• Journal of the Korean Society for Heat Treatment
• /
• v.11 no.1
• /
• pp.62-72
• /
• 1998

High carbon steel is used for rails due to the excellent wear resistance, however the welding of high carbon steel is more difficult than that of mild steel owing to the high hardenability and sensitivity to cracking at the weldment. In this study, the impact toughness and cracking behavior of a rail weldment were evaluated as function of preheating temperatures. Impact toughness were more excellent in the specimen welded with preheating temperature above $250^{\circ}C$ than that below $100^{\circ}C$, and cracks were not detected in the specimen welded with preheating temperature above $250^{\circ}C$.

• Journal of Ginseng Research
• /
• v.28 no.3
• /
• pp.136-142
• /
• 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 Society for Precision Engineering
• /
• v.31 no.1
• /
• pp.29-33
• /
• 2014

Recently, Difficult-to-cut materials are used in many manufacturing industry. But the difficult-to-cut materials are difficult-to-cutting process. So difficult to cut material cutting process was used after heat treatment through preheating for easy cutting process. In this study, Inconel 625 was preheating using laser heat source in computer simulation. Laser heat source temperature applied $1290^{\circ}C$ that suitable preheating temperature for Inconel 625. And temperature effects such as temperature distribution for moving heat source studied apply to similar actual process condition. Simulation results for heat treatment effects through temperature distribution verified.

• Journal of the Korean Society of Food Culture
• /
• v.14 no.5
• /
• pp.461-466
• /
• 1999

As a part of investigation to use sardine(Sardinops melanoslicta) more effectively as a food source, this study was undertaken the processing condition of rapid- and low salt-fermented liquefaction of sardine. To prepare rapid fermented products, the chopped whole sardine was added 8% NaCl and then preheating treatment at $40^{\circ}C,\;45^{\circ}C$ and $50^{\circ}C$ in the manufactured fermenter(180L) for 9 hrs, and then fermentation at $33^{\circ}C$ for 90 days. The chemical changes such as amino nitrogen(amino-N), volatile basic nitrogen(VBN), and histamine in the hydrolysates of fermented sardine were analyzed as well as viable cell count and organoleptic evaluation during fermentation to compare the quality between control and preheating samples. During fermenting, the amino-N in the hydrolysates increased rapidly during the first 30 days and slowly thereafter. The highest content of amino-N appeared at 75 days in control sample and $60{\sim}75$ days in preheating samples. The changes of VBN in the hydrolysates increased rapidly during first 15 days in control samples and 30 days in preheating samples. However they were generally low level in preheating samples. Histamine content in the hydrolysates of the control samples increased markedly after 15 days, but preheating samples were generally low level, and then $75{\sim}90$ days of fermentation reached to the maximum which was about $2.0{\sim}3.0$ times lower than that of control samples. As for the organoleptic flavor evaluation, the control and preheating at $40^{\circ}C$ samples were unpleasant odor after 15 and 60 days, respectively. But preheating at $45^{\circ}\;and\;50^{\circ}$ samples were fresh odor after 90 days fermentation.

• Food Science of Animal Resources
• /
• v.36 no.5
• /
• pp.671-678
• /
• 2016

Fractioning and/or preheating treatment on the rheological properties of myofibrillar protein (MP) gels induced by microbial transglutaminase (MTG) has been reported that they may improve the functional properties. However, the optimum condition was varied depending on the experimental factors. This study was to evaluate the effect of red bean protein isolate (RBPI) on the rheological properties of MP gels mediated by MTG as affected by modifications (fractioning: 7S-globulin of RBPI and/or preheat treatment (pre-heating; 95℃/30 min): pre-heating RBPI or pre-heating/7S-globulin). Cooking yields (CY, %) of MP gels was increased with RBPI (p<0.05), while 7S-globulin decreased the effect of RBPI (p<0.05); however, preheating treatments did not affect the CY (p>0.05). Gel strength of MP was decreased when RBPI or 7S-globulin added, while preheat treatments compensated for the negative effects of those in MP. This effect was entirely reversed by MTG treatment. Although the major band of RBPI disappeared, the preheated 7S globulin band was remained. In scanning electron microscopic (SEM) technique, the appearance of more cross-linked structures were observed when RBPI was prepared with preheating at 95℃ to improve the protein-protein interaction during gel setting of MP mixtures. Thus, the effects of RBPI and 7S-globulin as a substrate, and water and meat binder for MTG-mediated MP gels were confirmed to improve the rheological properties. However, preheat treatment of RBPI should be optimized.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.30 no.4
• /
• pp.15-25
• /
• 2022

In this study, the efficiency of treatment of moisture and organic matter in food waste was analyzed according to the air blast volume and preheating using the bio-drying method. Te mount of air blast volume and preheating were determined by the evaluation of temperature and CO2 during food waste treatment using the bio-drying method. As a results, the increase in the air blast volume increased the moisture removal efficiency and removal rate, but, lowered the temperature inside the bio-drying by the decease in microbial activity. In order to maintain the activity of microorganisms, it was estimated that it was necessary to inject an appropriate air blast rate according th the properties of the food waste. In this study, the injection of air blast volume at 15L/min was optimal. It was evaluated that the organic matter and water removal rates according to the presence or absence of air preheating, the organic matter removal rate and water removal rate increased by 3-5% when air preheating was not performed. Also, there was no internal aggregation caused by the generation of condensate inside the bio-drying. Therefore, for effective bio-drying of food waste, it is necessary to maintain an appropriate air blast volume to maintain microbial activity, and it is considered that injection through preheating of air is required.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.23 no.4
• /
• pp.327-332
• /
• 2010

We report on the effect of PET substrate preheating on the characteristics of the flexible and transparent indium tin oxide (ITO) electrode grown by a specially designed roll-to-roll sputtering system for touch panel applications. It was found that electrical and optical properties of the roll-to-roll sputter grown ITO film were critically dependent on the preheating of the PET substrate. In addition, the roll-to-roll sputter-grown ITO film after post annealing test at $140^{\circ}C$ for 90 min showed stable electrical and optical properties. The low sheet resistance and high optical transmittance of the ITO film grown on the preheated PET substrate demonstrate that the preheating process before ITO sputtering is one of the effective way to improve the characteristics of ITO/PET film. Furthermore, the superior flexibility of the ITO electrode grown on the preheated PET substrate indicates that the preheating treatment is a promising technique to obtain robust ITO/PET sample for touch panel applications.

• Korean Journal of Food Science and Technology
• /
• v.17 no.6
• /
• pp.447-453
• /
• 1985

The effects of preheating and calcium chloride on prevention of tissue softening was examined during fermentation and storage of radish root kimchi. In order to find the optimum condition of preheating treatment, activities of pectinesterase (PE) and polygalacturonase (PG) in radish root were measured with respect to $CaCl_2$ concentration and temperature. A maximum firmness was obtained with treatment in 0.05M $CaCl_2$ at $55^{\circ}C$ for 2hr which was optimum conditions for PE activity, while PG was inhibited at the $CaCl_2$ concentration of 0.05M. Firmness of radish root kimchi prepared by preheating treatment was decreased little during fermentation and storage for 25 days.

• Korean Journal of Food Science and Technology
• /
• v.28 no.2
• /
• pp.393-395
• /
• 1996

This study was conducted to investigate the effect of infusion of pectinesterase (PE) along with preheating treatment in $CaCI_2$ solution on softening Kimchi tissue. Preheating treatment showed preventive effect on softening of Kimchi tissue. Especially, the preheating in the presence of P was more effective in preserving firmness of both stem and leaf. As for of effect of PE infusion by vacuum treatment, a maximum crispness was obtained from the vacuum-treated stems in 0.05 M $CaCI_2$ solution containing PE. The crispness of all the samples decreased during fermentation and the PE-infused samples by vacuum treatment showed higher crispness than the control until the fourth day of fermentation.

• Journal of the East Asian Society of Dietary Life
• /
• v.14 no.3
• /
• pp.283-287
• /
• 2004

To investigate the effects of preheating treatment on the properties of salt-preserved cucumber, cucumber were heated in the warm water to 40, 60, and 75$^{\circ}C$ for 15 min. Thereafter, cucumbers were cooled and the ratios of cucumbers: water was adjusted to 1:1.2(w/w) and salt was added to have final salt concentration of 12%. The group which was heated to 6$0^{\circ}C$ showed the highest scores on hardness followed by 4$0^{\circ}C$, no-heat, and 75$^{\circ}C$ treated groups after 60 days of salt-preservation. The yellowness on the surface of cucumber peels was getting intense as temperature was increased during heat treatment, which resulted in the most intense yellowness in no-heat and 4$0^{\circ}C$ treated groups. The intensities of greeness and redness of the groups also differed according to different temperature applied during heat treatments. Regardless of heat treatment, no difference in the absorbance of isopropyl alcohol extracts were found. Activities of pectinesterase were the highest in 6$0^{\circ}C$ treated group followed by 4$0^{\circ}C$, 75$^{\circ}C$, and no-heat treated group until 60 days of preservation, while activities of polygalacturonase in 4$0^{\circ}C$ and 6$0^{\circ}C$ treated groups were lower.