• Journal of Ginseng Research
• /
• v.32 no.2
• /
• pp.155-160
• /
• 2008

The North American ginseng (Panax quinquefolius L.) seed crop varies from year to year. The ability to hold stratified seed for a year would ensure continuity of seed supply and no interruption in production cycles. Seed drying and rehydration protocols at room temperature $(21{\pm}2^{\circ}C)$ were developed. These protocols and seed storage at 4 ${\pm}1^{\circ}C$ and 35%, or variable, relative humidity (RH) allowed the holding of stratified seed for one year and then establishment of the following five treatments in field plots: Trt.1 : dried 2005 stratified seed (seed harvested Fall 2004) held at $4^{\circ}C$ and at variable humidity; Trt.2 : 2006 stratified seed planted directly into the field; Trt.3 : 2005 stratified seed dried in October 2005 and held at $4^{\circ}C$ and 35% RH ; Trt.4 : 2005 stratified seed held in moist sand from October to December 2005 at room temperature $(21{\pm}2^{\circ}C)$ and then in December dried and held at $4^{\circ}C$ and 35 % RH; Trt.5 : 2005 stratified seed held in moist sand from October to December 2005 at room temperature and then in December dried and held at $-12^{\circ}C$ Seedling emergence was best in Trts. 2 and 4 with 67.3 and 65.1% respectively which is similar to the industry expected rate of 68% after regular stratification. Seedling growth was similar in Trts. 2 and 4 with root dry weights of 172 and 159 mg respectively in mid-August. Therefore, if holding stratified seed in August/September for one year is desired, the seed can be placed in moist sand until December and then dried and stored at $4^{\circ}C$ and 35% RH. These seed can be planted in the following August/September and will germinate and grow in the following year to give an acceptable crop.

• Korean Journal of Food Science and Technology
• /
• v.28 no.1
• /
• pp.72-76
• /
• 1996

Hot air drying of Lentinus edodes was studied using the microcomputer drying system that can control the drying parameters such as air temperature, relative humidity and a weight-loss of water. The physico-chemical properties of dried products were measured in order to investigate the drying characteristics. The mechanism of water movement during air drying of Lentinus edodes closely followed the Page model. That was $M-M_c/M_0-M_c\;=\;\exp\;(-0.275t^{1.154})$ at $50^{\circ}C$ and 20% RH. The free amino acids increased with increased relative humidity. The color and browning degree increased with increased air temperature and relative humidity. The rehydration rate was low when the air temperature and relative humidity were high.

• Food Science and Preservation
• /
• v.23 no.6
• /
• pp.819-824
• /
• 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 Food Science and Technology
• /
• v.35 no.3
• /
• pp.393-398
• /
• 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.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.12 no.3
• /
• pp.230-235
• /
• 1983

Physicochemical properties of instant rice prepared by hot-air drying, alcohol dehydration and freeze-hot air drying were studied. Freeze-hot air drying rice showed the fastest rehydration rate as well as the most desirable textural characteristics. Sensory evaluation suggested that the freeze-hot air drying rice also had more desirable taste, flavor and texture. However, color was more desirable in alcohol dehydrated rice.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.35 no.1
• /
• pp.104-108
• /
• 2006

Effect of gamma irradiation on the softening of dried fernbrake at different moist-heating conditions was investigated. Dried fernbrake packaged in controlled atmosphere $(CO_2\;25\%,\;N_2\;75\%)$ was irradiated up to 7 kGy with $\gamma-ray$. Hardness of dried fernbrake was significantly decreased at the irradiation dose of above 5 kGy. Hardness of cooked fernbrake was significantly decreased with increasing irradiation dose level as well as heating temperature and time. $DT_{50}$ value (The heating time required to reach the $50\%$ reduction of hardness) for irradiated fernbrake was shortened according to dose level as well as heating temperature and heating time: $DT_{50}$ value of control: 23 min, 5 or 7 kGy: $2.2\~5.0$ min at $60^{\circ}C$. Also, the activation energy for softening of irradiated fernbrake ($1.85\~1.88$ kcal/mole for $5\~7kGy$) decreased compared to control (4.30 kcal/mole). Moisture content, swelling and rehydration rate of gamma irradiated fernbrake during moist heating increased according to the irradiation doses. Sensory results showed that scores of off-flavor and odor in irradiated fernbrake upto 7 kGy were not significantly different from control. Based on these results, gamma irradiation was effective for the reduction of cooking time and the activation energy for softening of dried fernbrake with increasing dose levels.

• Korean Journal of Food Science and Technology
• /
• v.40 no.2
• /
• pp.178-183
• /
• 2008

This study investigated the effects of osmotic dehydration (OD) and vacuum impregnation (VI) on the quality of dried apple products. Weight reduction and water loss increased during OD, but these decreased in the apples during VI. In particular, VI's effect on increasing solid gain was superb. For apples in 40% sucrose solution, OD and VI were followed by hot-air drying at 50$^{\circ}C$. The experimental data were fitted successfully using the modified Page model. OD and VI increased drying time and decreased the drying rate constant of these apples as compared to the control. Shrinkage and rehydration capacity greatly decreased in the apples dried by OD and increased in the apples dried by VI as compared to the control. OD also decreased titratable acidity and ascorbic acid content considerably. Sensory evaluations of the products indicated that the apples prepared by OD had higher palatability in their rehydrated form in yoghurt, and the apple products prepared by VI had higher palatability in their dried form.

• Journal of Applied Biological Chemistry
• /
• v.62 no.3
• /
• pp.251-255
• /
• 2019

The effect of soaking temperature on the moisture uptake and the protein loss of soybeans during soaking process investigated. As the soaking temperature increased, the soaking rate significantly increased and Peleg model was suitable for describing the soaking characteristics of the soybean with high $R^2$ values (>0.991). The soaking time to achieve the target moisture content of soybean (130%) was estimated to be 12.6, 3.11 and 2.31 h at 25, 35 and $45^{\circ}C$, respectively. Peleg model well described the protein loss kinetics of soybean during soaking with high $R^2$ values (>0.941). The results showed that the protein loss of soybean at the target moisture content were 35.2, 93.1 and 103.0 mg/g at 25, 35 and $45^{\circ}C$, respectively. In this study, the optimum soaking condition for quality of soybean was 12.6 h of soaking time at $25^{\circ}C$.