiological characteristics of dry rose showed as the following. The dry ratio of about 82% presented after 1 day in case of using rapid vacuum-freeze drying and it was reached that the optimum storage water content of general dry products was 18%. The dry ratio of about 89% presented after 4 days. This result indicates very short dry time comparing with natural dry time of 12 days. Also, the morphological characteristics of flowering plant in case of vacuum-freeze drying showed similar shape with real flower. The contraction decreased about 9% comparing with real flower under dry time of 72 hours. But the contraction in case of natural dry decreased 36% and showed noticeable difference. The brightness which affects physiological characteristics of dry flowering plant showed lower values according to the dry process and chromaticity was thick. After 4 days, natural dry was thick with about 2 times comparing with vacuum-freeze drying. In case of vacuum-freeze drying, the quantity of anthocyanin and chlorophyl which affect discoloration and bleaching of dry flowering plant showed the clear difference comparing with natural dry method due to the sublimation by vacuum after rapid freeze with short initial time.

• Food Science and Biotechnology
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• 제16권4호
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• pp.520-525
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• 2007

The physicochemical properties of sun-dried and cyclic freeze-thaw dried Alaska pollack were analyzed to compare the 2 drying processes. The moisture content and water activity of sun-dried Alaska pollack were higher than cyclic freeze-thaw dried and 1 year-aged cyclic freeze-thaw dried Alaska pollack (hwangtae). The relatively low temperatures used in cyclic freeze-thaw drying retards lipid oxidation compared to sun drying based on the acid and peroxide values, and the levels of thiobarbituric acid-reactive substances (TBARS) in the dried fish. The water holding capacity of cyclic freeze-thaw dried Alaska pollack aged for 1 year (hwangtae) under ambient conditions at the drying location was higher than that of sun-dried Alaska pollack. The swelling of myofibrilar filaments during cyclic freeze-thaw drying may be responsible for the softening of the dried muscle protein. Aging the cyclic freeze-thaw dried Alaska pollack for 1 year contributed to an increased yellowish color of the hwangtae.

• 동아시아식생활학회지
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• 제16권2호
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• pp.180-185
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• 2006

To develop a new instant pumpkin gruel food, this study investigated the dried powder and gruel quality characteristics depend on drying method. The pumpkin powder was dried by infrared and freeze drying, and then milled to 80 mesh, after which the manufactured gruel was mixed with glutinous rice by heating. The gruels prepared by dried pumpkin powder were compared with steamed and freeze dried powder as a control, the crude protein and total sugar contents were high in the infrared drying powder, but freeze drying kept more carotenoid content. Soluble solid of gruel was higher in the freeze dried powder, and steam treated powder showed increased L and b values. Sensory test was carried out to select proper drying methods with 5-point scale. The gruel with freeze dried powder gained the highest score in overall quality. These results suggest that freeze drying could be used for manufacturing high quality instant pumpkin gruel.