• Korean Journal of Medicinal Crop Science
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• v.16 no.5
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• pp.332-336
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• 2008

PPD ginsenosides in ginseng leaf were analyzed to determine effects of either FIR heat or steaming heat treatment. Among the PPD ginsenosides, Rb1, Rc and Rb3 forming four glycoside-attached aglycons were increased as FIR heat temperatures were increased from 60 to $120^{\circ}C$, while Rb3 was decreased. In addition, FIR heat treatment was effective to increase Rd forming a three glycoside-attached aglycon. Rg3 and Rh2 were not increased by the FIR heat treatment. In steaming heat treatment, Rb1 was significantly decreased, while Rb2 was increased. Rd was also increased by increased steaming temperature, yet its content was lower than in the FIR heat treatment. However, the steaming heat treatment increased yields of Rg3 and Rh2, which were not observed in the FIR heat treatment. Thus, FIR heat treatment was beneficial to efficient products of Rb1, Rc, Rb3 and Rd. Steaming heat treatment was effective to higher collection of Rb2, Rg3 and Rh2.

• Journal of the Korea Furniture Society
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• v.11 no.2
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• pp.1-6
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• 2000

This study was carried out to investigate the effect of steaming on mechanical properties of heat-compressed wood specimens. The specimens for this mechanical strength tests were prepared to super-heated steam treatment after compression to the radial direction of sonamu (Pinus densiflora). The specimen's size is $50(L)mm{\times}20(R)mm{\times}17(T)mm$. Steaming temperature and treatment time is $120^{\circ}C$ and 20, 40, 60, 80, 100 minutes, respectively. Modulus of elasticity(MOE) in compressive test is directly proportional to steaming time. On the other hand, modulus of elasticity in bending test between steaming and not steaming after heat-compressed wood is similar irrespective of steaming time. The reason for this phenomenon is not clear yet.

• Journal of the Korean Wood Science and Technology
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• v.29 no.4
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• pp.9-15
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• 2001

This study deals with shear strength test for Pinus densiflora and Pinus radiata treated at above $100^{\circ}C$ by heat steam. Treatment conditions of this experiment were operated at regular intervals of $20^{\circ}C$ at temperatures up to $200^{\circ}C$ for 5, 10, 20 and 30 minutes by using the steam-explosion apparatus. It was examined, at high temperatures, degradation of some compounds from wood composition could lead to reduced the shear strength through heat steaming processes and play a large part in the plastic process of solid wood materials. It could be estimated that the shear strength of woods were gradually reduced by heat steaming time. Remarkable reduction of shear strength of woods was observed with increasing steaming temperatures above 10 minutes steaming time. Furthermore, this phenomenon shows a tendency to increase with higher temperatures. Therefore, it was considered that the softening by steaming treatment at high temperatures is necessary for the improvement on the wood processing ability.

• Preventive Nutrition and Food Science
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• v.9 no.4
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• pp.330-335
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• 2004

Changes in functional constituents of rice germ prepared using three different heat pretreatments: roasting, steaming and microwave heating, were determined and compared with those of non-treated rice germ. The yield of rice germ oil increased generally and then decreased with increasing time for all three heat pretreatments, although the yields of rice germ oil varied among the three heat pretreatments. There were no major differences in fatty acid compositions among the rice germ oils subjected to the three different heat pretreatments. Levels of $\alpha$-tocopherol in rice germ oil increased up to about 1.5 times at 3 min of roasting and microwave heating, compared to control, and then decreased with increasing treatment time, but $\alpha$­tocopherol concentrations in rice germ oil gradually decreased with increasing steaming time. The contents of three phytosterols ($\beta$-sitosterol, stigmasterol and ergosterol) decreased progressively with increases in roasting and steaming time, while concentrations of the three phytosterols increased up to - 15$\%$ with 3 min of microwave process as compared to control, and then decreased thereafter. Levels of $\gamma$-oryzanol in rice germ oil decreased gradually with increasing time during all three different heat pretreatments. However, levels of $\gamma$ -aminobutyric acid (GABA) in rice germ decreased gradually with increasing roasting time, while those of GABA increased greatly up to about 2 times after 10 min of steaming process, and then decreased slowly thereafter. During microwave heating, the contents of GABA increased at 3 min of treatment time and then decreased. These results suggest that microwave heating may be the most suitable processing method to preserve functional constituents in rice germ.

• Journal of the Korean Home Economics Association
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• v.23 no.2
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• pp.29-36
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• 1985

This experiment was conducted to investigate changes of the components in steamed and roasted green tea after 10 min, 20 min and 30 min of heat treatment of heat treatment at $110^{\circ}C$. Vitamin C and tannin were determined by spetrophotometry. Total nitrogen, water-soluble nitrogen and water-soluble non protein nitrogen were determined by Kjeldahl analysis system. Aromas were identified by gas chromatography. After heat treatment, contents of most compounds decreased. Tannin and caffeine decreased a little bit, while vitamin C decreased considerably. There were both decreases and increases in aromas. Aromas which increased were geraniol, trans-2-hexenol, linalool, $\alpha$-ionone and $\beta$-ionone. From these results, it was concluded that the highest quality of green tea was one steam- treated for 10 min at $110^{\circ}C$.

• Journal of Ginseng Research
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• v.28 no.3
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• pp.143-148
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• 2004

Brown color intensity has been a major factor to estimate the quality of red ginseng and its products. This study deals with the relationship between the browning reaction of ginseng root and two compounds, arginyl-fructosyl-glucose(Arg-fru-glc) and arginyl-fructose (Arg-fru), in the model system of steaming and heat-drying processes for the preparation of red ginseng. During the steaming process, a marked decrease of starch and a considerable formation of maltose occurred in main roots of raw ginseng, but the formation of glucose was scarcely observed. After the heat-drying process, the brown color intensity of the powdered preparation of steamed main roots was 3 to 4 times higher than that of the powdered preparation of raw main roots. Also, when the heat- drying process was done with the addition of L-arginine, brown color intensity of the powdered preparation of steamed main roots was 12 to 13 times higher than that of the powdered preparation of raw main roots. The amount ratios of browning reaction products formed from sugar compounds and amino acids in the model system of steaming and heat-drying treatments in vitro were in order of xylose > glucose > fructose > maltose > dextrin (DE 9) > sucrose > dextrin (DE 8) and soluble starch. Each solution of Arg-fru-glc and Arg-fru that were synthesized chemically from maltose plus L-arginine and glucose plus L-arginine, respectively, changed from colorless to brown color during the heat-drying treatment. Amino acids or sugars were effective on the acceleration of each browning reaction of Arg-fru-gIc and Arg-fru during the heat-drying treatment.

• Journal of Ginseng Research
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• v.28 no.3
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• pp.136-142
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• 2004

During our investigations on the relationship between the browning reaction of ginseng root and two compounds (arginyl-fructosyl-glucose and arginyl-fructose) in the model system of steaming and heat-drying processes for the preparation of red ginseng, the preheating treatment of main roots of raw ginseng at 60∼70$^{\circ}C$ prior to the steaming and heat-drying processes was found to bring about the gelatinization of starch granules. The enzymatic hydrolysis of gelatinized starch to maltose, a marked formation of maltose, and the increase of both free arginine and total amino acids, resulting the acceleration of the Maillard type-browning reaction of ginseng root during the steaming and heat-drying processes, and the rise of brown color intensity of red ginseng. These results show that the preheating treatment may be effective for the decrease of inside white of red ginseng.

• Journal of the Korean Wood Science and Technology
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• v.33 no.4 s.132
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• pp.30-37
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• 2005

Heating and Steaming treatments were carried for deresinning and color change of radiata pine juvenile wood. The boards of 20 mm and 30 mm thicknesses were heat-treated at $150^{\circ}C$ and $220^{\circ}C$ for 2, 4 and 6 hours and steamed at $100^{\circ}C$ for 6, 24 and 48 hours. For extracting residual resin in treated boards and measuring wood surface color, alcohol-benzene solution and a portable colorimeter were used, respectively. The board of 20 mm thickness were deresined effectively by heating at over $150^{\circ}C$ for 2 hours or steaming for 6 hours while that of 30 mm thickness by steaming for 48 hours. For the board of 30 mm thickness treatment time was more influencing on deresinning than treatment temperature. The steamed boards showed higher $L^*$ than the heat-treated for both thicknesses. $L^*$ decreased with the increase of treatment temperature and time, but for the board heat-treated at $220^{\circ}C$ it didn't change after 4 hours. The surface color of the boards heat-treated at $220^{\circ}C$ for 4 and 6 hours were obviously changed, but those at $150^{\circ}C$ were not. It was revealed that the core of the heat-treated board was color changed as well as the surface.

• Preventive Nutrition and Food Science
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• v.9 no.2
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• pp.144-149
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• 2004

Changes in functional constituents of grape (Vitis vinifera) seeds prepared by three different heat pretreatments were determined and compared with those of non-treated grape seed. The recovery of grape seed oils was generally increased by roasting, steaming and microwave processes, although the recovery of specific constituents varied among three heat pretreatments. The recovery of MeOH extracts of the seeds increased following the roasting process, whereas that of MeOH extracts decreased gradually with steaming and microwave treatments. Levels of four catechins in grape seeds: (+)-catechin, procyanidin B$_2$, (-)-epicatechin, and (-)-epicatechin gallate, were decreased with increased roasting and steaming time, but were unaffected by microwave treatment. During the three different heat pretreatments, levels and compositions of fatty acid did not change, whereas those of phytosterol compositions decreased greatly. These results suggest that a mild heat pretreatment, controlled for temperature and time, is needed to prevent a considerable loss in the level of valuable functional components in grape seed.

• The Korean Journal of Food And Nutrition
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• v.25 no.1
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• pp.50-56
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• 2012

This paper examines the effects of various methods of soft steaming(i.e., forced convection-boiler, forced convection-fan, and natural convection) on the quality of potatoes. In particular, the paper investigates the effects of cooking conditions (the steaming method, the treatment time, and the temperature) on the color(L, a, b), moisture content, texture profile, and ascorbic acid of potatoes. The results indicate that not only the cooking method, the treatment time, and the temperature but also the heat transfer mechanism had considerable influence on potato quality. In addition, natural convection steaming was superior to other treatment methods in terms of nutrient retention and texture maintenance. The results of this study should be useful for establishing commercial standards for processing potatoes and improving the quality of thermally processed foods.