• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.258-258
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• 2013

최근 건조 제품의 양질화, 고급화 및 편의화가 요구되어 이를 충족시키기 위한 새로운 건조방법이 계속 개발 되어 왔다. 이러한 방법들 중에서 저온과 진공하에서 건조가 이루어지는 진공 동결 건조는 가장 완벽한 건조 방법으로 최근 실용화 되고 있다. 진공동결건조란 건조의 한 종류로 수분을 함유한 시료를 동결시킨 후 진공펌프를 이용하여 수증기압을 3중점 이하로 낮추어 얼음을 직접 증기로 만드는 승화의 원리에 의해서 얻어진다. 분무진공동결건조의 특징은 (1) 물리적구조의 보존성, (2) 화학적인 안정성, (3) 생물학적인 활동의 보존성, (4) 제품의 높은 복원성 및 재생성이다. 따라서 분무진공동결건조 기술은 크게 진공, 분무, 동결, 건조, 멸균 등과 같은 요소기술의 복합기술이라 할 수 있다. 분말을 제조하기 위해서 진공동결건조 후 분쇄하는 방법을 사용하나 본 방법에서는 정밀화학품 제조를 위해서 분무진공동결건조 방식을 사용한다. 이를 통하여 적당한 크기인 5~10 um의 입경 제조가 가능하고, 공기동력학적인 입경이 기존 방식에 비해 작아서 허파까지의 운반효율이 1.5~2배 우수하다. 화학, 의학 분야에서의 분무동결 건조는 주로 민감한 제품, 즉 생물학적 고유성의 손상 없이 물을 제거하는데 사용되어 영구적으로 저장 가능한 상태로 보관할 수 있으며 물의 첨가로 원상태로 복구할 수 있어서 매우 각광을 받고 있다. 의약용 냉동건조 제품은 항생물질, 박테리아, 혈청, 백신, 검사 약물, 단백질을 포함하는 생물공학 제품들, 세포, 섬유, 화학제품 등이 있으며 주로 vial 또는 ampule 상태로 건조가 이루어진다.본 연구에서는 원료를 $-194^{\circ}C$의 액체질소에 분무시켜 동결된 미립자를 형성한 후 진공 및 저온상태에서얼음의 승화(sublimation)에 기반한 1차 건조와 수증기 탈착(desorption)에 기초한 2차 건조 과정으로 구성된 분무진공동결건조기를 개발하였다. 분무동결 과정의 해석을 통해 2유체식 노즐을 통해 분무된 미세 입경의 액적이 액체 질소 표면까지 도달하는 회수률, 분무 노즐의 위치, 운전 조건 및 용기의 설계의 최적화를 수행하였다. 초기 액적속도, 분무노즐의 높이, 흡입구 추가에 따른 액적 유동 및 회수의 특성을 제시하였으며 이를 통한 분사시스템 고도화 가능성을 제시하였다. 구형의 미세 입자가 적층된 제품의 동결건조 공정의 해석은 흡착승화 모델(sorption sublimation model)을 기반으로 다음과 같은 열전달, 물질전달, 상변화 모델을 고려하여 유도되었다. 분무노즐 및 냉동/진공 배기계 시작품을 개발하여, 표면의 고다공도를 갖춘 입경 3~20 m 정도의 시료를 얻을 수 있으며, 동역학적 입경 5 m 충족함을 확인하였다.

• Food Science and Preservation
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• v.21 no.3
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• pp.341-349
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• 2014

The antioxidative effect and quality characteristics of different drying methods (hot air drying, far-infrared radiation drying, vacuum freeze drying) from Schizandra Chinensis Baillon were investigated. The moisture contents and water activity(Aw) contents each 4.46% and 0.38 values of the vacuum freeze drying were lower than those of other samples. A significant not difference in pH values occurred in all samples (p<0.05). The highest content $^{\circ}brix$ vacuum freeze drying was $6.60^{\circ}Brix$ respectively. The turbidity values of the samples were hot air drying 8.24 T%, far infrared radiation drying 0.32 T%, vacuum freeze drying 71.85 T%. The Hunter's L, a and b values of vacuum freeze drying were higher than those of other samples. The order of the free sugar content was glucose>fructose>sucrose, and that of the total free sugar contents were vacuum freeze drying (6.33 g/100 g) > far infrared drying (5.01 g/100 g) > hot air drying (3.73 g/100g). Antioxidant acitivy (DPPH radical scavenging, ABTS radical scavenging) and total phenol, total flavonoid, and total tannin content was highest in vaccum freeze drying than other different drying methods except nitrite scavenging ability.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.179.1-179
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• 2003

본 연구는 각종 영양성분과 기능성 물질을 함유한 식용마의 소비확대와 새로운 가공식품을 개발하고자, 당절임한 식용 마의 건조방법에 따른 물성 및 일반 성분의 변화를 조사하였다. 동결건조한 당절임 식용마의 명도는 높았고 적색도와 황색도는 열풍 및 진공 건조한 것에 비해 낮았으며, 수분함량과 재수화율은 동결건조한 것이 높게 나타났다. 수용성 단백질은 동결건조한 것이 6.43mg/100g으로 가장 낮았으며 총당과 환원당의 함량은 건조방법에 따라 뚜렷한 차이가 없었다. 주요 유기산은 malic, acetie, citric acid 이었고, acetic, citirc acid는 열풍 및 진공 건조한 것이 많았으나 malic acid는 동결 건조한 것이 월등히 높게 나타났다. 구성아미노산은 진공 건조한 것에 많았으며, 유리아미노산은 큰 차이가 없었다. 총 비타민 C함량도 별다른 차이가 없었으나 환원형 비타민 C는 동결이 산화형 비타민 C는 열풍 및 진공 건조한 것이 높게 나타났고, 무기질 함량은 K, Na, Mg의 함량이 많았다. 마 스낵의 관능검사에서는 열풍 및 진공건조에 비해 동결 건조한 것이 우수한 것으로 평가되었으며, 전자현미경적 관찰에서는 열풍 및 진공 건조한 것은 세포와 세포벽의 형태를 찾아 볼 수 없었으나 동결 건조 한것은 세포의 형태와 세포벽의 파괴가 일어나지 않았다. 본 연구는 당절임한 식용 마의 건조 방법에 따른 물성 및 성분의 변화를 조사한 결과, 동결건조한 것이 품질이 우수하였고, 영양성과 기능성을 함유한 마의 가공 식품의 개발의 가능성을 제시한다.

• Food Science and Preservation
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• v.22 no.1
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• pp.56-62
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• 2015

In this study, the quality characteristics of different drying methods of Aronia melanocarpa, which contains large amounts of bioactive substances, were investigated for the improvement of their practical use. During the drying period, the weight reduction was the highest with vacuum freeze drying (81.6%). The water content was reduced to the maximum level when vacuum freeze-drying was used. With regard to the color value measurement results, there were no significant differences in the $L^*$ value. Values of $a^*$ and $b^*$ were increased in vacuum freeze drying and cold air drying, but decreased in hot air drying. The hardness was increased dramatically after 36 hours of hot air drying, while with cold air drying, it increased slowly until 132 hr and increased rapidly after 132 hr. The dried yield was the highest with cold air drying (24.2%). As for the general component analysis results of Aronia melanocarpa, the moisture content was the lowest, and the crude protein and crude fat contents were the highest with vacuum freeze drying. No difference in pH value was shown among the dried Aronia melanocarpa obtained from the different drying methods, but the sugar content was the highest with vacuum freeze drying. The mineral content was the highest with cold air drying, and K, Ca, Mg, and Na were the major minerals. The free sugar content of dried Aronia melanocarpa was found to be 5.92~20.59 g/100 g, and the highest free sugar content was found with vaccum freeze drying.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.3
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• pp.342-347
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• 2007

Physicochemical properties of onion powder as influenced by drying methods were investigated. Moisture contents of onion powder were 13.29%, 12.99%, and 10.78% for samples dried using hot-air dryer, freeze dryer, and vacuum dryer, respectively. There were no significant differences in crude fat, crude protein, and crude ash content (p>0.05) depending on the drying methods. Samples prepared by freeze drying showed a significantly higher L-value as compared with those prepared by hot-air and vacuum drying (p<0.05). Scanning electron micrographs showed that freeze drying produced smaller particle-sized sample which in turn resulted in the higher porosity of the sample. Freeze dried samples revealed significantly lower degree of rehydration than other samples (p<0.05) probably due to small particle size of the sample. Water solubility of freeze dried sample appeared to be higher than that of other drying methods while the swelling ratio of the same sample appeared to be lower than that of the others. Browning index was significantly lower in samples prepared by freeze drying (p<0.05) but not significantly different between samples dried by hot-air and vacuum drying. Vitamin C content was higher in freeze dried onion powder due to the lower temperature applied to the sample. Freeze dried onion powder contained significantly lower amount of total polyphenol and higher amount of total sugar as compared to other samples (p<0.05).

• Food Science and Preservation
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• v.23 no.7
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• pp.1018-1025
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• 2016

To investigate biological activities in Aronia melanocarpa various drying methods were employed such as vacuum freeze drying, hot air drying and cold air drying. DPPH radical scavenging activity and ABTS radical scavenging activity of vacuum freeze dried Aronia melanocarpa was higher than hot and cold air dried Aronia melanocarpa. Vacuum freeze drying method showed the greatest contents of total phenol (15.34 g GAE/100 g), flavonoid (3.10 g GE/100 g) and tannin (2.46 g TE/100 g). Total anthocyanin content decreased to 163.52 mg C3G/100 g and 50.15 mg C3G/100 g for hot and cold air drying, respectively. Vacuum freeze-dried method increased the total anthocyanin content (743.09 mg C3G/100 g) when compared with fresh Aronia melanocarpa (163.52 mg C3G/100 g). Total proanthocyanidin content of vacuum freeze dried Aronia melanocarpa has increased to 6.21 g CE/100 g more than eight times compared with fresh Aronia melanocarpa (0.71 g CE/100 g). Chlorogenic acid and neochlorogenic acid content of vacuum freeze dried Aronia melanocarpa were higher than hot air dried and cold air dried Aronia melanocarpa, increasing about three times compared with fresh Aronia melanocarpa. These results suggested that vacuum freeze drying is optimal drying method to enhance biological activities in Aronia melanocarpa.

• Food Science and Preservation
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• v.6 no.3
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• pp.319-323
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• 1999

This study was conducted to minimize the deterioration of dried kiwifruit quality. Osmotic dehydration was carried out as pretreatment before drying. After the kiwifruits were pretreated under optimized osmotic dehydration conditions, they were dried by three drying methods(hot air drying, vacuum drying, freeze drying). Hot air drying and vacuum drying were superior to freeze drying in the drying speed. But vacuum and freeze drying preserved more vitamin C than hot air drying. Also, osmotic dehydrated kiwifruit kept better quality than nontreated kiwifruit. Diffusion coefficient which describes moisture transfer, was high in drying process pretreated with osmosis. The changes of vitamin-C followed the second-order reaction rate equation with high RE, respectively.

• Korean Journal of Food Science and Technology
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• v.20 no.3
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• pp.350-356
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• 1988

A pilot plant scale freeze dryer was designed and manufactured and its performance was tested. Freezing capacity of water vapor in the developed freeze dryer was 8㎏/batch and heating and defrosting methods were conduction and hot gas types, respectively. And exhausting time of vacuum pump was 7-8 minutes and temperature of cold trap was kept below $-50^{\circ}C$. In the freeze drying of fruits and vegetables, its optimum and maximum drying capacities were 2 and 4㎏/batch, respectively. Performance of the new freeze dryer was compared quite well with a foreign made freeze dryer.

• Journal of Life Science
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• v.10 no.3
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• pp.229-235
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• 2000

The absorption characteristics of Korean yam powder according to different drying methods were investigated. The physical properties of yam powder by different drying methods were showed the biggest porosity in freeze drying sample, while the smallest in hot air drying sample. No difference was founded in proximate compositions of yam powder by various drying methods. The amount of total phenolic compound and Vit C were showed the bigger decrement in freeze dried sample than other drying methods. The time reaching to equilibrium moisture content were determined in 12 days. Monolayer moisture contents were predicted to 0.0508∼0.0588 by BET equation and 0.0705∼0.0811 g H2O/g solid by GAB equation. BET equation for isothermal absorption curve showed over 0.95 R-square for every drying methods. GAB equation showed over 0.99 in vacuum and freeze drying but a poor R-square in hot air drying.

• Korean Journal of Food Science and Technology
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• v.33 no.2
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• pp.245-251
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• 2001

This research was conducted to study the changes in physical characteristics of mushrooms (Agaricus bisporus) as influenced by drying methods. Samples were dried using either hot air drying, vacuum drying, or freeze drying and changes in the color, browning index, hardness and rehydration rate were evaluated by response surface methodology. Hot air drying resulted in the fastest drying of sample as compared to other methods. The rate of drying was most affected by the environmental temperature rather than air velocity or vacuum pressure. The overall color difference increased as the temperature and air velocity increased. The overall color changes of the freeze dried samples were minimal as compared to those of fresh mushrooms. The hot air dried samples showed the greatest changes in the overall color, browning index as well as hardness. The freeze dried samples showed the best rehydration characteristic and maintained the best overall quality after drying.