• Korean Journal of Food Science and Technology
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• v.7 no.2
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• pp.69-73
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• 1975

Hot air drying of red pepper was studied on the quality of dried products at various drying conditions. In order to investigate the effects of drying methods on the red pepper quality, color appearance, capsanthin (red pigment) and capsaicine (hot taste principle) were analyzed. Color appearance and red pigments of dried red pepper powder were excellently superior to the conventional sun dried products, in spite of partial decolorization by cut drying, at moderate drying temperature ranges from $55^{\circ}C$ to $65^{\circ}C$. A better capsaicine content was recorded at hot air whole dried peppers than the conventional sun dried products. on the other hand about 20 percent loss was observed in cut dried ones. And hot air dried red pepper powder showed better preservative properties than sun dried pepper.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.3
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• pp.192-197
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• 2000

To develop plain dried products of large anchovy, Engraulis japonica, lipid oxidation during drying of large anchovy and optimal drying condition were investigated. The moisture contents of large anchovy on 7 hrs dryness were $ 9.0{\%},\;34.0{\%},\;38.0{\%} and\;38.8{\%}\;in\;60^{\circ}C$ hot-air drying (wind velocity, 1.4m/sec), $40^{\circ}C$ hot-air drying (wind velocity, 1.4 m/sec), sun drying($30{\pm}5^{\circ}C$) and $20^{\circ}C$ cold-air drying (wind velocity, 3.1 m/sec), respectively. The cold-air drying depressed remarkably the lipid oxidation of large anchovy during drying, resulting from AV, POV, COV and the formation of browning pigment. The fatty acid composition of large anchovy was $35.8{\%} in saturates, 20.0{\%} in monoenes and 44.2{\%}$ in polyenes. Saturates and monoenes were increased in proportion to the increase of drying time, while polyenes were decreased. The contents of 20 : 5 and 22 : 6 of polyenes were decreased remarkably in proportion to the progress of lipid oxidation, while 14 : 0, 16 : 0, 16 : 1 and 18 : 1 of saturates and monoenes were increased. The changes in fatty acid compositions by drying conditions were remarkably clarified in sun drying, followed by $60^{\circ}C$ hot-air drying $40^{\circ}C$ hot-air drying and $20^{\circ}C$ cold-air drying in order.

• Journal of Nutrition and Health
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• v.8 no.4
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• pp.33-37
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• 1975

This investigation was designed to determine the influence of drying methods on the free amino acids and free sugars in red pepper and to study the browning mechanism of brown-colored red pepper. Three different drying methods were employed: 1) Sun-drying at $25{\sim}28^{\circ}C$ for 15 days, 2) Drying in oven at $60^{\circ}C$ for 49 hours, and 3) Drying in oven at $90^{\circ}C$ for 8 hours. Dried and ground peels were used for the analysis of free amino acids and free sugars. The results were as follows; 1. Sixteen kinds of amino acids i.e. asparagine, methionine, and cystine etc. were identified. Total amino acid content of the sun-dried sample was not different from that of the fresh sample, but the samples dried at $60^{\circ}C$ and $90^{\circ}C$ in the oven were decreased to 24.9% and 67.4% respectively. Of amino acids identified, methionine, lysine and aspartic acid were decreased in all treatments. Especially, methionine ana aspartic acid were decreased rapidly to 71.8% and 73.3% , respectively. 2. Three kinds of free sugars i.e. glucose, fructose and sucrose were identified. The total content of free sugars was significantly decreased in each treatment. Among the reducing sugars, glucose was rapidly decreased; 65.9% for the glucose of sample dried at $90^{\circ}C$ in the oven. 3. At the higher drying temperature, the darker red color was found. Brown-color appeared at $90^{\circ}C-drying$ showed appreciable losses in carotenoid content, but the major color seems to be due to the large increase in browning compounds. 4. It was assumed that increased browning compounds of red pepper were due to the Maillard reaction which is a nonenzymatic browning process.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.6
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• pp.594-599
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• 2012

The objective of this study was to determine the processing conditions for salt dried rockfish Sebastes schlegeli by sun drying and cold-air drying, as measured by alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase (ALDH) activity. We processed salt dried rockfish samples. The salinity of rockfish samples was within 1% following salting with 25% salt brine for 3 h. The moisture content of salt dried rockfish was found to reduce linearly from 70.12 to 39.5 g/100 g over the same time interval. The water activities of salt dried rockfish by sun and cold-air drying were 0.94 and 0.87, respectively, after three days of drying. Acid values (AV) were 10.71 and 5.96 mg KOH/g, respectively, after the three day drying period. The ADH activity in a water extract from salt dried rockfish following sun and cold-air drying for 24 h was 228.5% and 226.1% at 13.3 mg/mL, respectively, and was higher than that when drying lasted for 48 and 72 h. The ALDH activity was not affected but both ADH and ALDH activity tended to decrease as the drying time increased from 24 to 72 h. The conditions of processing for the best quality of salt dried rockfish were determined to be drying with a cold-air system for 24 h. These results indicated that water extracts from salt dried rockfish have valuable biological attributes owing to the metabolizing of alcohol and can provide useful information for the design of drying systems for salt dried rockfish.

• Journal of the Korean Applied Science and Technology
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• v.33 no.1
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• pp.58-66
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• 2016

This study was performed to investigate drying characteristics and quality properties of dried persimmon with vacuum drying process. Drying characteristic curve of the dried persimmon showed that the constant rate drying period and falling rate drying period exist definitely. $_{\circ}Brix$, sugar content and hardness value of the dried persimmon increased as the vacuum pressure and heating temperature increased, but L value of the dried persimmon lower. The results indicated that the optimal conditions were at vacuum pressure of 40~50kPa abs., heating temperature of $30^{\circ}C$ and drying time of 3~4days.

• Journal of the Korean Society of Food Science and Nutrition
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• v.14 no.4
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• pp.339-344
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• 1985

This study was attempted to check the change of free amino acids in the extractives from ark shell, Anadara broughtonii, during sun-drying. The content of moisture, crude protein and crude lipids of ark shell flesh were 84.7%, 9.6% and 0.8%, respectively. The amounts of extractive-nitrogen from ark shell flesh during sun-drying were 21.18 mg/g in the raw sample, and decreased to 16.25 mg/g after one day sun-drying, and then gradually increased to 31.9 mg/g at the 20th day. The amounts of free amino acid-nitrogen from ark shell flesh during sun-drying were 16.10 mg/g in the raw sample, and decreased to 11.5 mg/g after one day sun-drying and then gradually increased to 17.61 mg/g at the 20th day. In free amino acid composition of raw sample, the most abundent amino acids were glutamic acid (14.1%), histidine (13.8%), arginine(13.7%) and proline (12.1%) in order and taurine was also detected in trace amounts. The amounts of total free amino acids in the extractive from ark shell flesh during sun-drying were 2041.2mg% in the raw sample, and decreased to 1784.0 mg% after one day sun-drying, and then gradually increased to 5277.0 mg% at the 20th day. During sun-drying of ark shell flesh, leucine, isoleucine, valine showed up a increasing tendency, while the amounts of aspartic acid, proline and taurine were decreased.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.8
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• pp.1242-1248
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• 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
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• v.1 no.1
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• pp.17-24
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• 1972

In this paper, the degradation of nucleotides and their related compounds in conger eel muscle during sun drying was studied. The results showed that IMP was dominant in fresh conger eel, showing 75.5% of total nucleotides while the contents of ATP, ADP, AMP, inosine and hypoxanthine were low. The nucleotides tended to degrade rapidly during drying, only 6.2% of IMP remained after seven day's sun drying and ATP, ADP and AMP were also entirely disappeared. In consideration of flavor quality, it was consumed that sun drying is not an effective processing method of conger eel, as far as IMP is concerned.

• Journal of the Korean Society of Food Culture
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• v.35 no.1
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• pp.28-54
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• 2020

This study aims to investigate the food preservation methods adopted by the Joseon Dynasty, which existed before the 17^th century. A total of 232 food preservation methods were discovered in 25 books, and could be classified by their targeted food types: vegetables (84), sea foods (60), meats (41), fruits (37), and others (10). Depending on the preservation method applied, they are classified as food drying, soaking, mud cellar preservation, and other preservation. Food drying is further classified into 8 sub-types: drying, sun-drying, shadow-drying, wind-drying, dry heat, combined drying, smoking, and others. Soaking could be sub-divided into using salt, ash, dry sand, bran, fermented paste, wet distillers grains, oil, and others. Mud cellar preservation is sub-classified into installing shelf inside the mud cellar, making the mud cellar for food preservation, and making hole or underground tunnel for food preservation. Other food preservation methods include minimizing moisture loss by applying beeswax on a section of the vegetable stem, and cutting the vegetables or fruits with their branches and leaves for food preservation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.6023-6028
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• 2013

Recently, biodegradable polymers are gaining more and more attention due to international environmental issues. Succinic acid is synthesised by chemical process of hydrogenation. Succinic acid synthesized has certain amount water content. To remove the water contained in succinic acid is used generally by hot air drying process. But recently, microwave drying process having the advantage of shortening the drying time and uniform drying of product are gaining more attention. In this study, hot air drying and microwave drying efficiency were compared at drying process. In addition, we confirmed commercial applicability in microwave drying process of succinic acid. Microwave drying process has higher efficiency than 70% compared with hot air drying process at thickness of 1cm. Economic efficiency were compared through examination of power consumption for complete drying of succinic acid at microwave and hot air dyring.