• 한국축산식품학회지
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• 제28권3호
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• pp.312-318
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• 2008

The objective of this study was to investigate the changes in ice dendrite size during freezing process in gelatin matrix as a model food system in order to provide mathematical relation between freezing condition and ice dendrite size. Gelatin gel as a model matrix was frozen in unidirectional Neumann's type of heat transfer. The thermograms' analysis allowed to determine the freezing temperature of the sample, the position of the freezing front versus time, and thus, freezing front rate. The morphology of ice dendrites was observed by scanning electron microscopy after freeze-drying. We observed that the means size of ice dendrite increased with the distance to the cooling plate; however, it decreased with the cooling rate and the cooling temperature. In addition, the shorter durations of the freeze-drying process was shorter decreeing the decreased the freezing front rate, resulted in their resulting in a larger pore size of the ice dendrite pores for the sublimation channel of that operate as water vapor sublimation channels. From these results, we could derive a linear regression as an empirical mathematical model equation between the ice dendrite size and the inverse of freezing front rate.

• 한국연초학회지
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• 제18권1호
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• pp.76-84
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• 1996

Flue-cured tobaccos(cv. NC82, grade AB3O-1) expanded by super steam, volatile organic solvents(tricuorofluoromethane, propane), carbon dioxide, nitrogen, and by freeze-drying were examined for their physico-chemical properties. The expanding rate by using the organic solvents or carbon dioxide at the impregnated pressure was 70% or more, whereas the rate by super steam and freeze-drying was 49.4 and 42.9%, respectively. The contents of total sugar, alkaloid and ether extracts of the expanded tobacco by organic solvents or carbondioxide were decreased to 27.6, 20% or more, and 13%, respectively, when compared to non-expanded one. The contents of citric acid of the tobacco expanded by using trichlorofluoromethane and carbon dioxide were increased to 19.1, 14.0%, respectively. Linoleic acid in the tobacco expanded by super steam or trichlorofluoromethane was also increased to 17.3%, but malonic acid in the tobacco expanded by super steam was 18.5% less than that in the non-expanded one. Nineteen essential oil among 22 assayed in this experiment were decreased in the expanded tobaccos. Key words : expanding method, tobacco, physico-chemical properties.

• 한국식품과학회지
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• 제30권5호
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• pp.1107-1113
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• 1998

품질이 우수한 효소식품으로의 활용가능성 검토를 위해 현미를 발아시킨 후 마이크로파 진공건조로 건조하고 그 건조특성과 품질특성을 열풍건조, 진공건조, 그리고 동결건조의 경우와 비교해 보았다. 마이크로파 진공건조 1 및 2의 경우 열전달속도가 빨라 건조 개시후 5분 경과후 $60^{\circ}C$에 도달하였고 건조시간 내내 $60{\pm}2^{\circ}C$를 유지하였으나 열풍건조의 경우는 건조개시 60분 경과 후, 진공건조의 경우는 2시간 경과 후에야 $60^{\circ}C$에 도달하였다. 마이크로파 진공건조 1의 경우 건조 3시간 후 수분함량 0.08 kg water/kg solid까지 감소하였으나, 마이크로파 진공건조 2의 경우 총건조시간 2시간만에 수분함량 0.O6 kg water/kg solid까지 감소하였다. 열풍건조의 경우 건조시간 4시간만에 수분함량 0.14 kg water/kg solid까지 감소하였으나 최소한 2시간은 더 건조시켜야 할 것으로 예상되었다. 마이크로파 진공건조 1 및 2의 초기 건조속도는 0.05 kg water/kg solid/min이었으며 처음부터 건조속도가 계속 감소하는 감률건조를 보였다. 열풍건조의 경우는 초기 건조속도가 0.0057 kg water/kg solid/min으로서 마이크로파 진공건조 1 및 2의 1/10 수준이었으며 건조개시 30분까지 항률건조를 보이다가 임계수분함량 0.81 kg water/kg solid 부근부터 감률건조가 시작되었다. 건조시료의 ${\alpha}-amylase$ 활성 및 protease 활성은 마이크로파 진공건조, 동결건조, 진공건조 및 열풍건조의 순서를 보였고, diastatic activity의 경우 동결건조와 마이크로파 진공전조가 거의 대등한 품질보존효과를 보여 주었다. 이로부터 마이크로파 진공건조를 이용하여 건조할 경우 최소한 동결건조와 대등한 품질의 건조제품을 제조할 수 있으리라 예상되었다.

• E2M - 전기 전자와 첨단 소재
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• 제1권1호
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• pp.35-43
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• 1988

In this study, PLZT ceramics were fabricated by the freeze-drying and normal sintering method. The composition rate of the specimen was selected 9/65/35(La/Zr/Ti) which had good optical and dielectric properties, sintering time was varied 1, 10, 30, 50, 55, 60 and 65(hr) at 1250(.deg.C). After sintering, the optical and dielectric properties were investigated with the grain size. As the result of the experiment, the particle size of the powder prepared by freeze-drying method was less than 1(um). The relative dielectric constant was increased linearly with the sintering time and specimen sintered for 65(hr) had the highest value, 5780. Grain was grown with increasing time, in the case of specimen sintered for 60(hr), the grain size was 8.4(um). Transmittance was increased with the grain size. In the case of 8.4(um) grain size, the transmittance was 56(%). Curie temperature was decreased linearly by the surface-layer effect of space-charge. In the case of grain size, 1.8(um), 8.4(um), curie temperatures were appeared at 100(.deg.C) and 80(.deg.C), respectively.

• 한국식품과학회지
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• 제31권3호
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• pp.625-630
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• 1999

효소식품인 현미코오지를 제조한 후 마이크로파 진공건조를 적용하여 건조하고 그 건조특성과 효소활성을 열풍건조, 진공건조, 또는 동결건조의 경우와 비교해 보았다. 마이크로파 진공건조의 경우 열전달속도가 빨라 건조 시작후 $5{\sim}10$분만에 $40^{\circ}C$에 도달한 후 건조시간 내내 $40{\pm}2^{\circ}C$를 유지하였다. 열풍건조의 경우는 건조시작 10분 경과 후, 진공건조의 경우는 40분 경과 후 $40^{\circ}C$에 도달하였다. 마이크로파 진공건조의 경우 건조 2시간 후 수분함량 0.08 kg water/kg solid까지 감소하였으나, 열풍건조의 경우 건조 시작후 2시간이 경과했는데도 겨우 수분함량 0.70 kg water/kg solid까지만 감소하였다. 마이크로파 진공건조의 경우는 초기 건조속도는 0.06 kg water/kg solid/min이었으며 처음부터 건조속도가 계속 감소하는 감률건조를 보였다. 열풍건조의 경우는 건조 초기 건조속도가 0.0045kg water/kg solid/min으로서 마이크로파 진공건조의 1/10 이하였으며 건조개시 40분까지 항률건조를 보이다가 임계수분함량 0.89 kg water/kg solid 부근부터 감률건조가 시작되었다. 건조시료의 ${\alpha}-amylase$ 활력, diastatic activity 및 protease 활력은 마이크로파 진공건조, 동결건조, 진공건조 및 열풍건조의 순서를 보여 마이크로파 진공건조의 품질보존효과를 알 수 있었다.

• 한국식품저장유통학회지
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• 제24권7호
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• pp.1034-1042
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• 2017

저온 적응성 효모 SCY297의 종균 방법에 따른 생존율과 약주 제조시 양조 특성을 조사하였다. 동결건조, 송풍건조 및 액체 제형 방법으로 제조한 다음, 실온에서 장기 저장에 따른 효모의 생존율과 양조 특성을 비교하였다. 또한, 부형제로 skim milk, ${\alpha}$-lactose, trehalose를 5%씩 첨가하여 생존율과 양조특성에 미치는 영향을 조사하였다. 부형제가 첨가된 동결건조 및 액체 제형 SCY297 효모는 실온에서 15주까지 약 80% 이상의 생존율을 나타내었고, 송풍건조는 skim milk 첨가한 경우만 약 80% 이상 생존율을 나타내었다. 저장기간 및 제형화된 효모 SCY297로 약주를 발효하여 그 술덧을 분석한 결과, 동결건조 및 송풍건조된 SCY297는 무처리 SCY297보다 적정산도는 0.61, 아미노산도는 14.23 증가하였고, 알코올 함량은 5.07% 감소하였다. 액체 SCY297는 무처리 SCY297보다 pH 1.86, 아미노산도는 5.1 증가하였고, 알코올 함량은 2.9%로 감소량이 낮았다. 따라서 본 연구 결과, 종래의 고상형 방법보다 액상형 방법을 통한 종균화 가능성을 제시하였다.

• 산업식품공학
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• 제13권3호
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• pp.216-220
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• 2009

Aloe gel의 동결건조에 농축도가 서로 다른 액상 시료를 사용하였을 때 건조분말의 기능성 변화를 비교분석하였다. Aloe의 많은 기능성 중에서 유효 다당류의 농도, 기능성 작용기에 대한 FT-IR 특성, Jack bean urease 저해 효과, FAC(fat adsorption capacity)를 대상으로 하였다. 농축도가 높은 경우에 유효 다당류의 농도, urease 저해 효과, FAC 모두 상대적으로 크게 나타났다. FT-IR의 분석에서는 농축도가 높은 경우에 glucomannan의 acetyl 기에 대한 spectrum 영역인 1600-1550 $cm^{-1}$와 1450-1400 $cm^{-1}$에서 흡광도가 크게 관찰되었다. 결과적으로 Aloe gel의 동결건조시 전처리과정인 농축 공정에서는 농축도가 높을수록 유효다당류의 양과 acetyl기 함량의 수준이 크며, 간접적으로 urease 저해 효과에 따른 Helicobacter pylori의 억제 및 FAC의 증가 효과를 보였다.

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.153-154
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• 2002

Salmonella typhi Ty21a is an attenuated strain of S. typhimurium and used for oral typhoid vaccine. In an attempt to increase the stability of Ty21a manufacturing typhoid vaccine, the stability of freeze-dried Ty21a including additives at various temperature conditions was studied. In order to investigate the freeze-drying rate of Ty21a according to various absorbance, Ty21a was lyophilized by using 8% sucrose as a stabilizer. (omitted)

• Journal of Pharmaceutical Investigation
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• 제24권2호
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• pp.85-94
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• 1994

Inclusion complexes of ketoconazole (KT) with ${\alpha}-$, ${\beta}-cyclodextrin$ (CD) and dimethyl-${\beta}-cyclodextrin$ $(DM{\beta}CD)$ in a molar ratio of 1:2 were prepared by freeze-drying and solvent evaporation methods. The interactions of KT with ${\alpha}-CD$, ${\beta}-CD$ and $DM{\beta}CD$ in aqueous solution and in solid state were investigated by solubility study, infrared (lR) spectroscopy and differential scanning calorimetry (DSC). The stability constant of $KT-DM{\beta}CD$ inclusion complex (lC) was found to be the largest among three inclusion complexes. Clear differences in IR spectra and DSC curves were observed between inclusion complexes and physical mixtures (PM) of KT-CDs. It was also shown by IR spectra and DSC curves that solvent evaporation method might be. superior to the freeze-drying method in preparing the inclusion complexes of KT-CDs. The dissolution rate of KT was markedly increased by inclusion complex formation with CDs in the buffer solution at pH 4.0 and pH 6.8. The mean dissolution time (MDT,min), which represents the rapidity of dissolution, was in the order of $KT-DM{\beta}CD$ IC (3.20) < $KT-{\beta}-CD$ IC (4.36) < $KT-{\alpha}-CD$ IC (6.99) < $KT-{\alpha}-CD$ PM (17.46)< $KT-{\beta}-CD$ PM (19.36) < $KT-{\beta}-CD$ PM (28.53). The dissolution rates of KT-CD ICsprepared by solvent evaporation method were faster than those of KT-CD ICs prepared by freeze-drying method.

• Journal of Microbiology and Biotechnology
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• 제29권5호
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• pp.721-730
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• 2019

The probiotic Lactobacillus acidophilus KBL409 was encapsulated with alginate (Al) and alginate-chitosan (Al/Chi) through extrusion method. The sizes and zeta potentials of microspheres were measured to confirm encapsulation. To evaluate the protective effect of microspheres against gastrointestinal fluids, all the samples were exposed to simulated gastric fluids (SGFs, pH 1.5) at $37^{\circ}C$ for 1 or 2 h, followed by incubation with simulated intestinal fluids (SIFs, pH 6.5) for 2 h. The mucoadhesive ability of microspheres was evaluated using the intestinal epithelial cell line HT29-MTX. To extend the shelf-life of probiotics, lyoprotectants such as disaccharide and polysaccharide were mixed with free or encapsulated cells during the freeze-drying process. The size of the microspheres demonstrated a narrow distribution, while the zeta potentials of Al and Al/Chi-microspheres were $-17.9{\pm}2.3$ and $20.4{\pm}2.6mV$, respectively. Among all the samples, Al/Chi-encapsulated cells showed the highest survival rate even after exposure to SGF and SIF. The mucoadhesive abilities of Al and Al/Chi-microspheres were higher than 94%, whereas the free L. acidophilus showed 88.1% mucoadhesion. Ten percent of sucrose showed over 80% survival rate in free or encapsulated cells. Therefore, L. acidophilus encapsulated with Al and Al/Chi-microspheres showed higher survival rates after exposure to the gastrointestinal tract and better mucoadhesive abilities than the free cells. Also, sucrose showed the highest protective effect of L. acidophilus during the freeze-drying process.