• Korean Journal of Food Science and Technology
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• v.31 no.3
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• pp.625-630
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• 1999

This work was to study drying characteristics of the brown rice koji, an enzymic health food, using microwave under vacuum. Cooked brown rice was inoculated with Aspergillus oryzae and incubated at $32^{\circ}C$ for 6 days. The brown rice koji was dried by different drying methods: microwave vacuum drying, hot air drying, vacuum drying and freeze drying. Each drier except freeze drier was set to maintain the sample temperature at $40^{\circ}C$. During microwave vacuum drying, the sample reached $40^{\circ}C$ much faster (within $5{\sim}10\;min$) and was dried much faster (2 hrs) than the other drying methods. The initial drying rate of microwave vacuum drying was ten times faster than that of hot air drying. The microwave vacuum drying produced a dry sample of the highly retained enzymic activity, followed by freeze drying, vacuum drying, and hot air drying.

• Korean Journal of Food Science and Technology
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• v.20 no.3
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• pp.380-384
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• 1988

The coefficients of the hot-air and freeze dried garlic isotherms and the critical water activities of these were estimated to be 0.85-0.94 by the linear regression and 0.58-0.60 by the sensory evaluation and ${\Delta}E$ value. Water adsorption rate(K) of hot-air dried garlic packaged with $48{\mu}m$ low density polyethylene(LDPE) decreased from $0.12g\;H_2O/100g/day\;to\;0.093g\;H_2O$/100g/day with decreasing the package dimension from $0.051m^2\;to\;0.029m^2\;at\;40^{\circ}C$ and 75% RH, and that of freeze dried one decreased from $0.17g\;H_2O/100g/day\;to\;0.12g\;H_2O$/100g/day as the filling weight increased from 50g to 10g in the package of $0.051m^2$. Shelf-life of hot-air dried garlic packaged with $80{\mu}m$ LDPE were 99days at $40^{\circ}C,\;283day\;at\;30^{\circ}C\;and\;455\;days\;at\;15^{\circ}C$ in the 75% RH. The differences of water contents between predicted data with water vapor permeability of the conventional method and experimental data were 0-1.5% in the water content range of around 13-18%, but about 2 in the water content range of around 8-11%.

• Korean Journal of Food Science and Technology
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• v.30 no.5
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• pp.1107-1113
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• 1998

This work was to study the potential use of germinated and microwave-vacuum-dried brown rite as a raw material for enzyme food. Brown rice was soaked in water at $15^{\circ}C$ for 2 days and then germinated at $25^{\circ}C$ for 4 days. The germin ated brown rice was then dried by different drying methods: microwave vacuum drying 1(drying only), microwave vacuum drying 2 $(drying{\rightarrow}crushing{\rightarrow}drying)$, hot air drying, vacuum drying and freeze drying. Each drier except freeze drier was set to maintain the sample temperature to be $60^{\circ}C$. During microwave vacuum drying 1 and 2 the sample reached $60^{\circ}C$ much faster (5 min) and was dried much faster (2 to 3 hrs for microwave vacuum drying 1 and 2 than the other drying methods. The initial drying rate of microwave vacuum drying was ten times faster than that of hot air drying. The microwave vacuum drying produced a dry sample of the highly retained enzymic activity, followed by freeze drying, vacuum drying and hot air drying.

• Korean Journal of Food Science and Technology
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• v.35 no.3
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• pp.393-398
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• 2003

Effects of convection oven dehydration conditions on the physicochemical and sensory properties of ginkgo nut powder were examined using three types of pre-treatment on ginkgo nuts: coarse grinding of ginkgo nut (GR); coarse grinding followed by 1 min blanching (GB); 3 min blanching followed by coarse grinding (BG). Pretreated ginkgo nuts were dried in convection oven at 70 and $80^{\circ}C$ to the moisture content of approximately 5%. Rehydration rate, swelling power, solubility, lightness, and greenness of GB ginkgo nut powder dried at $70^{\circ}C$ were the most similar to those of freeze dried one. GR and GB samples dried at $70^{\circ}C$ had higher sensory values of green color and ginkgo nut flavor. Ginkgo nut powder with desirable quality attributes could be produced by drying GB in convection oven at $70^{\circ}C$ for 10 hr.

• Food Science and Preservation
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• v.23 no.6
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• pp.819-824
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• 2016

The changes in physicochemical characteristics and sensory evaluation of bracken (Pteridium aquilinum) and Aster scaber dried by different methods sun-dried, hot-air-dried and freeze-dried were investigated. The freeze-dried Aster scaber showed the lowest moisture content than those of sun-dried and hot-air-dried. Freeze-dried bracken and Aster scaber showed higher rehydration rate than sun-dried and hot-air-dried. In the color values, the freeze-dried bracken and Aster scaber had the highest $L^*$ value of 29.48 and 32.73, respectively, while freeze-dried Aster scaber showed the lowest $a^*$ value of -6.78. Rehydrated bracken and Aster scaber after freeze-dried were the highest value in $L^*$ and $b^*$, while the lowest in $a^*$ value. In sensory evaluation, freeze-dried bracken and Aster scaber showed the highest in color, appearance, flavor, texture and overall acceptability. There were no significant differences in texture between hot-air-dried bracken and freeze-dried bracken after rehydrating. However, freeze-dried bracken and Aster scaber were the highest in color, appearance, flavor and overall acceptability. In conclusion, freeze-dried bracken and Aster scaber showed the best rehydrated rate, color and sensory properties.

• Korean Journal of Medicinal Crop Science
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• v.4 no.4
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• pp.308-313
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• 1996

The appropriate drying method in medicinal compounds and color of peony root was that predrying at briquet fire $(40{\sim}60^{\circ}C)$ for 6 hours or more, and then hot air drying at $40^{\circ}C$ during 60 hours. But this method needs too much time in drying. And the method that drying at $40^{\sim}C$ with hot air drying has bad result in color. In case Peony was seld by cutting product, before cutting, the Peony root was retted for 30 min. and sealed for 12 hrs. is good for drying time, Peoniflorin content and commodity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.12
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• pp.1948-1953
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• 2014

This study examined changes in antioxidant activity as well as contents of rosmarinic acid, homoplantaginin, and luteolin, which is the main substance of Salvia plebeia R. Br. (SPR) known to have anti-inflammatory efficacy, according to drying, blanching, and fermentation conditions. Rosmarinic acid content was 16.42 mg/g upon hot-air drying and 10.19 mg/g upon hot-air drying after blanching, and there was no significant difference in the case of leaf and root freezing or cold-air drying. Rosmarinic acid content was 8.69 and 8.15 mg/g in the case of air-drying in the shade and freeze-drying, respectively, and decreased to 0.05 mg/g or undetected after fermentation. SPR processed by freeze-drying, cold-air drying in the shade, and hot-air drying showed ABTS radical scavenging ability over 98.5% at a concentration over $500{\mu}g/mL$ as well as excellent radical scavenging ability of 87.3% in the case of hot-air drying after blanching. Root showed lower ABTS radical scavenging ability than leaves. SOD-like activity was measured to be 6.1~27.8% at a concentration of $1,000{\mu}g/mL$, which was significantly difference from ABTS radical scavenging ability. As rosmarinic acid and homoplantagine, an anti-inflammatory material contained in SPR, are almost undetectable after oxidation fermentation during processing, hot-air drying after blanching or drying seems to be suitable to develop SPR as a functional substance.

• Culinary science and hospitality research
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• v.19 no.3
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• pp.73-86
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• 2013

This study produced hot-air-dried perilla leaf to add Korea's popular perilla leaf to fresh noodles to examine their value as food and get the best fresh noodle recipe by adding 0%, 3%. 6%, 9%, and 12% of perilla leaf to flour. The moisture content of the dough was highest at 34.41% for the control group with 0% perilla leaf, whereas the pH was lowest at 5.59 for the dough with 12% perilla leaf. As a result of WRC analysis of the dough, moisture absorption increased with greater perilla leaf content. The moisture content of fresh noodles was lowest for the control group with 0% perilla leaf, whereas the pH was highest for the control group. The L, a, and b values of the dough were highest for the group with 0% perilla leaf powder. Hardness and cohesiveness were lowest for the 0% group and springiness tended to decrease with increased amounts of hot air-dried perilla leaf. The number of microorganisms decreased significantly with greater perilla leaf content on the third and fourth days. As a result of the sensory test, the 6% dough showed the highest scores for all items including appearance, flavor, color, taste, and texture. Overall acceptability was also highest at 7.20 for the 6% dough and lowest at 3.27 for the 12% dough. Based on the above results, when producing fresh noodles by adding hot-air-dried perilla leaf powder, inhibition of microorganisms improved with greater perilla leaf content for longer storage, but the sensory properties were best when 6% perilla leaf content was added.

• 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.

• 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.