• 한국식품영양학회지
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• 제31권6호
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• pp.933-939
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• 2018

The objective of this study was to determine the effects of drying methods on the quality characteristics and antioxidant activities of pumpkin (Cucurbita moschata Duch.). Pumpkins were dried naturally ($25^{\circ}C$), hot-air drying ($60^{\circ}C$), and throgh freeze drying ($-40^{\circ}C$) methods. The moisture activities were highest in the freeze dried group. The soluble solid showed no significant differences among all groups. The pH was highest in the freeze dried group. The L values were increasing in freeze dried group, whereas the b values were increased in hot-air dried group. The free sugar was highest in freeze dried group. The DPPH radical scavenging activity of hot-air dried group was higher than those of the other groups. The ABTS radical scavenging activities were highest with hot-air dried group and freeze dried group. It was established that hot-air dried group is the most effective drying method for the production of high quality dried pumpkin.

• 한국세라믹학회지
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• 제33권9호
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• pp.1057-1063
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• 1996

Y2O3-CeO2-ZrO2 powders were prepared from water-soluble salts using a coprecipitation method. The forming process of oxide and the characteristics of the calcined powders treated in different drying conditions were investigated. The oxidation was occurred at the temperature of around 40$0^{\circ}C$ and the main crystallization of ZrO2 around $600^{\circ}C$. On calcination at $600^{\circ}C$ heating lamp-dried powders consisted of agglomerates of globular morphology with average agglomerate size of 2.27${\mu}{\textrm}{m}$ and specific surface area of 68.3m2/g and spray dried powders contained dense spheric particles with average agglomerate size of 1.35${\mu}{\textrm}{m}$ and specific surface area of 11.0m2/g which exhibited low agglomeration tendency. Removal of the water by a freeze-drying technique produced calcined powders containing flake-like secondary particle structures with wide agglomerate size distri-bution of 0.1-60${\mu}{\textrm}{m}$ and specific surface area of 24.5${\mu}{\textrm}{m}$. The 20 MPa-pressed density (36.8-41.4% T,D) of calcined powders did not nealy depend on drying methods whilst compaction ratio of calcined powders derived from freeze-drying was the highest ( 6.24) among three drying methods. On continuous heating up to 150$0^{\circ}C$ the sinterability of calcined powders derived from heating lamp-drying was superior to those derived from spray-and freeze-drying. The final sintered density of calcined powders was the highest (96% T,D at 150$0^{\circ}C$) in case of heating lamp-drying.

• 한국식품과학회지
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• 제30권4호
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• pp.877-882
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• 1998

본 연구에서는 생마의 적정 건조방법을 알아 보고자 동결건조, 냉풍건조 및 열풍건조 방법으로 마를 건조시 각 건조 방법의 최적 조건을 조사하고, 3가지 건조 방법에 따른 마의 식품학적 품질 특성을 비교 평가하여 최적 건조방법을 고찰해 보고자 하였다. 동결건조시 $40^{\circ}C$ 이하로 가열하면서 건조 시키면 건조후 마고유의 색, 향, 맛과 점질성이 생마와 거의 같은 수준으로 유지되었다. 열풍건조나 냉풍건조의 경우 건조후 마의 색이 연한 백색이나 미색을 나타내지 않고 갈변되었다. 향이나 맛의 경우 냉풍건조시는 마 고유의 향이나 맛이 감소되었으며 열풍건조에서는 마 고유의 향이나 맛이 감소되었을 뿐 만 아니라 가열취나 구수한 맛도 나타났다. $40^{\circ}C$ 동결건조 마는 생마와 유사한 0.0160 Pa.s의 겉보기 점도를 나타내었으나 열풍건조와 냉풍건조는 생마의 반 이하 수준으로 점도가 감소하여 점질성을 거의 나타내지 않았다. 결론적으로 생마의 식품학적 주요 특성인 점질성, 색, 마 고유의 향과 맛을 유지하며 분산성과 용해성을 높이는 건조 방법으로는 동결건조가 가장 좋은 것으로 평가되었으며, 분말화시 분말의 용도에 적합한 용해성 및 분산성 같은 물성이 높게 나타나는 적정 입자 크기는 $40{\sim}60{\;}mesh$ 사이인 것으로 나타났다.

• 한국식품영양학회지
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• 제37권3호
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• pp.129-138
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• 2024

In this study, in order to develop an foaming tablet product using yuzu powder, yuzu powder was manufactured using different drying methods such as freeze-drying, 60℃ drying, and 40℃ drying, and then quality characteristics and functionality were analyzed. The naringin content per g of yuzu powder was 8.9 mg for freeze-drying and 8.8 mg for 60℃ drying, and the hesperidin content per g of yuzu powder was highest at 53.6 mg for freeze-drying and 46.2 mg for 60℃ drying. followed by 40℃drying (41.7 mg). The tyrosinase inhibitory activity of 60℃ dried powder was found to be twice as high as that of freeze dried powder. Accordingly, in order to develop an inner beauty product, foaming tablets were manufactured using hot air dried powder, and the quality characteristics and functional ingredients of the final foaming tablets were investigated. The foaming tablet prepared with yuzu powder content of 10 and 15% showed an inhibitory activity of tyrosinase of 73.7 %, which was 1.6 times higher than that of ascorbic acid (1 mM), which was a positive control, confirming its melanin production inhibition effect.

• Journal of Ginseng Research
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• 제14권3호
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• pp.353-356
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• 1990

The isolation of volatile compounds by vacuum-distillation with freeze-drying was tested 1 with fresh ginseng roots. The roots were frozen at-8$0^{\circ}C$; they were dried at-4$0^{\circ}C$ tinder vacuum(40 tory), for 24 hours; and the ice condensed at the silrface of condenser in the freeze-dryer was thauved at room temperature. The ether extract of the resulting aqueous solution was analyzed by gas chromatography (GC) equipped with a flame ionization detector (FID) or a nitrogen-phosphorils detecto(NPD) and by gas : chromatography/mass spectrometry(GC/MS). More than forty peaks were observed in the CG(FID) profile. and more than ten peaks were observed in the GC(NPD) profile. Among them, thirteen components 1including one aldehyde, four hydrocarbons, two esters, folly alcohols, and two vyrazines were identified: six components the molesuiar ions of which were m/z, 204 were estimated to be a series of azulene compounds; and the other components unidentified were estimated to have molecular weights of lower than 254. Therefore, the freeze-drying technicue is thought to be usefu1 for the isolation of volatile compounds of such low molecufilar weights from vegetables, fruits and biological fluids as well as fresh ginseng roots under the tested conditions.

• Journal of Microbiology and Biotechnology
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• 제32권12호
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• pp.1599-1604
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• 2022

Storage stability of freeze-dried lactic acid bacteria is a critical factor for their cost-effectiveness. Long-term storage of lactic acid bacteria enables microbial industry to reduce distribution costs. Herein, we investigated the effect of cold adaptation under supercooling conditions at -5℃ on the viability of Leuconostoc mesenteroides WiKim32 during the freeze-drying process and subsequent storage. Cold adaptation increased the thickness of exopolysaccharides (EPS) and improved the viability of freeze-dried Leu. mesenteroides WiKim32. Compared to non-adapted cells, cold-adapted cells showed a 35.4% increase in EPS thickness under supercooling conditions. The viability of EPS-hydrolyzed cells was lower than that of untreated cells, implying that EPS plays a role in protection during the freeze-drying process. Cold adaptation increased the storage stability of freeze-dried Leu. mesenteroides WiKim32. Fifty-six days after storage, the highest viability (71.3%) was achieved with cold adaptation at -5℃. When EPS-containing broth was added prior to the freeze-drying process, the viability further increased to 82.7%. These results imply that cold adaptation by supercooling pretreatment would be a good strategy for the long-term storage of Leu. mesenteroides WiKim32.

• 한국식품과학회지
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• 제21권1호
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• pp.13-16
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• 1989

선택된 당류 및 전분 가수분해 물질을 기질로 사용하여 냉동건조에 의하며 acetaldehyde을 고정시키는 방법을 연구하였다. 단순기질 보다는 복합기질이 일반적으로 acetaldehyde를 고정시키는 능력이 좋았고. 특히 mannitol+lactose가 고정능력 면에서 가장 우수했다. 그리고 경계성 등을 고려할 때 mannitol+maltodextrin이 공업적으로 acetaldehyde를 고정하는데 적당할 것으로 평가됐다. 일반적으로, 기질 농도가 증가함에 따라 건조 중 acetaldehyde손실이 감소하였으며, 기질 농도 40%일 때 mannitol+maltodextrin 기질의 acetaldehyde 고정 능력이 가장 좋았다. 냉동건조 방법으로 acetaldehyde를 고정할 경우 건조실 압력이 낮을수록 건조 중 acetaldehyde 손실이 감소했다. 그러나 대량생산을 목적으로 할 때에는 0.5 Torr이하의 압력을 유지하는데 건조경비 부당이 과다하므로, 0.5 Torr정도의 건조실 압력을 유지하는 것이 적당할 것으로 평가됐다.

• 한국식품영양학회지
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• 제33권1호
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• pp.64-73
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• 2020

The purpose of this study was to investigate the antioxidant activity and β-glucan content of extracts extracted by varying the temperature at 30, 55 and 80℃ after hot air drying or freeze drying of Pleurotus ostreatus and Pleurotus eryngii. For the analysis antioxidant activity of each mushroom, β-glucan, total phenol, flavonoid contents, and DPPH·ABTS⁺·Nitrite assay were measured. Also, the β-glucan content, total flavonoid content and ABTS⁺ scavenging activity increased with freeze drying rather than hot air drying, and increased with increasing extraction temperature in both mushrooms. However, the total phenol and nitrite scavenging activity increased with hot air drying rather than freeze drying, and decreased with increasing temperature in both mushrooms. DPPH scavenging activity was not significant in both mushrooms, but decreased with increasing extraction temperature. Pearson's correlations between total flavonoid content and antioxidant activities were r=0.719~0.753 (p<0.01). As a result, the β-glucan content, total flavonoid content, and ABTS radical cation scavenging activity were highest during freeze drying and extraction at 80℃. And the highest total phenol content, DPPH radical scavenging activity and nitrite scavenging activity were obtained during hot air drying and extraction at 30℃.

• 한국식품과학회지
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• 제38권2호
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• pp.188-196
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• 2006

생식 제조공정 중 주요공정인 건조방법에서 효율적인 방법을 찾기 위하여 건조방법에 따른 생식 원료 이화학적 특성 및 기능성 성분의 변화를 조사하였다. 당근, 양배추, 표고버섯, 양송이버섯, 미역 김의 단백질, 지방, 탄수화물, 회분 등 성분의 함량은 열풍건조(50, 55, $60^{\circ}C$) 및 동결건조를 통하여서는 거의 변화가 없는 것으로 나타났다. 당근, 표고버섯, 미역은 열풍건조 및 동결건조를 실시한 후 변화가 없는 것으로 관찰되었고 양배추(a값), 양송이버섯(L, a, b값), 김(a값)의 변화가 있는 것으로 나타났다. 식이섬유의 함량은 열풍건조를 거친 시료에서 증가를 나타냈다. 당근, 양배추, 미역, 김 중의 Vitamin C와 ${\beta}-carotene$ 함량은 열풍건조를 진행한 시료가 동결건조를 진행한 시료보다 손실이 많이 것으로 나타났고 총 페놀성 화합물과 lectin의 함량은 열풍건조 및 동결건조를 거쳐도 거의 변화가 없는 것으로 나타났으며 pectin, alginic acid, porphyran 등의 함량은 열풍건조를 실시한 시료에서 증가를 나타냈다. 총 페놀성 화합물, lectin pectin, alginic acid, porphyran과 같은 기능성 물질을 함유한 생식 원료는 열풍건조방법을 이용하는 것이 경제적일 것으로 생각되며 Vitamin C와 ${\beta}-carotene$과 같이 열에 약한 비타민을 많이 함유한 생식 원료는 동결건조 방법을 사용하는 것이 바람직할 것으로 생각된다.

• Archives of Pharmacal Research
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• 제29권8호
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• pp.707-711
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• 2006

Bifidobacteria-loaded alginate poly-l-lysine microparticles (bap microparticles) were prepared using an air atomization method and then freeze-dried. The viability of the bap microparticles was investigated as a function of the amount of the bifidobacteria cultures, and the addition of a yeast extract, cryoprotectants, antioxidants and neutralizer. The size of the bap microparticles with and without the bifidobacteria was $84.8{\pm}28.5\;{\mu}m$ ($mean{\pm}standard$ deviation) and $113.1{\pm}38.5\;{\mu}m$, respectively. The surface morphology was slightly ellipsoid and wrinkled regardless of the incorporating bifidobacteria. The viability gradually decreased with increasing freeze-drying time. Free-flowing powdered bap microparticles were obtained at least 12 h after freeze-drying the wetted slurry of bap microparticles. However, the particles tended to aggregate when either lactose or ascorbic acid was added. The addition of a yeast extract, cryoprotectants (glycerol and lactose), antioxidants ($NaHSO_3$ and ascorbic acid) and neutralizer $(Mg_3(PO_4)_2)$ resulted in a significantly higher viability of the bifidobacteria in the bap microparticles after freeze-drying (0.34-1.84 log) compared with the culture alone.