• Applied Biological Chemistry
• /
• v.32 no.3
• /
• pp.286-294
• /
• 1989

Effects of cooking and drying methods on the quality of shrimp, Metapenaeus joyneri, were investigated. The cholesterol content of fresh shrimp was 81.4mg/100g of dry basis. It was $5{\sim}28%$ less in freeze dried shrimps as compared to hot air dried shrimps. The volatile basic nitrogen and trimethylamine contents of hot air dried shrimp was higher than those of freeze dried one, but total viable count of freeze dried shrimp was lower than that of hot air dried one. The color of cooked-shrimps was much brighter than uncooked-fresh shrimp. Freeze dried shrimp was lighter than hot air dried one. Total color difference $({\Delta}E)$, however, was opposite to its lightness. The mineral component of fresh shrimp was composed of calcium predominantly, followed by potassium and sodium, which were 96% of the total mineral contents. Cooking and drying methods did not affect the mineral content.

• Korean Journal of Food Science and Technology
• /
• v.30 no.4
• /
• pp.877-882
• /
• 1998

To establish optimum drying methods for Korean yam, freeze drying, cool air drying and hot air drying methods were compared by determining some quality criteria. The native color, odor, taste and viscosity of raw yam were preserved by only freeze drying at less than $40^{\circ}C$. The native white color of yam changed to brown and odor and taste of yam decreased largely by cool air drying and hot air drying. Especially cooked and roasted flavor was developed in hot air dried yam. The viscosity of cool and hot air dried yam was about half than that of freeze dried yam. Conclusively freeze drying method was shown optimum to preserve quality properties of yam such as viscosity, color, odor and taste. The physical properties of yam powder such as dispersiveness and solubility was the best in $40{\sim}60{\;}mesh$ particle size.

• Elastomers and Composites
• /
• v.43 no.1
• /
• pp.1-7
• /
• 2008

Far-infrared vulcanization of ethylene-propylene-diene terpolymer(EPDM) compounds has been studied in comparison with hot air vulcanization. Vulcanization characteristics of EPDM compounds were measured by degree of curing and temperature of specimens in vulcanization process. As a result, degree of curing by far-infrared of EPDM compounds was shown to be higher value than that by hot air at the same vulcanization temperature. Especially, degree of curing by far-infrared on 3 mm thickness of EPDM compounds was increased by two times compared to that by hot air. While the increase of thermal conductivity of EPDM compounds highly improved degree of curing by far-infrared, that hardly improved degree of curing by hot air.

• Korean Journal of Food Science and Technology
• /
• v.34 no.1
• /
• pp.37-42
• /
• 2002

This study was performed to provide basic that will predict the usefulness of Gastrodiae Rhizoma as food materials. The physicochemical properties of raw, freeze-dried, and hot air-dried Gastrodiae Rhizoma were investigated and analyzed. The moisture content of raw Gaxtrodiae Rhizoma was 81.20%. The moisture, crude protein, crude fat, crude ash and carbohydrates of freeze-dried Gastrodiae Rhizoma were 7.61%, 6.21%, 1.50%, 2.55%, and 89.74%, respectively. The total dietary fiber (TDF) of freeze-dried Gastrodiae Rhizoma was 11.68%. The K (1265.03 mg%) was the highest mineral found in Gastrodiae Rhizoma. Aspartic acid (1272.10 mg%) and glutamic acid (1249.50 mg%) in Gastrodiae Rhizoma were major amino acids. Linoleic acid (53.79%), palmitic acid (20.17%), oleic acid (11.93%), and linolenic acid (4.78%) were principal fatty acids in crude fat of Gaxtrodiae Rhizoma. Most of the free sugars of freeze-dried Gastrodiae Rhizoma was maltose (11.04%). In color, the freeze-dried showed the highest lightness (94.52) and the $60^{\circ}C$ hot air-dried showed the highest redness(0.76) and yellowness (16.41). The color differences among freeze-dried, $40^{\circ}C$ hot air-dried, and $60^{\circ}C$ hot air-dried Gastrodiae Rhizoma were distinguished markedly. Vitamin C contents in raw, freeze-dried, and $60^{\circ}C$ hot air-dried Gastrodiae Rhizoma were 0.015%, 0.010%, and 0.002%, respectively. The organoleptic characteristics of raw, freeze-dried, and hot air-dried Gastrodiae Rhizoma were evaluated and compared on the basis, 5 points of raw Gastrodiae Rhizoma by 9 points scale. The undesirable characteristics, such as fishy odor, sewage odor, bitter taste, bad and salty taste, decreased, while desirable characteristic such as sweet taste was maintained or increased considerably as drying temperature got higher.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.43 no.6
• /
• pp.893-900
• /
• 2014

The aim of this study was to investigate physicochemical changes in Salvia plebeia R. Br. (SPA) upon hot-air drying and blanching. After hot-air drying and blanching, total polyphenol and flavonoid contents were reduced from 96.64 mg and 48.40 mg gallic acid equivalent/g to 29.70 mg and 22.10 mg quercetin equivalent/g, respectively. DPPH radical scavenging activities at $25{\mu}g/mL$ of SPA were 94.5% for ascorbic acid, 84.3% for hot-air dried SPA, and 59.7% for blanched SPA and there was no significant difference between those of hot-air dried SPA and ascorbic acid as a positive control. Total sugar contents were 7.187% and 6.104% for hot-air dried SPA and blanched SPA, respectively. During the blanching process, sucrose and maltose contents decreased, whereas glucose and fructose contents increased. Glucose and fructose were converted into citric acid in blanched SPA, whereas sucrose and maltose were converted into tartaric acid, malic acid, and succinic acid. Fourteen kinds of amino acids were found, but methionine, lysine, glycine, histidine, and cysteine were absent. The proportion of essential amino acids was 61.76% upon hot-air drying, which was a relatively high amount. In addition, hot-air drying resulted in 1.40 mg/100 g of norvaline as well as 39.00 mg/100 g of GABA, which are non-amino acids. Therefore, Salvia plebeia R. Br. can be used not only as vegetables but also as highly useful and various health functional foods with antioxidant effects and excellent nutrition.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.42 no.8
• /
• pp.1242-1248
• /
• 2013

This study was performed to determine the effects of pretreatment (NT: non-treatment, BTS: boiling treatment with 3% sodium chloride, DTG: dipping treatment in glycerol) and drying methods (sun drying, hot air drying, and cold air drying) on the physicochemical properties and antioxidant activities of dried jujube (Zizyphus jujuba Mill.) fruits. Our results show that moisture content is lower (P<0.05) with DTG, and that moisture content is lower with hot air drying compared to other drying methods. The bulk density was highest with BTS. The soluble solids content was highest with DTG. Additionally, the soluble solids content were highest in the following order: hot air drying> cold air drying> sun drying. The titratable acidity of hot air drying was highest of all the drying methods. The titratable acidity was higher with NT and DTG, and the brix and acid ratio of sun drying was higher than other drying methods. Among the drying methods, BTS showed the best browning-retarding effect, whereas boiling treatment affected quality and color. The total polyphenol content from hot air drying and NT or DTG treatment was relatively higher than the content from BTS. The flavonoid content was highest with BTS, and all dried jujube showed relatively high antioxidant activities. The sensory evaluation results indicated that the organoleptic scores for overall preference were higher in the NT and DTG treatment groups. These results suggest that pretreatment and drying methods affect the quality of dried jujube fruit, and show that glycerol treatment with hot air drying can be applied to the production of high quality dried jujube.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.41 no.10
• /
• pp.1388-1394
• /
• 2012

The physiological functionalities of 70% ethanol extracts (EE) from Cudrania tricuspidata fruit (ECFD, EE of C. tricuspidata subjected to freeze-drying; ECHD, EE of C. tricuspidata subjected to heat air drying; ECID, EE of C. tricuspidata subjected to infrared drying) were investigated. Yields of freeze-dried powders of ECFD, ECHD, and ECID were 51.50%, 53.91%, and 56.14%, respectively. Color $L^*$, $a^*$, $b^*$, and $H^{\circ}$ values of ECHD and ECID decreased. Dried ECHD and ECID had relatively higher contents of total polyphenolics and flavonoids than ECFD. Electron donating abilities at a concentration of 10 mg/mL (w/v) were in order of ECID (62.37%) >ECHD (80.17%)>ECFD (77.80%). Reducing powers ($OD_{700}$) of ECFD, ECHD, and ECID were 0.75, 1.70, and 1.89, respectively. Additionally, ABTS radical scavenging ability of ECID was the highest with a value of 62.37% at a concentration of 10 mg/mL (w/v). Nitrite scavenging activities of ECFD, ECHD, and ECID at a concentration of 10 mg/mL (w/v) were 28.76%, 30.69%, and 41.64%, respectively. SOD (superoxide dismutase)-like activities at 5 mg/mL (w/v) were in the order ECFD (891.93 mUnits)>ECHD (723.02 mUnits)>EFID (611.97 mUnits). Whereas ferrous ion chelating activity of ECFD (52.36%) and ECID (47.16%) was significantly higher than that of ECHD (30.04%). ACE inhibitory and xanthine oxidase (XO) inhibitory activities of ECHD and ECID at a concentration of 1 mg/mL (w/v) were higher than those of ECFD. In conclusion, we provided experimental evidence that extracts of pre-dried C. tricuspidata exhibit increased physiological functionalities. Further, infrared drying technique is the best method for enhancement of antioxidant activity of C. tricuspidata fruit.

• Korean journal of food and cookery science
• /
• v.18 no.1
• /
• pp.13-19
• /
• 2002

This study was performed to develop natural spices using Cheongung (Cnidium officinale) which is one of the Korean medicinal plants, Cnidium of officinale is a perennial plant of the Umbelliferae family and is widely distributed in Korea. The overall acceptances of flavor and color, and the masking effects on meaty and fishy flavor of Cnidium officinale were investigated by sensory evaluation. The overall acceptances of fresh Cnidium officinale were the highest, followed by freeze dried and hot air dried samples. The meaty and fishy flavor of cooked pork and fish were significantly reduced by the addition of fresh, hot air dried and freeze dried Cnidium officinale. Cnidium officinale showed similar or higher masking effects on meaty and fishy flavor compared with black pepper.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
• /
• v.11 no.4
• /
• pp.22-27
• /
• 2015

Quality characteristics of Shiitake mushroom using two types of dryers, energy-efficient heat pump hot-air dryer and electric heater hot-air dryer were compared. Energy consumed during drying by heat pump hot-air dryer and electric heater hot-air dryer were 22.8 kWh and 28.9 kWh, respectively. Total polyphenol content of heat pump hot-air dryer and electric heater hot-air dryer after drying were $290.55{\pm}10.56ppm$ and $192.99{\pm}6.53ppm$, respectively. No differences were observed between dryers in reconstitution rate and browning ratio after drying. Also, there were no differences between dryers in color value and ${\Delta}E$ value after drying. Shiitake mushroom drying at $45^{\circ}C$ by heat pump hot-air dryer was proved to be more efficient in energy consumption than by electric heater hot-air dryer.

• Korean Journal of Food Science and Technology
• /
• v.22 no.1
• /
• pp.44-49
• /
• 1990

The quality of garlic powder produced by hot all drying and freeze drying method was evaluated Porapak Q column was comparatively profitable for the separation of flavor components in hexane extracts of garlic. Freeze dried (FD) garlic powder had higher diallyl disulphide, total pyruvic acid and alliin than hot air dried (HD) garlic powder. On the results of color evaluation by color difference meter, garlic powder of HD were more brownish than FD. In microstructure of garlic powder observed by SEM, freeze dried garlic powder was fairly porous.