• Korean Journal of Food Science and Technology
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• v.26 no.2
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• pp.147-151
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• 1994

Hydrogen donating activities(HDA) of solvent extracts of Hololeion maximowiczii roots which were treated with freeze drying, hot air drying and hot air drying after steam blanching were investigated by the method of ${\alpha},{\alpha}'$-diphenyl-${\beta}$-picrylhydrazyl(DPPH). Hydrogen donating activity of hot air drying after steam blanching group showed the highest activity among three drying methods. Among the extracts of freeze dried root extracted with various solvents, color intensity at 420 nm of aqueous extract was highest, but hydrogen donating activity was shown in order of 50%, ethyl alcohol, methyl alcohol, water extracts. By heating the powder of freeze dried root at $100^{\circ}C$, color intensity of its water extract was decreased until 20 min, thereafter it was increased slowly but hydrogen donating activity was rapidly increased until 30 min. Hydrogen donating activity at the concentration of 6.05 mg/ml of 50% alcohol extract was similar to that of ${\alpha}-tocopherol$ at the concentration of $2{\times}10^{-4}M$. Comparison of hydrogen donating activity of the inner and outer solution after dialysis of water extract showed that the outer solution had a stronger hydrogen donating activity than those of the inner one.

• Korean Journal of Medicinal Crop Science
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• v.22 no.4
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• pp.255-261
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• 2014

Cosmetic activities of the leaves of Curcuma longa L. were compared according to different drying methods, to expand the use of the by-products of Curcuma longa L. The highest extraction yield of 29.4% was obtained from vacuum drying process (VD), whose value was very close to 29.2% from freeze drying process (FD). Relatively lower extraction yield were observed as 24.5% and 25.3% from the raw leaf (RL) as control and hot air drying process (HD). The cytotoxicity was observed lower FD and VD than RL and HD. It shows that cytotoxicity was closely related to cosmetic activities such as tyrosinase and melanin inhibition activities by showing much better cosmetic activities of the extracts from both FD and VD than those from the RL and HD. It was interesting that was differences of the cosmetic activities and cytotoxicity between FD and VD, which implies that VD method should be a more efficient process than FD method in terms of drying time and operation costs: 6 hours vs 24 hours and 3-5 times higher extraction costs in drying. It was observed that VD is more excellent dry method than others. This result could be utilized to effectively dry other soft plant biomass.

• Food Science and Preservation
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• v.15 no.4
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• pp.524-531
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• 2008

To investigate tea prepared from Ixeris dentata root, color, and levels of free sugars, organic acids, cynaroside, total polyphenolics, and free amino acids were investigated using various thermal processing methods. These included natural drying(ND), hot-air drying(HAD, $75^{\circ}C$), hot-air drying after steam(HADS, steaming at $95^{\circ}C$ for 30 min) and roasting after hot-air drying(RHAD, roasting at $140^{\circ}C$ for $2{\sim}3$ min). Total free sugars, organic acids, cynaroside, and free amino acids contents were highest after ND treatment. Total polyphenolics was highest after RHAD processing. The level of cynaroside, a principal component of Ixeris dentata root, was significantly decreased by HADS. The major free sugars were fructose, glucose and sucrose. Succinic acid was prominent among organic acids, and was present at 2.25%(v/v) after ND treatment. The lightness(L), redness(a), and yellowness(b) of all dried Ixeris dentata root powders were best after RHAD treatment, but analysis of the leaching liquids after hot water treatment yielded variable results. Lightness and redness were the highest after RHAD and yellowness was the highest after ND treatment. Overall, the RHAD drying method was found to be superior to other methods, in sensory evaluation tests.

• Korean journal of food and cookery science
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• v.27 no.1
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• pp.75-84
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• 2011

The aim of this study was to develop a convenient brown sauce product with long shelf life that has similar taste and quality characteristics with sauce used in restaurants. Response surface analysis was carried out to optimize brown sauce. Extracted brown sauce powder was subjected to hot air drying, infrared drying, freeze drying, and spray drying to determine the appropriate drying method for brown sauce manufacturing. The optimum extraction conditions were set by superimposing and reading each reaction surface that satisfied all of the sensory characteristics such as color, smell, taste, concentration, and overall preference level in order to set the optimum conditions for brown sauce production. The optimum extraction conditions for brown sauce were determined to be heating time 30 min, gelatin addition quantity 9.00%, and tomato paste addition quantity 11.25%. Reliability test showed a similar value to the predicted scope when compared to the experimental value obtained under the same conditions as the predicted value according to RSM (response surface methodology), enabling verification of the derived regression formula. Product powder of ideal brown sauce by heating, infrared radiation, freezing, and spray drying and investigate result for functional tests of color, flavor, taste, viscosity, overall acceptability and show highly acceptability on powder by infrared rays and freeze-drying methods. Especially, infrared radiation method resulted in favorable color and flavor values while freeze-drying method produced good taste and viscosity values and high overall acceptability. Therefore, infrared radiation drying method and freeze-drying method to product powder.

• Korean Journal of Food Science and Technology
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• v.40 no.4
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• pp.466-469
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• 2008

This study examined the effect of drying temperature on the qualitative properties of Chrysanthemum boreale M. flowers. The flower samples were dried in a hot air dryer at $40^{\circ}C$, $50^{\circ}C$, and $60^{\circ}C$, respectively, to attain a $23{\pm}1%$ moisture content. The time required to reach the target moisture content was 8.5-69 hr, and there was a very high negative correlation between log (spending time) and temperature. The Hunter color L- and b-values of the flowers were decreased with increasing drying temperature, whereas the a-value was increased. The volatile compounds contained in the dried flowers were determined by a solid-phase microextraction method. Twelve primary volatile compounds were detected and then quantified based on the GC chromatograms of the samples. The total contents of volatile compounds were increased with increasing drying temperature, and germacrene D and camphor were the main compounds in all samples.

• 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.

• Food Science and Preservation
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• v.9 no.1
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• pp.36-41
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• 2002

We examined the chemical properties of leek and dropwort and prepared the noodles with the dried powder of them, to develope functional processing floods which contain biological active compounds. The groups were divided by the drying methods as follows: hot air drying at 50$\^{C}$ (A), hot air drying after blanching for 30 sec (B), hot air drying after steaming for 2 min (C) and freeze drying (D). We had analyzed the content of vitamin C, total chlorophyll, and phenolic compounds and measured the hunter color values of dried powders individually. The contents of evaluated compounds were higher in A and D than in B and C groups and also the electron donating activity of A and D was stronger than B and C. The cooking properties of noodles prepared with leek and dropwort powder were examined. After cooking, the weight and volume of noodles prepared with powder were lower than those of control The turbidity of noodle soup were increased as the adding ratio was increased. The cutting strength of cooked leek noodles with A and B powder was similar to that of control, in case of dropwort, cooked noodles with D showed similar to that of control. The cutting strength of cooked noodles were decreased as the adding ratio were increased. The electron donating activity of noodles with vegetable powders showed high than that of control The sensory evaluation showed that significant difference between noodles with 2.5 ?/e addition groups and control was not recognized but was recognized between noodles with 5% addition groups and the control.

• The Korean Journal of Food And Nutrition
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• v.34 no.2
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• pp.165-173
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• 2021

Centella asiatica (CA) has been used as a nutritional plant as well as a traditional herbal medicine around the world. This study, quality component (proximate composition, total polyphenol, and triterpenoid compound), and antioxidant and anti-inflammatory activities of CA dried using various methods were investigated. Proximate compositions of CA with different drying methods included a large amount of carbohydrates, crude protein, crude ash, and crude fiber. Among the drying methods, cold drying provided the highest total polyphenol content and antioxidant activity, while hot-air drying at 75℃ provided the lowest total polyphenol content and antioxidant activity. In addition, when the major triterpenoid compounds of CA were analyzed, the highest content of asiaticoside of triterpenoid glycoside was obtained with all drying methods. With respect to the total triterpenoid, the highest content was obtained with cold drying (68.8 mg/g) whereas natural drying (31.4 mg/g) provided the lowest content. In anti-inflammatory activity of LPS-stimulated RAW 264.7 cells, EtOH extract of cold drying showed a significantly higher inhibitory activity in comparison to the other drying methods. In conclusion, it is considered that the cold drying method is suitable for industrial preparation of functional materials with high physiological ingredients, and antioxidant and anti-inflammatory activities from CA.

• Food Science and Preservation
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• v.31 no.2
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• pp.218-226
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• 2024

The oriental melon poses challenges in terms of long-term storage and distribution. Addressing these issues requires an extension of the storage life through appropriate processing. In this study, pretreated hot-air dried oriental melon slices (steamed and freeze-thawed) were prepared, and their physicochemical and organoleptic properties were examined. The control group (CON) consisted of hot-air dried oriental melon slices without pretreatment, while the steamed group (STG) and freeze-thawed group (FTG) consisted of hot-air dried oriental melon slices pretreated using steaming and freeze-thawing methods, respectively. The moisture contents detected in the CON, STG, and FTG groups ranged from 15.96% to 27.30%, with variations of 7.53 to 8.40 °Brix for the soluble solid contents. The CON group showed the highest Hunter color value for lightness (L^*) and the lowest value for redness (a^*). The texture profile analysis revealed the highest hardness and chewiness in the order of STG > CON > FTG. Considerable differences were observed in springiness and adhesiveness in the FTG group compared to the other groups. The organoleptic evaluation showed that the CON group had the highest sensory scores for overall preference. These findings indicate that the properties of hot-air dried oriental melon slices were influenced by physical pretreatments and that manufacturing these slices without pretreatment is the most effective method in terms of processing simplicity and cost efficiency.

• Journal of Power System Engineering
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• v.21 no.4
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• pp.62-69
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• 2017

Because the moist foods like anchovy were appeared lower quality by hot air that occurred the lipid oxidation, the drying system by using the cold air has been used widely. This study has been carried out on the performance improvement according to arrangement angle of baffle and location of air duct in the cold air dryer. The main parameters in this study are the arrangement angles which are without, $0^{\circ}$, $10^{\circ}$, $20^{\circ}$, $30^{\circ}$ and $40^{\circ}$, and the locations of air duct are without, front, center and back. For this study we have conducted the numerical analysis method using fluent in order to obtain the optimal condition of the drying performance. As the arrangement angle of baffle is increased, the relative humidity is proportionally decreased, the value at $40^{\circ}$ is 42.2% that indicate the reduction of about 4% than without it. After the air duct was installed, the decreased relative humidity is showed within 1%, therefore, the effect of air duct for improving the dry capacity is more large than the arrangement angle of baffle. Finally, we have obtained the optimal conditions that the arrangement angle is $40^{\circ}$ with the air duct for a cold air dryer.