• 한국약용작물학회지
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• 제16권5호
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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.

• 한국가구학회지
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• 제11권2호
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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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• 제29권4호
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• pp.9-15
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• 2001

본 연구는 $100^{\circ}C$ 이상의 고온영역에서 증기처리에 의한 소나무(Pinus densiflora)재와 라디아타소나무(Pinus radiata)재의 전단강도를 조사하였다. 본 연구에서 사용한 열처리 조건은 온도조건 $100^{\circ}C$부터 $200^{\circ}C$까지 $20^{\circ}C$ 간격으로 6조건과 시간조건 5, 10, 20, 30분의 4조건이었으며, 폭쇄처리기를 사용하였다. 고온에서 증기처리에 의해 목재구성요소의 감소가 전단강도의 감소로 나타나고 목질재료의 광범위한 가소화를 진행시키는 것으로 판단된다. 목재의 전단강도는 증기처리시간에 따라서 점차적으로 감소한다는 것을 알 수 있었다. 10분 이상의 증기처리시간일 경우 온도가 올라갈수록 전단강도의 감소가 눈에 띄게 커졌다. 고온에서 증기처리에 의한 연화는 목재가공성 향상에 필요하다고 생각된다.

• Preventive Nutrition and Food Science
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• 제9권4호
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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.

• 대한가정학회지
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• 제23권2호
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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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• 제28권3호
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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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• 제28권3호
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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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• 제33권4호통권132호
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• pp.30-37
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• 2005

라디에타 파인 유령목의 수지를 제거하고 재색을 변화시킬 수 있는 열처리와 증기처리 방법의 적정 조건을 찾기 위해 본 연구를 수행하였다. 공시판재는 두께 20 mm와 30 mm를 사용하였다. 열처리는 $150^{\circ}C$와 $220^{\circ}C$에서 2, 4, 6시간, 증기처리는 $100^{\circ}C$에서 6, 24, 48시간 실시하였다. 잔류수지는 알콜-벤젠 용액으로 추출하였으며 휴대용 분광 색차계를 사용하여 재색을 측정하였다. 두께 20 mm 판재는 $150^{\circ}C$ 이상에서 2시간 열처리 또는 6시간 증기처리로, 두께 30 mm는 48시간 증기처리로 좋은 수지제거효과를 얻었다. 두께 30 mm 판재의 수지제거에는 처리시간이 가장 영향이 컸다. 판재 두께에 상관없이 백색도는 증기처리가 가장 높았으며 처리온도가 증가할수록, 처리시간이 길어질수록 감소하였는데 후자보다 전자에 더 영향을 받는다고 할 수 있다. 온도 $220^{\circ}C$에서 4시간 이상 열처리하더라도 백색도는 더 이상 변화하지 않았다. 온도 $220^{\circ}C$의 4시간과 6시간 열처리재는 재색이 분명하게 변하였으나 온도 $150^{\circ}C$의 열처리재는 12시간에서만 약하게 변하였다. 따라서 $150^{\circ}C$ 열처리로는 색상변화를 기대하기 어려울 것으로 생각된다. 열처리를 통해 표층뿐만 아니라 내층까지도 표층과 동일한 색상으로 변화시킬 수 있음이 증명되었다.

• Preventive Nutrition and Food Science
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• 제9권2호
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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.

• 한국식품영양학회지
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• 제25권1호
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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.