• Korean Journal of Food Science and Technology
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• v.50 no.3
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• pp.339-343
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• 2018

Effects of different drying processes, such as hot air drying (HA), superheated steam with hot air drying (SHS/HA), and superheated steam with far infrared radiation (SHS/FIR), on the properties of cherry tomatoes (Solanum lycopersicum var. cerasiforme) were studied. Characteristics of dried cherry tomatoes were determined by examining the water content, internal microstructure, and rehydration capacity under different drying processes. Moreover, ascorbic acid (AA) and lycopene levels were also measured to evaluate thermal damage caused by drying. Cherry tomatoes dried using both SHS/HA and SHS/FIR had water content and water activity similar to those of intermediate moisture food, indicating partial dehydration after combined drying processes. Although AA and lycopene levels decreased drastically after drying, tomatoes dried using SHS/FIR showed the lowest losses of AA and lycopene among samples. Cherry tomatoes dried using SHS/FIR showed a less compact internal cell structure than that of cherry tomatoes dried using HA and SHS/HA, resulting in the highest rehydration capacity. These results suggest that a combined drying process such as SHS/FIR is more effective than conventional hot air drying for the production of partially dried cherry tomatoes with improved quality attributes.

• Food Engineering Progress
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• v.22 no.4
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• pp.315-320
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• 2018

This study examined the effects of drying methods of Aronia melanocarpa on contents of total polyphenols and flavonoids, antioxidant activity and anti-inflammatory activity. As a result, freeze-dried aronia extract (FDAE) significantly exhibited higher contents of total polyphenols and flavonoids (155.76 mg GAE/g and 105.70 mg QE/g) than hot-air dried aronia extract (HDAE) (134.93 mg GAE/g and 82.29 mg QE/g). Also, FDAE showed greater antioxidant activity than HDAE in both DPPH and ABTS. For anti-inflammatory activity, NO production from lipopolysaccharide activated RAW264.7 cell reduced at a dose-dependent manner in both FDAE and HDAE. However, reduction rate of NO production is higher in FDAE (62.7%) than in HDAE (33.5%). These results suggest that comparatively, freeze-drying is a better method for preserving the antioxidant and anti-inflammatory activities and of aronia.

• Food Science and Preservation
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• v.23 no.1
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• pp.57-62
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• 2016

The present study was undertaken to determine the changes of physicochemical and antioxidant activity using leaf and root in hot air-dried Allium hookeri (HA) and freeze-dried Allium hookeri (FA). The leaf of HA was higher level of moisture and crude fat compared with those of the leaf of FA. The crude fat content in root of HA was higher than that in FA. However, moisture, crude ash, crude protein and carbohydrate did not show any differences between two different drying methods. The organic acid contents of Allium hookeri root including oxalic acid, citric acid, tartaric acid, malic acid, succinic acid, lactic acid, formic acid, acetic acid showed the differences between hot air-drying and freeze-drying methods. The major minerals were Ca, K and Mg, which were higher level of the leaf of HA compared with those of FA. The leaf of HA showed the highest vitamin C content (801.65 mg/100 g). The content of vitamin E in the leaf of FA was higher than that of HA. The contents of total polyphenol and total flavonoid in the FA leaf were higher than that in HA. The DPPH radical-scavenging activity in leaf of HA (65.73%) was significantly higher than that of FA (57.73%).

• Korean Journal of Food Science and Technology
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• v.33 no.2
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• pp.245-251
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• 2001

This research was conducted to study the changes in physical characteristics of mushrooms (Agaricus bisporus) as influenced by drying methods. Samples were dried using either hot air drying, vacuum drying, or freeze drying and changes in the color, browning index, hardness and rehydration rate were evaluated by response surface methodology. Hot air drying resulted in the fastest drying of sample as compared to other methods. The rate of drying was most affected by the environmental temperature rather than air velocity or vacuum pressure. The overall color difference increased as the temperature and air velocity increased. The overall color changes of the freeze dried samples were minimal as compared to those of fresh mushrooms. The hot air dried samples showed the greatest changes in the overall color, browning index as well as hardness. The freeze dried samples showed the best rehydration characteristic and maintained the best overall quality after drying.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.3
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• pp.342-347
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• 2007

Physicochemical properties of onion powder as influenced by drying methods were investigated. Moisture contents of onion powder were 13.29%, 12.99%, and 10.78% for samples dried using hot-air dryer, freeze dryer, and vacuum dryer, respectively. There were no significant differences in crude fat, crude protein, and crude ash content (p>0.05) depending on the drying methods. Samples prepared by freeze drying showed a significantly higher L-value as compared with those prepared by hot-air and vacuum drying (p<0.05). Scanning electron micrographs showed that freeze drying produced smaller particle-sized sample which in turn resulted in the higher porosity of the sample. Freeze dried samples revealed significantly lower degree of rehydration than other samples (p<0.05) probably due to small particle size of the sample. Water solubility of freeze dried sample appeared to be higher than that of other drying methods while the swelling ratio of the same sample appeared to be lower than that of the others. Browning index was significantly lower in samples prepared by freeze drying (p<0.05) but not significantly different between samples dried by hot-air and vacuum drying. Vitamin C content was higher in freeze dried onion powder due to the lower temperature applied to the sample. Freeze dried onion powder contained significantly lower amount of total polyphenol and higher amount of total sugar as compared to other samples (p<0.05).

• Korean Journal of Medicinal Crop Science
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• v.14 no.1
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• pp.8-13
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• 2006

This study was carried out to investigate drying methods for keeping freshness and active components of aerial part of Saururus chinensis. Chopped samples were prepared using hot air drying, hot air drying + roasting, presteamed + hot air drying, freeze drying, and sun drying. Drying time was shorter $88{\sim}93%$ in hot air drying and freeze drying than in sun drying. Percentage of dry matter was higher in the order of freeze drying > sun drying > hot air drying, and moisture content in the order of sun drying > hot air drying > freeze drying. The contents of total phenolics and quercetin related substances were greater in the order of freeze drying > hot air drying > sun drying, while were decreased due to treatments before or after hot air drying. Electron donating ability (EDA) was highest in freeze drying, and showed a little difference between hot air drying and sun drying, but was increased because of treatments before or after hot air drying. In color values, the a value was lower in the order of freeze drying < hot air drying < sun drying. The contents of active components of plant parts of hot air dried were higher in the order of flower >leaf > chopped sample > stem. EDA showed similar tendency with those. The a value was lower in the order of leaf < chopped sample < flower < stem. As a result, freeze drying of chopped samples or hot air drying of leaf and flower were effective to maintain qualities of aerial part of Saururus chinensis.

• Food Science and Preservation
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• v.7 no.4
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• pp.389-394
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• 2000

To utilize deteriorated sweet persimmon(Diospyros kaki T.) effectively, this study was investigated about the effective (Dying method of the powder. Chemical components, minerals, fatty acids and amino acids of hot-air dried and freeze dried conditions were determined Sample conditions used on analysis as follow; pretreatments of hot-air dry and freeze dry were soft, soft+peel, mixer, mixer+peel. The contents of crude protein, crude lipid, crude ash of hot-air dry were 0.9-1.1%,15.0-39.0% and 2.3-3.3%, respectively. And those of freeze dry were 1.3-2.2%, 27.-49.0% and 2.5%, respectively. Potassium, magnesium, phosphorus, calcium and sodium content in hot-air dry and freeze dry were high. Other minerals were less than 3.00ppm in all conditions. The major fatty acid contents were detected capric acid(C$\^$10:0/), lauric acid(C$\_$l2:0)/, tridecanoic acid(C$\_$13:00/), palmitic acid(C$\_$l6:00/), palmitoleic acid(C$\_$l6:1/), oleic acid(C$\_$18:1), linoleic acid(C$\_$18:2/), linolenic acid(C$\_$18:3/). The essential amino acids such as aspartic acid, threonine, serine, glutamic acid, glycine, alanine, valine, methirmine, isoleucine, leucine, tryosine, phenylalanine, histidine, lysine, arginine in freeze dry were contained richly. On the basis of chemical analysis, hot-air dry method will have to supply the additional different method, because simple hot-air dry method was shorten the dry time but had many problems. Therefore, the effective drying method considering changed color and nutrition was shown freeze dry method.

• Journal of Life Science
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• v.31 no.7
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• pp.617-625
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• 2021

To enhance the applications of apple pomace, which is a by-product of apple, this study analyzed the nutritional components, ursolic acid content, and antioxidant activity of different solvent (distilled water, fermented alcohol, and methanol) extracts. The samples included hot air-dried and freeze-dried apple pomace. The moisture, protein, fat, ash, and total dietary fiber contents of hot air-dried apple pomace were 3.2%, 3.9%, 2.4%, 2.0%, and 28.5%, respectively, and those of freeze-dried apple pomace were 8.2%, 3.4%, 2.4%, 1.8%, and 33.0%, respectively. Ursolic acid was not detected in the distilled water extract of either sample. However, in hot air-dried apple pomace, the methanol extract was 1,753.32 ㎍/ml, and the fermented alcohol extract was 1,532.94 ㎍/ml. In freeze-dried apple pomace, the methanol extract was 1,407.04 ㎍/ml, and the fermented alcohol extract was 1,221.81 ㎍/ml. The total polyphenol and flavonoid contents were 306.7 ㎍/ml and 950.1 ㎍/ml, respectively in methanol extracts of hot air-dried apple pomace and 277.6 ㎍/ml and 925.0 ㎍/ml, respectively in methanol extracts of freeze-dried apple pomace. 2, 2'-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities of hot air-dried apple pomace were 73.3% in methanol extract and 59.4% in fermented alcohol extract, and those of freeze-dried apple pomace were 76.1% in methanol extract and 66.0% in fermented alcohol extract. Both samples had the lowest antioxidant activity in distilled water extracts. Similar to DPPH radical scavenging activity, both samples showed increasing 2,2'-azino-bis(3-ethylbenzothiazoline-6- sulfonic acid) (ABTS) radical scavenging activity in the order of methanol, fermented alcohol, and distilled water. All samples had stronger reducing power than ascorbic acid (311.5 ㎍/ ml) as a positive control.

• Journal of the Korean Society of Food Culture
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• v.20 no.6
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• pp.738-743
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• 2005

This study was performed to investigate the quality characteristics of pine mushroom yanggaeng prepared with different additions and different preparations of pine mushroom. Yanggaeng was prepared with three concentration of pine mushroom after different preparations of pine mushroom, A hot wind drying 0.1%, 0.3%, 0.5%, Frozen pine mushroom grinding 0.1%, 0.3%, 0.5%, Freezed drying 0.1%, 0.3%, 0.5%, to which was added cooked red bean, agar, oligosaccharide, salt and water. Proximate composition, hunter's color, texture profile analysis and sensory evaluation of yanggaeng were examined. Lightness of pine mushroom yangaeng increased with increasing pine mushroom content and frozen pine mushroom grinding products were higher than those of the preparation products. In the texture profile analysis, hardness of pine mushroom yangaeng increased with increasing pine mushroom content and cohesiveness, springiness of Frozen pine mushroom grinding 0.1% were the highest. In sensory evaluation, the taste and viscosity scores of Freezed drying 0.1% higher than those of the other products. Also the overall acceptability of freezed drying 0.1% pine mushroom yanggaeng was the highest of the all products.

• Korean Journal of Food Science and Technology
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• v.34 no.5
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• pp.805-810
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• 2002

Development of tenderizer using domestic fruits was studied. Kiwifruit was dried using various methods, and the quality of kiwifruit powder was observed during 12 week storage. Frozen kiwifruit was prepared in paste, dice, and whole flesh. After drying, paste-type kiwifruit showed 2.0 and 1.3 times higher proteolytic activity than dice and whole flesh kiwifruits, respectively. Nine hour of hot-air drying or 46 h of freeze-drying eliminated more than 90% of water from kiwifruit, during which discoloring of kiwifruit occurred. Freeze-dried powder showed 6.6 times higher yield and proteolytic activity, and resulted in almost no discolorization than those of air-dried powder. Addition of bulking agent affected the quality of hot air-dried kiwifruit powder, except color, resulting in $3.2{\sim}3.6$ times higher proteolytic activity than that without bulking agent, which is comparable to 60% of the initial freeze-dried powder content. Moisture content of kiwifruit powder with bulking agent sustained consistently during 12 week storage, whereas proteolytic activity decreased for the first 4 weeks. Freeze-drying is a preferable method to produce kiwifruit powder for tenderizer, although hot air-drying with bulking agent treatment is more economical.