• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.12
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• pp.1801-1807
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• 2014

Blue mussels (Mytilus edulis) are widely distributed among the world's oceans in various habitats. The purpose of this study was to investigate the effects of freeze-drying on the antioxidant and antigenotoxic activities of blue mussels collected in the Gyeongnam coast area of Korea. Raw (RM) and freeze-dried blue mussel flesh (FRM) were extracted with ethanol, methanol, and water. Antioxidant activities were evaluated on the basis of DPPH radical scavenging activity, oxygen radical absorbance capacity (ORAC), cellular antioxidant capacity (CAC), and antigenotoxic activity (comet assay). Except for the water extract, RM and FRM showed DPPH radical scavenging activities, which increased upon freeze-drying in MeOH extract. The highest ORAC value was observed in water extract of RM and MeOH extract of FRM. CAC was protected against AAPH-induced oxidative stress in HepG2 cells by both RM and FRM extracts. Freeze-drying lowered ORAC value of water extract, whereas it increased CAC activity, suggesting that antioxidant activities varied according to the generated radicals. All extracts from RM and FRM showed antigenotoxic activities by reducing $H_2O_2$-induced DNA damage in human leukocytes. Freeze-drying had no effect on antigenotoxicity of blue mussels. Taken together, these results indicate that blue mussels possess antioxidant and antigenotoxic properties, and freeze-drying might be a useful processing method for blue mussels to retain their maximum physiological potential as a functional food.

• Food Science and Preservation
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• v.24 no.2
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• pp.246-253
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• 2017

This study was conducted prepare spray-dried powder using pumpkin sweet potato hydrolysates and examine the physicochemical properties of the powder. The insoluble dietary fiber and soluble dietary fiber of the pumpkin sweet potato treated by enzyme were 4.17% and 2.07%, respectively. The spray-dried pumpkin sweet potato hydrolysates was manufactured via spray-drying with different forming agents: i.e., pectin 0.1%, 0.5%, 1%, and 2.0%. The moisture contents and total starches of the spray-dried powders were approximately 1.68-2.46 and 45.32-46.51%, respectively. The color of the L and a value decreased, and that of the b and ${\Delta}E$ value increased. The particle size and outer topology of the spray-dried powders were $37.17-42.32{\mu}m$, and its shape was generally globular. The water absorption index of the spray-dried powder (1.74-1.91) was lower than that of the freeze-dried powder (2.15). The water solubility index of the spray-dried powder, 80.75-87.61%, was higher than that of the freeze-dried powder (70.47%). The adhesion values of spray-dried powder to epithelial HT-29 cells were 2.66-6.18% of the initial cell counts, whereas freeze-dried powder showed lower adhesive ability (1.79%). The in vitro human digestibility in the spray-dried powder was 70.09% which is very effective in digestion.

• Journal of the Korean Applied Science and Technology
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• v.35 no.4
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• pp.1320-1326
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• 2018

This study investigated the antioxidant and neuronal cell protective effects of activity of water and 70% ethanol extracts from Stachys sieboldii Miq. according to different drying method(hot air drying and freeze-drying). The total flavonoid and total polyphenol content in water extracts was significantly higher after freeze-drying compared to hot air drying(p<0.05). DPPH and ABTS radical scavenging were increased in a dose-dependent manner. The DPPH and ABTS radical scavenging activity of water extract were significantly higher after free-drying compared to hot air drying(p<0.05). In a cell viability using MTT, the water extract according to hot air drying and freeze-drying of Stachys sieboldii Miq. showed protective effect against H2O2-induced nurotoxicity. The results suggest that the water extracts of Stachys sieboldii Miq. after freeze-drying has antioxidant activities and may be useful for neurodegenerative disorders.

• Korean Journal of Food Science and Technology
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• v.38 no.4
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• pp.513-520
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• 2006

Spray-dried (SD) and freeze-dried (FD) takju powders were stored at 5, 15 and $25^{\circ}C$, and various quality characteristics such as moisture, amino nitrogen, color value, total viable cell count, total sugar, reducing sugar organic acid, and flavor compounds were measured for 50 days at 10-day intervals. After 50 days of storage, the moisture content was increased from an initial 6.64% to 7.24-7.38% in the SD powder, and from an initial 4.86 to 5.43-5.61% in the FD powder. pH, total acid content and total viable cell counts were slightly increased. Organic acid content was decreased in the SD powder from an initial 3,949.9 mg% to 805.9-922.3 mg%, and in the FD powder from an initial 5,171.5 mg% to 3,646.0-4,110.2 mg%. Amino nitrogen content was increased in the SD powder from an initial 1.2% to 1.9-2.2% and in the FD powder from an initial 1.9% to 2.2-2.5%. Total sugar and reducing sugar contents were increased in the SD powder from an initial 17.2% and 4.0% to 25.9-27.3% and 5.8-6.9%, and in the FD powder from an initial 19.1% and 5.2% to 29.2-30.2% and 8.3-8.8%, respectively. With increasing storage time, L and b values in the SD powder increased slowly, while L value in the FD powder tended to decrease and b value tended to increase. About 20 major volatile flavor components were identified in the SD and FD powders by GC-MS and all such component levels were decreased with increasing storage time.

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

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.7
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• pp.909-913
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• 2009

This study was conducted to investigate the rehydration properties and the sensory quality of sun-dried (SD), hot-air dried (HD), and freeze-dried (FD) cooked rice as space food. Rehydration ratio of HD and FD were significantly higher than those of SD, but there was no significant difference between HD and FD (p<0.05). A cross section of SD showed the smooth surface without any cavities. While HD showed large cavities, many small air cells in FD were observed by a scanning electronic microscope. Stickiness/hardness ratio of HD was similar to that of FD and significantly higher than SD (p<0.05). Also, sensory properties of HD and FD were significantly higher than those of SD, but there were no differences between HD and FD (p<0.05).

• Korean Journal of Food Science and Technology
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• v.31 no.1
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• pp.128-137
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• 1999

In this study, shiitake mushrooms were dried by hot air, vacuum and freeze drying methods and theire physical properties were compared. Since the pore size affects the amount of absorption, the characteristics of water sorption were investigated at various humidities and temperatures. Results showed that the freeze dried product had the greatest pore area and the highest absorption capacity. However, all the dried samples showed similar quality. The browning degrees were severely changed with increased relative humidities and temperatures. Among these drying methods, the freeze drying gave the greatest change in browning degree. The GAB monolayer moisture contents of the dried shiitake mushroom were $5.3{\sim}7.7%$. The prediction model was also provided using parameters such as relative humidity, temperature and pore area.

• Korean Journal of Food Science and Technology
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• v.38 no.2
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• pp.188-196
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• 2006

Changes in physicochemical characteristics and functional components content of saengsik, uncooked food, were investigated to find efficient drying methods, one of important manufacturing process of saengsik. No changes in proximate compositions of all samples were observed during hot-air drying at 50, 55, and $60^{\circ}C$ and freeze-drying. Colors of carrot, Lentinus edodes, and sea mustard did not change, while a value of cabbage, L, a, and b values of Agaricus bisporos, and a value of laver changed slightly by hot-air drying at all temperatures and freeze-drying. Dietary fiber content increased by hot-air drying but not by freeze-drying. Reductions in vitamin C and ${\beta}-carotene$ contents of carrot, cabbage, sea mustard, and laver were higher by hot-air drying than by freeze-drying. Contents of total phenolics and lectin of L. edodes and A. bisporos were not affected by hot-air drying and freeze-drying. Contents of pectin, alginic acid, and porphyran in sea mustard and laver increased by hot-air drying.

• Korean Journal of Plant Resources
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• v.35 no.4
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• pp.455-463
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• 2022

The effects of freeze-drying (FD), room-temperature drying (RD), and room-temperature drying after roasting (RDAR) on the volatile organic compounds (VOCs), sugar content, flavonoids, and antioxidant activity of Hallabong peel tea were tested. This experiment was conducted to collect a basic information for developing of peel tea. FD samples showed lower total soluble solids and VOCs than other drying treatments. RDAR samples showed a significant difference in VOCs and visual color of FD samples. The reduced VOCs in FD samples was caused by freeze drying treatment; identical VOCs composition of hallabong peel was detected from condensed ice of freeze-drying machine. Metabolomics analysis showed no difference among three drying treatments. In addition, antioxidant activity and total phenolic compounds were not significantly different from three different drying treatments. Thus, RD or RDAR is a suitable drying method for hallabong peel tea rather than FD method in terms of VOCs and economical reasons.

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