• Journal of the East Asian Society of Dietary Life
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• v.25 no.6
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• pp.1049-1057
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• 2015

This study investigated the physicochemical properties of Dioscorea batatas for improvement of biological activities during a three-step steaming process, steaming $120^{\circ}C$ for 30 min and hot air drying at $60^{\circ}C$ for 8 hrs. Samples were extracted with 70% ethanol and analyzed for free sugars, and organic acids were analyzed by HPLC. The DPPH & ABTS radical scavenging activities, crude saponin, water binding capacity, oil absorption, and ${\alpha}$-glucosidase activity were measured. The major free sugars in all samples were fructose, maltose, and sucrose, and the free sugar contents increased to 157~235% after the three-step steaming process compared to the control. Organic acid contents of samples treated by steaming increased to greater than 55.8 mg/100g. The ABTS radical scavenging activity significantly increased with repeated steaming process, especially after the three-step process. As the time of steaming process increased, DPPH radical scavenging activity increased from 26.99% fresh Dioscorea batatas to 80.46~97.79% after the three-step process. Crude saponin content increased rapidly as steaming time increased, but decreased after the three-step process steaming process. The water-binding capacities of the samples treated by steaming process were higher than that of the control, whereas oil absorption decreased as steaming time increased. From the results, steaming process could be suggested as beneficial for controlling fat intake. Compared to acarbose, a known antidiabetic drug, used as a positive control, ${\alpha}$-glucosidase inhibitory activity of samples treated by two-step steaming was among the samples. The results suggest that Dioscorea batatas treated by steaming process has antioxidative and anti-diabetis activities and can be used as a natural health product.

• Journal of the Korean Wood Science and Technology
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• v.44 no.5
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• pp.776-784
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• 2016

In this study, green Larix kaempferi lumber was heat-treated by using superheated steam (SHS) at a pilot scale and then various physico-mechanical properties of the heat-treated wood were evaluated and compared with the properties of conventional hot air (HA) heat-treated wood. Decay resistance of brown rot fungi and compressive strength parallel to the grain of the SHS heat-treated wood without occurrence of drying check from green lumber were increased. On the other hand, density, equilibrium moisture content, shrinkage, and bending strength of the SHS heat-treated wood were lower than those of the conventional HA heat-treated wood. Because heat transfer and thermal hydrolysis of SHS heat treatment was accelerated by a large amount of water, the effect of SHS heat treatment on the physico-mechanical properties was higher than that of HA heat treatment at the similar conditions of temperature and time. From the results of this study, because green lumber can be heat-treated without occurrence of cracks or checks by using SHS and similar heat treatment effect on the physico-mechanical properties of wood can be produced despite a low temperature or short time of heat treatment, it is expected that heat time and energy consumption could be reduced by using SHS.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.1
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• pp.51-57
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• 1992

The preservative effect of chitosan film packing on quality of lightly-salted and dried horse mackerel was studied. In preparation of chitosan film, blue crab shell chitosan was dissolved in dilute acetic acid$(1.0\%,\;v/v)$, filtered, and spreaded on plastic plate and dried at $50\pm2^{\circ}C$. The chitosan film thus obtained was neutralized with 1.0N NaOH for 2 hrs and dried at room temperature after washing several times with distilled water. The lightly-salted and dried horse mackerel product was prepared by drying for 4 hrs at $40\pm2^{\circ}C$ in hot air dryer after packing with the chitosan film. During storage at $5.0\pm0.5^{\circ}C$, moisture content of the product was higher than that of the reference, but contents of VBN(volatile basic nitrogen) , amino nitrogen, and TMA of the product on dry basis were lower than those of the reference. Viable cell count, TBA value, and peroxide value of the product were also lower than those of the reference. Judging from the result of sensory evaluation, the chitosan film packing in the storage of lightly-salted and dried horse mackerel was remarkably elongated shelf-life of the product. From the results of chemical and sensory evaluation, it was concluded that chitosan film packing was an effective method for retaining the quality of lightly-salted and dried horse mackerel.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.6 no.1
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• pp.17-27
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• 1996

This study was designed to survey exposure levels of formaldehyde among workplaces in some plywood industries and to compare three sampling methods including the impinger method(IM, NIOSH method No. 3500), the solid sorbent tube method(SS, NIOSH method No. 2541), and the passive bubbler monitor method(PB, SKC). The survey was conducted in seven particle board manufacturing factories, two resin manufacturing factories and two plywood manufacturing factories in Incheon area during the period from March 6 to April 20, 1995. The workplaces included were the hot/cold press, the roller/spreader, the soaking/drying, and the reaction/mixing areas. The results were as follows; 1. The average(GM, GSD) concentrations of formaldehyde by sampling methods were 0.11(4.43) ppm by IM, 0.27(2.03) ppm by SS, and 0.29(2.04) ppm by PB, respectively. The concentrations by 1M method were statistically very significantly lower than those of SS and PB methods, particularly at low air borne concentrations of formaldehyde (p<0.001). 2. The area average concentrations of formaldehyde by workplaces measured with PB bubblers were 0.23(2.08) ppm from the press, 0.23(1.77) ppm from the spreader, 0.24(1.51) ppm from the soaking, and 0.46(1.96) ppm from the reaction areas, respectively. The personal average concentrations of formaldehyde by workplaces measured with PB bubblers were 0.30(1.77) ppm from the press, 0.33(1.54) ppm from the spreader, 0.36(1.46) ppm from the soaking, and 0.84(1.19) ppm from the reaction areas, respectively. 3. No statistically significant differences of formaldehyde concentrations among workplaces except the reaction area(p<0.001) were found. 4. Formaldehyde concentrations from personal samples were higher than those of from area sam pies in all workplaces studied. But no statistically significant differences of formaldehyde concentrations both area and personal samples were found. In conclusion, this study found that although formaldehyde concentrations in some plywood industries in Incheon area were below the regulatory limit of 1 ppm, they were over the limits recommended by NIOSH and ACGIH. This study also suggests that the impinger method may underestimate true formaldehyde concentrations. It implies that there will be more workplaces not meeting current regulatory limit if either the solid sorbent or passive bubbler methods were used instead of the impinger method. It is suggested that passive monitors will be a reasonable alternative for area and personal sampling of formaldehyde if the accuracy and validity of passive monitors be verified before use.

• Journal of the Korean Home Economics Association
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• v.42 no.1
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• pp.167-180
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• 2004

This study was carried out to investigate quality characteristics of chopped garlic stored at various temperature. Chopped garlic was stored at room temp.($25^{\circ}C$), refrigerator temp.($5^{\circ}C$) and frozen temp. ($-18^{\circ}C$) for 1, 2, 4, 8, 24, 48, 72 hours(room temp.) and 1, 3, 5, 7, 10, 15, 20, 30 days(refrigerator temp. and frozen temp.), respectively. Brown color, Hunter color value, vitamine C contents and flavor patterns by electronic noes of chopped garlic were measured. Fresh chopped garlic was used as control and garlic powder by hot air drying was used for comparisons. Brown color of chopped garlic increased with increasing storage time, and the intensity of that was reduced as following order such as chopped garlic stored at room temp., refrigerator temp. and frozen temp. Brown color of garlic powder was most dark amomg all the samples. The results of Hunter color value was consistent with then of brown color in chopped garlic, whereas those of garlic powder showed relatively low browning. Above results might be caused by the difference of measurement as only surface color was measured in Hunter color value unlike brown color. Vitamine C contents of chopped garlic decreased with increasing storage time, and in particular those stored at room temp. decreased markedly as retention of those stored at room temp. was 60％ of control after 1 day storage. Vitamine C retention of chopped garlic stored at refrigerator temp. was 78％ of control after 10 day storage and that stored at frozen temp. was 86％ of control after 30 day storage. At room temp., flavor pattern by electronic nose showed a difference between chopped garlic stored for 1hour and control, and showed occurrence of off odor after 1 day storage. Flavor pattern of garlic powder by electronic nose showed a mild flavor. Flavor patterns of chopped garlic stored at refrigerator temp. were similiar until 10 day storage, whereas those showed occurrence of volitile components after 15 day storage. Flavor patterns of chopped garlic stored at frozen temp. were similiar after 30 day storage, and especially those after 3 day storage were almost the same as control. Therefore it is desirable to store chopped garlic within 1 day at room temp. and within 10 days at refrigerator temp. And it is most desirable to store chopped garlic at frozen temp. as retention of quality characteristics was superior than other storage temp.

• Korean Journal of Food Science and Technology
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• v.30 no.3
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• pp.542-547
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• 1998

In order to study bread properties utilizing extracts of pine needle, various mixing percentage were applied to select appropriate ratio between water and extracts. Dough pH, dough pH after first fermentation, dough volume, bread volume and baking loss rate were tested to investigate bread properties after adding extracts of pine needle to bread. The results were summarized as follows; The effects of extracts percentage on pH value of dough according to preparation method were the lowest in the method of hot air drying of pine needle powder. After first fermentation, dough pH was tended to have a the same tendency as above. Dough volume and bread volume were tended to be increased as extracts percentage of pine needle were increased. The percentage of baking loss tended to be a little increased as addition level of extracts was increased. Strength of hardness were increased as storage time passed away. In conclusion, the taste and texture of bread were tended to be decreased as storage time goes, but the strength of pine needle flavour were tended to be increased as addition level of extracts were increased, irrespective of preparation method.

• Korean Journal of Food Science and Technology
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• v.30 no.3
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• pp.615-623
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• 1998

The garlic juices were extracted and concentrated by heating at $90^{\circ}C$, by using a rotary vacuum evaporator at $45^{\circ}C$, or by freezing at $-50^{\circ}C$ until the volume was reduced to 70% of the original volume. The concentrated juices were kept at $4^{\circ}C\;or\;25^{\circ}C$ for 60 days and the changes of bacteria and color were monitored every 10 days. Flavors of the raw garlic juices, concentrated garlic juices, and garlic powder by hot-air drying were analyzed monthly using GC and GC/MS. The CFUs/mL of mesophilic and psychrotrophic bacteria in the garlic juice concentrated at $90^{\circ}C$ were lower about 1 to 2 log cycles than those of other concentrated juices. Hunter L, a, and b values in the raw garlic raw juice and the juice concentrated at $-50^{\circ}C$ significantly increased at the beginning of storage, in particular, when they were stored at $25^{\circ}C$. The garlic juice concentrated at $45^{\circ}C$ showed relatively low L value but the juice concentrated at $90^{\circ}C$ showed high a value. The main peaks in chromatograms of volatile components identified by GC/MS were 3,3'-thiobis-1-propene, di-2-propenyl disulfide, 3-(methylthio)-1-propene in the raw garlic juice and the concentrated juices, and the juices concentrated at $45^{\circ}C\;or\;-50^{\circ}C$ showed relatively high preservation of garlic flavor.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.7
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• pp.921-925
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• 2007

In order to optimize microbial safety and preservation in quality retention of rice flour, commercial hot-air dry (HT, 65/15 min) and microwave dry (MT, 700 watt/30 sec) treatments were developed, and in this study, natural microflora present in rice flour exposed to different storage temperature and periods were monitored. Changes in color (E) appeared to be less on the MT rice flour than on the rice flour. Effectiveness of the MT treatment showed reduction rates for total aerobic bacteria (2.62 log CFU/g), yeasts, and molds (0.37 log CFU/g). Total aerobic bacteria showed similar growth patterns of all the treatments during storage; however, the MT treatment inhibited the growth of this organism in rice flour. In conclusion, the MT treatment was found to be a suitable drying method to substitute the HT treatment in terms of quality of rice flour and microbial safety.

• Journal of the Korean Society of Food Science and Nutrition
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• v.12 no.2
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• pp.176-187
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• 1983

Volatile flavor components of garlic and factors which influence on its flavors were reviewed. Growth, storage and processing conditions influence on the flavor intensity of garlic. To intensify garlic flavors, it is desirable that sufficient sulfate nutrition be supplied to the soil of growing garlic and that the suggested proportions of mineral composition and water content be considered. And to maintain the flavor intensity of post harvested garlic, flavor losses taken place during over inter storage mainly due to respiration, sprout and decay, have to be minimized. Among the various storage methods, combination method of post harvest hot-air drying and low temperature ($0^{\circ}C$), low humidity (RH 70-75%) is useful. The flavor of processed garlic is very much decreased as compared with that of fresh, and the decreasing rate of flavors depends on processing method. The synthetic garlic flavors were obtained by three types based on intermediate thiosulfinate, S-alk(en) yl-$\small{L}$-cyteine sulfoxlde-alliinase fission products and $\small{L}$-5-alk (en)yl thiomethylhydantoin ${\pm}$ S-oxides. These synthetic garlic flavors may be promised to be applied to food additives.

• Journal of Ginseng Research
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• v.31 no.4
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• pp.222-229
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• 2007

Changes on physicochemical properties of fresh Korean ginseng during repeated 9 times steaming processes, steaming $90{\sim}95^{\circ}C$ for $1{\sim}3\;hr$ followed by hot air-drying at $50^{\circ}C$ for $36{\sim}48\;hr$, were investigated. The water contents decreased from 73.4% of fresh ginseng to 13.7% finally. The final yields in bases of total weights and dry matter were 21.0% and 79.0%, respectively. As the times of steaming processes increased, lightness (L value) decreased and redness (a value) increased in color of ginseng powder. Browning index also rapidly increased after 3 times of steaming process in particular. Total water soluble sugar contents decreased from 55.4% in fresh to 38.6% in final processed ginseng, but acidic polysaccharide contents increased by about 50% with increasing times of steaming process. Total phenolic compound contents significantly increased with repeated steaming processes especially after 5 times of steaming processes and crude saponin contents also increased in some degree. In the case of major ginsenosides, the contents of $Rb_1$, $Rb_2$, $Rg_1$, Re (representative ginsenosides in fresh ginseng) decreased, but those of $Rg_2$, $Rh_1$, $Rg_3$ (unique ginsenosides in red ginseng) increased after especially 5 times of steaming processes.