• Korean Journal of Food Science and Technology
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• v.46 no.5
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• pp.636-640
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• 2014

This study was conducted to provide basic information about the drying methods (daylight, hot-air, and freeze drying) used for Platycodon grandiflorum radix. We investigated the mineral, free sugar, and saponin contents of dried P. grandiflorum. The potassium and calcium contents of hot-air-dried samples were the highest (22.6 and 9.2 mg%, respectively), when compared to those of daylight- or freeze-dried samples. Glucose and sucrose contents were the highest in freeze-dried samples (1,552 and 145.0 mg%, respectively), while fructose content was the highest in hot-air-dried samples (611.9 mg%). Platycodin D content was the highest in hot-air-dried samples (622.0 mg%); however platycodin D3, polygalacin D, and deapioplatycodin D contents were the highest in daylight-dried plant (113.5, 756.6, and 109.2 mg%, respectively). Glucose content was highly negatively correlated (p<0.01) with platycodin D, platycodin D3, and deapioplatycodin D (-0.924, -0.957, -0.861, p<0.01, respectively). These results suggest that the drying method affects the saponin content of P. grandiflorum and daylight and hot-air drying methods are more suitable and beneficial than freeze-drying.

• Journal of Korean Society of Forest Science
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• v.110 no.2
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• pp.244-253
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• 2021

This study aimed to investigate quality characteristics of hot-air dried persimmon during the drying period in 'Bansi' and 'Godongsi'. These cultivars were classified into four grades: 2L, L, M, and S based on the fruit weight. Weight loss, firmness, soluble solid content (SSC), and moisture contents were measured during the hot-air drying period. The weight loss significantly increased during the drying period (p<0.05), while there was no difference between cultivars. In the initial drying period, the firmness decreased due to softening during the ripening stage and increased significantly due to hardening during the water loss stage. Regardless of the cultivars, the SSC increased from 19.6% in the initial period to 55.3% at 12 days after drying. Moisture content statistically decreased in both cultivars over the whole drying period. It took 4 days and 8~10 days to produce semi-dried persimmon (45~55% moisture content) and dried persimmon (25~35% moisture content) in both cultivars. These results could be effectively used as basic data for producing high-quality semi-dried and dried persimmons using the hot-air drying method in 'Bansi' and 'Godongsi'.

• Food Science and Preservation
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• v.30 no.5
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• pp.868-874
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• 2023

This study aimed to investigate the drying characteristics of Caragana sinica Rehder flowers, which are basic data necessary for increasing utilization. The flowers were harvested in mid-April and dried at different hot-air temperatures (50-90℃), and the physicochemical properties of the dried flowers were analyzed. It was found that the drying rate was proportional to the air temperature. The visual color of dried flowers was relatively strong in green when dried at 50℃, while browning was relatively severe when dried at 90℃. The greenness (-a^* value) of the mechanical color of the powder decreased with increasing temperature, and the yellowness (b^* value) decreased with increasing temperature above 70℃. The soluble solids of the hot water extract were maintained at a certain level after increasing up to 70℃, and the pH decreased with increasing temperature. The total polyphenol contents tended to increase with increasing temperature, and DPPH radical scavenging activity did not show a significant change after increasing up to 70℃. These results suggest that the hot-air drying temperature had a significant effect on the physicochemical characteristics of the C. sinica flower. The appropriate hot-air drying temperature was judged to be less than 50℃ for maintaining the unique color, and approximately 70℃ considering the high hot-water extraction yield and antioxidant capacity.

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

• Korean Journal of Fisheries and Aquatic Sciences
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• v.7 no.3
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• pp.163-168
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• 1974

The present paper deals with the degradation of nucleotides in the muscle of sea mussel, Mytilus edulis, during drying. Three kinds of samples, raw, hot-air dried, and steamed-and-hot air dried were prepared and the contents of nucleotides were determined by ion exchange chromatography on columns of Dowex 1, X8. ATP and ADP were dominant in the raw muscle showed about $8{\mu}moles/g$, dry basis, respectively. The rate of degadation of ATP was very slow during drying compared with those of fish. The accumulation of ADP and AMP were observed during drying and the amount of total nucleotides (ATP+ADP+AMP) were not decreased remarkably by drying process. IMP was not detected in the all of the samples examined, however, the contents of inosine and hypoxanthine were increased during drying. In case of inosine contents, the hot-air dried sample marked an exceedingly high value equivalent to 8 times of the raw sample whereas steamed-and-hot air dried sample showed 2 times of raw samples.

• Korean Journal of Food Science and Technology
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• v.34 no.1
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• pp.13-17
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• 2002

The study was to analyze aroma patterns of Gastrodiae Rhizoma by the electronic nose with conducing polymer 32 sensors. Response by the electronic nose was analyzed by the principal component analysis (PCA). Sensory evaluation for the organoleptic characteristics of Gastrodiae Rhizoma was also performed. Raw Gastrodiae Rhizoma was very intensive in overall odor and taste. Hot air-dried $60^{\circ}C$ Gastrodiae Rhizoma was relatively weak in overall odor and taste. Intensity of aroma in the electronic nose was the highest in $60^{\circ}C$ hot air-dried Gastrodiae Rhizoma. As quality factor (QF) calcuated from PCA map of normalized pattern data by thirty two sensors showed less than 2, and so aroma pattern among raw, freezed-dried, and hot-air dried Gastrodiae Rhizoma had no difference. When PCA was performed for normalized pattern data by the selected sensitive ten sensors, QF value between raw and $60^{\circ}C$ hot air-dried Gastrodiae Rhizoma was 2.366. Thus aroma pattern of raw and $60^{\circ}C$ hot air-dried Gastrodiae Rhizoma was discriminated in electronic nose.

• Korean Journal of Food Science and Technology
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• v.20 no.3
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• pp.380-384
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• 1988

The coefficients of the hot-air and freeze dried garlic isotherms and the critical water activities of these were estimated to be 0.85-0.94 by the linear regression and 0.58-0.60 by the sensory evaluation and ${\Delta}E$ value. Water adsorption rate(K) of hot-air dried garlic packaged with $48{\mu}m$ low density polyethylene(LDPE) decreased from $0.12g\;H_2O/100g/day\;to\;0.093g\;H_2O$/100g/day with decreasing the package dimension from $0.051m^2\;to\;0.029m^2\;at\;40^{\circ}C$ and 75% RH, and that of freeze dried one decreased from $0.17g\;H_2O/100g/day\;to\;0.12g\;H_2O$/100g/day as the filling weight increased from 50g to 10g in the package of $0.051m^2$. Shelf-life of hot-air dried garlic packaged with $80{\mu}m$ LDPE were 99days at $40^{\circ}C,\;283day\;at\;30^{\circ}C\;and\;455\;days\;at\;15^{\circ}C$ in the 75% RH. The differences of water contents between predicted data with water vapor permeability of the conventional method and experimental data were 0-1.5% in the water content range of around 13-18%, but about 2 in the water content range of around 8-11%.

• Korean Journal of Food Science and Technology
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• v.41 no.2
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• pp.146-150
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• 2009

Sliced ginger samples were dried using 30, 50, and 80% maltodextrin, respectively, as a dehydrating agent. The moisture content of the maltodextrin-treated ginger decreased with increasing concentrations of maltodextrin. The dehydrated ginger was compared with hot air-dried and freeze-dried ginger samples in terms of rehydration ratio, gingerol content, color, and sensory characteristics. The rehydration ratio of the maltodextrin-treated ginger was superior to those of the hot-air dried or freeze-dried ginger. In addition, the maltodextrin-treated ginger had the highest content of 6-gingerol among the samples. Color as well as sensory scores for odor, texture, appearance, and overall acceptance were greater for the maltodextrin-treated ginger compared to the hot-air dried or freeze-dried ginger. These results indicate that drying ginger with maltodextrin is very efficient because good rehydration capacity is retained and minimal cell destruction can be achieved.

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

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.6
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• pp.973-980
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• 2000

This study was conducted to evaluate the quality of the cold air dried anchovies (CA), and compared with those of sun-dried anchovies (SA) and hot air dried anchovies (HA). Peroxide value increased, while ratio of percentage of (20:5+22:6) to that of 16:0 decreased during boiling and drying. The extents of change were CA>SA>HA in the order. In the case of CA, lightness was higher, but redness, yellowness and degree of browning was lower than in SA and HA. From the results of lipid properties, color test and sensory evaluation on color and rancidity odor, lipid deterioration was the lowest in CA of all boiled dried anchovy. Favorite properties such as a hot-water soluble nitrogen content and sensory evaluation on color and appearance of CA was superior to that of SA and HA. The nutritional properties (total amino acid contents, mineral contents and fatty acid compositions) of CA was similar to that of SA, but was superior to that of HA. Consequently, CA was recognized as a boiled dried anchovy with the most quality.