• ALGAE
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• v.21 no.1
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• pp.125-131
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• 2006

Long-term preservation of bloom-forming cyanobacteria was evaluated using cryopreservation and freeze-drying of nine strains belonging to four genera and seven species. All test strains, except Aphanizomenon flos-aquae NIER- 10028, showed partial or complete survival following cryopreservation and freeze-drying. Frozen and freeze-dried strains were preserved for more than two years and were revived monthly. Most strains showed higher post-thaw viability after cryopreservation, especially without cryoprotectant compared to freeze-drying. Microcystis aeruginosa NIER-10010, M. viridis NIER-10020, M. ichthyoblabe NIER-10023, M. novacekii NIER-10029 and Oscillatoria sancta NIER-10027 were revived after 2.5 years of cryopreservation. These results suggest that cryopreservation may be an easy and timesaving long-term preservation method for bloom-forming cyanobacteria.

• Korean Journal of Food Science and Technology
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• v.27 no.3
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• pp.380-386
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• 1995

An attempt was made to determine the effects of drying methods including shady air drying, presteamed and shady air drying, microwave drying, and freeze drying on the volatile flavor components with Commelina communis L.. Essential oils from the samples were isolated by simultaneous steam distillation-extraction(SDE) method using diethyl ether as solvent. Concentrated samples were analyzed by gas chromatography(GC) and combined gas chromatography-mass spectrometry(GC-MS). Respective 29, 47, 36, and 24 volatile flavor components were identified in shady air dried samples, presteamed and shady air dried samples, microwave dried samples, and freeze dried samples. The kinds and amounts of volatile flavor components were evidently depended upon the drying methods. 6,10,14-trimethylpentadecanone was regarded as the most abundant component in shady air dried samples, 6,10,14-trimethyl-2-pentadecanone in presteamed and shady air dried samples, neophytadiene in microwave dried samples, and ethyl acetate in freeze dried samples.

• Journal of Life Science
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• v.31 no.7
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• pp.617-625
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• 2021

To enhance the applications of apple pomace, which is a by-product of apple, this study analyzed the nutritional components, ursolic acid content, and antioxidant activity of different solvent (distilled water, fermented alcohol, and methanol) extracts. The samples included hot air-dried and freeze-dried apple pomace. The moisture, protein, fat, ash, and total dietary fiber contents of hot air-dried apple pomace were 3.2%, 3.9%, 2.4%, 2.0%, and 28.5%, respectively, and those of freeze-dried apple pomace were 8.2%, 3.4%, 2.4%, 1.8%, and 33.0%, respectively. Ursolic acid was not detected in the distilled water extract of either sample. However, in hot air-dried apple pomace, the methanol extract was 1,753.32 ㎍/ml, and the fermented alcohol extract was 1,532.94 ㎍/ml. In freeze-dried apple pomace, the methanol extract was 1,407.04 ㎍/ml, and the fermented alcohol extract was 1,221.81 ㎍/ml. The total polyphenol and flavonoid contents were 306.7 ㎍/ml and 950.1 ㎍/ml, respectively in methanol extracts of hot air-dried apple pomace and 277.6 ㎍/ml and 925.0 ㎍/ml, respectively in methanol extracts of freeze-dried apple pomace. 2, 2'-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities of hot air-dried apple pomace were 73.3% in methanol extract and 59.4% in fermented alcohol extract, and those of freeze-dried apple pomace were 76.1% in methanol extract and 66.0% in fermented alcohol extract. Both samples had the lowest antioxidant activity in distilled water extracts. Similar to DPPH radical scavenging activity, both samples showed increasing 2,2'-azino-bis(3-ethylbenzothiazoline-6- sulfonic acid) (ABTS) radical scavenging activity in the order of methanol, fermented alcohol, and distilled water. All samples had stronger reducing power than ascorbic acid (311.5 ㎍/ ml) as a positive control.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.3
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• pp.221-228
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• 2001

This study was carried out to investigate the effect of germination condition and drying temperature on growth and physicochemical properties of brown rice. Three brown rice seeds of Ilpumbyeo, Dasanbyeo and Heugjinjubyeo were stored at room temperature for six weeks to test the time-sequence germination viability. Relatively stable germination ratio was maintained until 2 weeks after storage. However, 3 weeks after storage, germination ratio of brown rice seeds started to decrease rapidly and their germination ratio was lower than 80%. For this reason, brown rice was recommended for seeding within 2 weeks after hulling. During the initial 5 days, germination ratio of 24 hours pre-soaking brown rice was higher about 2-3% than that of non-soaking brown rice. The $25^{\circ}C$ was considered as the most favorable temperature for brown rice germination, because of the high germination ratio and desirable coleoptile growth of the brown rice, and little seed rotting symptoms. The scanning electron micrographs showed the structural differences between hot-air dried and freeze dried germinated-brown rice kernel. In the freeze dried germinated-brown rice, seed coat (pericarp, tegmen and aleurone layer) was mechanically disrupted from the endosperm, and many cleavages were observed among starch storing cells and starch granules. The endosperm of freeze-dried brown rice kernels formed the sponge-like structures and showed the fragile traits. For this reason, hot-air drying is considered as more suitable method than freeze drying for germinated-brown rice. The crude protein and amylose contents were slightly changed, but there were no significant differences during the germination period. Crude fiber content was decreased, but crude Int and total amino acid contents were increased as seeding days increased. A rapid increase in $\alpha$-amylase activities of germinating brown rice was observed at S days after seeding, and $\alpha$-amylase activities were decreased from 8 days after seeding. Total free sugar contents were decreased during the germination period. There was continuous decline in the contents of sucrose and glucose until 8 days after seeding, but fructose and maltose content were gradually increased from the 5 days after seeding.

• Journal of Radiation Industry
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• v.6 no.4
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• pp.299-304
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• 2012

The quality properties of freeze-dried apples, pears, strawberries and pineapples gamma-irradiated at 0, 1, 2, 3, 4, and 5 kGy were evaluated to develop germ-free products for immuno-compromised patients. The initial count of total aerobic bacteria in non-irradiated apples, pears, strawberries and pineapple was 2.5, 3.1, 2.6, and $3.2{\log}\;CFU{\cdot}g^{-1}$, respectively. Microorganisms were not observed in apples after 1 kGy, in pears and strawberries after 4 kGy, and in pineapples at 5 kGy within a detection limit of $10{\log}\;CFU{\cdot}g^{-1}$. In addition, the sterilization of each sample was confirmed at the same dose. The score for the overall acceptance of freeze-dried fruit irradiated at a sterilization dose was 5.5 for apples, 4.1 for pineapples, and 4.0 for the other fruits, whereas that of non-irradiated control sample was 5.6 for apples, 5.2 for pears, and 5.8 for strawberries and pineapples with a 7-point scale. As a result, gamma irradiation of 1 kGy for apples, 4 kGy for strawberries and pears, and 5 kGy for pineapples is sufficient to sterilize each freeze-dried fruit with acceptable sensory properties.

• Korean Journal of Food Science and Technology
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• v.32 no.4
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• pp.881-888
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• 2000

Lactic acid bacteria(LAB) fermented food was prepared with milk or egg white powder(EWP) and added with freeze drying protectant(FDP). 0.2% of Tween 80 or 1% of ascorbate was added to milk sample and 3% of raffinose or 1% of ascorbate was added to EWP sample. Effects of FDP on sensory property, volatile aroma compounds and physical property of LAB fermented food were investigated. In case of non-freeze dried samples, sensory properties of milk sample with ascorbate were slightly better than those of reference sample(milk), while sensory properties of EWP sample or EWP sample with FDP were slightly inferior to reference sample. Sensory properties of all of the freeze dried/reconstituted samples were not different. Sensory properties of milk sample with ascorbate were reduced by freeze drying/reconstitution, while those of sample with ascorbate were not changed. Although all of the volatile aroma compounds were reduced by freeze drying, the residual ratio was slightly different between milk samples and EWP samples. Difference in volatile aroma compounds between milk samples and EWP samples before freeze drying was relatively large, while difference between two sample groups after freeze drying/reconstitution was relatively small. Rheological properties of milk samples were markedly changed by freeze drying/reconstitution, while those of EWP samples were changed slightly.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.5
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• pp.695-701
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• 2015

This study was conducted to evaluate the effects of drying and extraction methods on antioxidant activity and total phenol content of Gnaphalium affine D. DON (GA). Hot-air, shade-drying, and freeze-drying were used for drying, after which magnetic stirring and ultrasonification were applied. Extracting solvents were water, 80% ethanol, and 80% methanol. Total phenol content was highest in 80% ethanol extract of freeze-dried and stirred GA. Total flavonoid content was highest in 80% methanol extract of freeze-dried and stirred GA. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity was higher in 80% methanol and 80% ethanol extracts than in water extract. 2,2-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity was highest in 80% ethanol extract of shade-dried and ultrasonicated GA. Reducing power was generally higher in 80% methanol extract than in 80% ethanol and water extracts of GA. Total phenol and total flavonoid contents were highly correlated with DPPH radical scavenging activity and reducing power, respectively. This result implies that the antioxidant activity of GA can be attributed to phenol compounds such as flavonoids. Conclusively, phenol compounds such as flavonoids are responsible for the antioxidant activity of GA, and there was no significant effect of drying and stirring conditions on antioxidant activity of 80% ethanol. Meanwhile, DPPH radical scavenging activity of water extract and reducing power of 80% methanol extract were higher in hot-air and shade-dried GAs than in freeze-dried GA.

• Korean Journal of Food Science and Technology
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• v.30 no.1
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• pp.139-145
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• 1998

This study was performed to provide fundamental data on the optimum manufacture condition of oleoresin using citron peel. Oleoresin was extracted from freeze-dried or hot air dried citron peels using various solvents (hexane, ether, dichloromethane, acetone. and methanol), mixing ratio, extraction temperature, and time. As a result, optimum extraction conditions of oleoresin were: solvent mixing ratio 1:10 (w/v), extraction time 2 hours, and extraction temperature $60^{\circ}C$ when used methanol, and their dichloromethane 1:10 (w/v), 4 hours and $20^{\circ}C$, respectively. At optimum extraction conditions, the yield of oleoresin was shown that 35.79% at hot air drying samples, 32.04% at freeze-dried ones when extracted by methanol, but shown 5.86% and 6.16% when used dichloromethane respectively. The number of volatile components present in citron oleoresin were confirmed as thirty two in methnol extracion method and twenty nine in dichloromethane extraction method by GC and GC/MS, respectively. But, in the kinds and amounts of volatile flavor components, relatively greater numbers of volatiles were identified in freeze-dried sample extracted by dichloromethane compared with other methods. In freeze-dried sample extracted by dichloromethane, volatile components of citron oleoresin predominantly occupied by limonene and ${\gamma}-terpinene$ with about 85%. Other important compounds were shown hydrocarbons. such as ${\alpha}-pinene$, myrcene, terpinolene, ${\beta}-farnesene\;and,\;{\delta}-elemene$, and linalool as alcohols.

• Korean Journal of Food Science and Technology
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• v.34 no.5
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• pp.805-810
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• 2002

Development of tenderizer using domestic fruits was studied. Kiwifruit was dried using various methods, and the quality of kiwifruit powder was observed during 12 week storage. Frozen kiwifruit was prepared in paste, dice, and whole flesh. After drying, paste-type kiwifruit showed 2.0 and 1.3 times higher proteolytic activity than dice and whole flesh kiwifruits, respectively. Nine hour of hot-air drying or 46 h of freeze-drying eliminated more than 90% of water from kiwifruit, during which discoloring of kiwifruit occurred. Freeze-dried powder showed 6.6 times higher yield and proteolytic activity, and resulted in almost no discolorization than those of air-dried powder. Addition of bulking agent affected the quality of hot air-dried kiwifruit powder, except color, resulting in $3.2{\sim}3.6$ times higher proteolytic activity than that without bulking agent, which is comparable to 60% of the initial freeze-dried powder content. Moisture content of kiwifruit powder with bulking agent sustained consistently during 12 week storage, whereas proteolytic activity decreased for the first 4 weeks. Freeze-drying is a preferable method to produce kiwifruit powder for tenderizer, although hot air-drying with bulking agent treatment is more economical.

• The Korean Journal of Nuclear Medicine Technology
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• v.16 no.2
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• pp.139-148
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• 2012

Purpose : Since standard solution is the one that knows its exact concentration, the curve of the dissolution has been determined according to the amount of the solution, compared to the amount of the unknown sample. Therefore, the antigen that makes up standard materials should be made in a pure form. The configuration of the standard substance solution in the kit we use is a freeze-dried material, or made and comes as a liquid. Lyophilized reference material is used after dissolving in usually D.W. (Distilled Water), and if the antigen to use is too sensitive, reagents should be freeze-dried. Furthermore, when freeze-dried reference has to be frozen again after being dissolved, it should be kept under $-20^{\circ}C$ until the expiration date according to the reports. Since it is not expressed in the experiment if it is safe or stable to reuse the solution which was dissolved a few times, thus, this time it is tested and evaluated that the changes of the standard solution by freezing and melting several times, and its results and the effectiveness of it were compared to the solution which was kept in a fridge. Materials and Methods : Among Vitro diagnostic kits on the market made by radioimmunoassay, parathyroid hormone (PTH), adrenocorticotropic hormone (ACTH), luteinizing hormone (LH) are made of freeze-dried standard solution and all composed of the same Lot.NO. These hormones melted in D.W. and were separated into three groups. In the first group, melting and freezing were repeated, and in the second group, The solution only for one time use was put into a test tube after melting and freeze it. The third group was kept in the refrigerator. This experiment has been conducted from January to February in 2012. January to 2012. PH test was employed because ph is prone to changing depending on the change of protein. Each group of the standard solution, cpm (counter per minute), and the patient relative concentration values were compared by date, and Through the correlation coefficient and Paired t-test, the significant level of each group was analyzed. Results : ACTH, PTH, LH pH values were too subtle denaturation rather than numerical changes in the protein. In addition, when the standard solution of ACTH, PTH, LH was refrigerated, after 3 days and 7 days, there was a significant difference observed between the solution being kept in a refrigerator and a freezer within a significance level. Conclusion : Standard solution should be kept in a freezer, and being kept in a fridge, it is recommended to use the solution as soon as possible.