• Korean journal of food and cookery science
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• v.15 no.5
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• pp.475-482
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• 1999

This study was carried out to prepare green tea by traditional roasting process, Kujeungkupo, and to determine its sensory characteristics. The carotenoid content in green tea was increased by roasting and reached 1,317 mg/100 g by Kujeungkupo. Of all carotenoids, the contents of lutein and $\beta$-carotene were 1,170 mg/100 g and 111.1 mg/100 g, respectively. The total cathechin content in green tea was 14.57 g/100 g after 9th roasting. The more the number of roasting the little contents of cathechin in green teas. Of all cathechin, epigallocathechingallate was the highest(6.80g/100 g) followed by epicathechingallte and epicathechin. total cholrophyll content was 141 mg/100 g of green tea. The free sugar content in Kujeungkupo green tea wet 2.18 g/100 g, of which sucrose comprised 46% (1.01 g/100 g). The color value ($\Delta$E) of Kujeungkupo green tea was 16.25. In sensory evaluation, sweet taste was the highest in green tea roasted 3 times and the flavor was best in that roasted 5 times. The sweet and astringent tastes of green tea had negative relationships with a and b values. The content of cathechin in green tea had a negative relationship with sweet taste and a positive relationship with astringent taste.

• Korean journal of food and cookery science
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• v.13 no.3
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• pp.356-363
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• 1997

Soybean Da-sik was prepared with various soybean powder processing methods (roasting, steaming, and steaming followed by roasting) and sugar types (honey, oligo-sugar), and their sensory and physical characteristics were evaluated to determine the optimum preparation method. The results were as follows: 1. For Sample 1 (roasting soybeans for 30 min at 150$^{\circ}C$ and grinding), the best appearance of Da-sik was obtained when the content of honey was adjusted to 35 g, and the color with 30 g of oligo-sugar by sensory evaluation. The optimum texture was obtained with 40 g of honey, and the optimum chewiness with 30 g of honey Overall, the optimum quality was obtained with 35 g of honey, and oligo-sugar seemed to have less influence on the quality. In case of Sample 2 (four rounds of steaming and drying for 35 min), 40 g of oligo-sugar was found to exhibit the best quality, and honey was less effective. For Sample 3 (three rounds of drying followed by 15 min roasting at 150$^{\circ}C$), the best appearance and color were obtained with 35 g and 40 g of honey, respectively. The texture was most favorable with 40 g of honey, while the chewiness was best with 30 g of honey, suggesting 35 g of honey was the optimum level for Sample 3 soybean powder than oligo-sugar. 2. The springiness, gumminess, hardness and chewiness measured by a texture analyser were highest with Sample 1 containing 30 g of honey, and the cohesiveness with 40 g of honey. 3. For color, the best brightness and yellowness were obtained with Sample 1 with 30 g of honey. The redness was highest with Sample 3 with 40 g of honey. Overall, the desirable recipe for soybean Da-sik was 35 g of honey for Sample 1 and Sample 3, and 40 g of oligo-sugar for Sample 2.

• Korean Journal of Food Science and Technology
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• v.21 no.4
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• pp.575-582
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• 1989

An investigation was carried out to improve the quality and yield of barley tea(water extracts) by modifying the roasting method. The modified methods employed were crushing the barley into 4-10 parts and soaking in water at room temperature for 20 minutes followed by roasting (light brown or dark brown) at $250^{\circ}C$ before boiling with water. The varieties of barley used for this study were Ol-bori(with hulls) and Youngsan-bori(without hulls) and the qualities measured were the physical, chemical and sensory characteristics of roasted barley and its extracts. The results showed that the higher solid yields in barley tea was obtained with an increase in soaking and roasting time. The solid yields increased rapidly with extraction time in boiling water until 30 minutes and then slowed down thereafter. However the intrinsic viscosity of barley tea was reduced by increase in soaking and roasting time. The color of barley tea expressed as Hunter L, a, b values showed that lower L value and higher a and b values were measured for those prepared without soaking and with more extensive roasting. Organoleptic evaluation clearly showed that the sensory quality of barley tea was significantly improved in intensity of odor and taste by crushing, soaking and dark brown roasting.

• Journal of Radiation Industry
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• v.6 no.4
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• pp.311-316
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• 2012

The purpose of this study was to compare the sensory effects of different culinary methods such as electric pan cooking and charcoal roasting on gamma irradiated ready-to-eat chicken at 10 kGy. Evlauation of sensory properties were measured by estimating the organoleptic characteristics and physicochemical properties (TBARS, hardness and color different matters). The results showed that gamma irradiation after charcoal-roasting could more effectively moderate the decrease of sensory qualities and reduce off-flavor of ready-to-eat chicken than gamma irradiation after following electric pan cooking. These results suggest that gamma irradiation after charcoal broiling can be an effective culinary method for the preparation of ready-to-eat chicken.

• Resources Recycling
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• v.13 no.3
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• pp.27-36
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• 2004

Nickel oxide was recovered through roasting of a spent catalyst for hydrogenation reaction. Nickel on Kieselguhr catalysts were prepared by a precipitation method after a treatment of the recovered-nickel oxide with an acid. Effects of roasting temperature of the spent catalyst on recovery of nickel oxide was investigated. Most of nickel oxide could be recovered through roasting of the spent catalyst at $1000^{\circ}C$. In regeneration of catalysts by the precipitation method after the treatment of nickel oxide with an acid, the effect of promoter, precipitation condition and reduction condition on catalytic performance in vegetable oil hydrogenation were investigated. The addition of CaO or $Ce_2$$O_3$ resulted in an increase of catalytic activity.

• Korean journal of food and cookery science
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• v.31 no.5
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• pp.581-587
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• 2015

This study was conducted to investigate the antioxidative and antimicrobial activities of Korean dandelion (Taraxacum coreanum). Water extracts, ethanol extracts and methanol extracts were used to examine the free radical scavenging activity, total flavonoid content, total polyphenol content and antimicrobial activity. The free radical scavenging activity, total flavonoid, total polyphenol and total antioxidant activity of the water extracts were higher than those of the other extraction solvents. The antimicrobial activties of Korean dandelion extracts were examined on several food borne illness microorganisms using the paper disc diffusion method. Inhibition zones were observed on Staphylococcus aureus subsp. aureus, Listeria monocytogenes, Bacillus subtilis, Bacillus cereus and Escherichia coli in ethanol extracts. Inhibition zones were also observed on Listeria monocytogenes in water extracts. The physico-chemical properties of Korean dandelion tea according to the roasting time and soaking amount of tea were studied. The pH of the dandelion tea significantly decreased while the soluble solid contents significantly increased with increased roasting time (p<0.01). The lightness of the dandelion tea decreased and the turbidity increased with increased roasting time. In sensory evaluation, the sensory scores for the color, flavor and total acceptability were highest in the 40 min roasted tea. These results suggest that the water extract of Korean dandelion could be used as an antioxidative and antimicrobial functional food source. The optimum roasting time for Korean dandelion tea was 40 min at $200^{\circ}C$.

• 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.

• Food Science and Preservation
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• v.15 no.4
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• pp.556-561
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• 2008

This study was carried out to identify the cause of benzo(a)pyrene[B(a)P] production during the manufacture of sesame oil and perilla oil, and to minimize such B(a)P synthesis. The distribution of B(a)P in sesame seed and perilla seed differed with seed-growing district, the range was $0.06{\sim}0.31{\mu}g/kg$ in domestic seed and $0.12{\sim}0.47{\mu}g/kg$ in imported seed. B(a)P contents after roasting at $220^{\circ}C$ for 20 min in sesame seed and perilla seed were $1.87{\sim}2.47{\mu}g/kg$ and $2.12{\sim}2.43{\mu}g/kg$, respectively, and levels in oils obtained from the roasted seeds were $3.68{\mu}g/kg$ and $4.64{\mu}g/kg$, respectively. These data refer to seeds subjected to codsed roasting. With open roasting, the levels were $0.63{\mu}g/kg$ and $0.56{\mu}g/kg$, respectively. Closed roasting resulted in absorption of B(a)P, with consequent high levels in oils. We introduced forced ventilation during closed roasting. We tested various methods to remove B(a)P from sesame oil and perilla oil. Neither centrifugation nor filtering with diatomite and diatomiteactive carbon removed B(a)P. A filtering method using active carbon was effective. But this method adversely affected the color and flavor of sesame oil and perilla oil.

• Resources Recycling
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• v.30 no.6
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• pp.43-52
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• 2021

In this study, the optimal nitration process for selective lithium leaching from powder of a spent battery cell (LiNi_xCo_yMn_zO₂, LiCoO₂) was studied using Taguchi method. The nitration process is a method of selective lithium leaching that involves converting non-lithium nitric compounds into oxides via nitric acid leaching and roasting. The influence of pretreatment temperature, nitric acid concentration, amount of nitric acid, and roasting temperature were evaluated. The signal-to-noise ratio and analysis of variance of the results were determined using L₁₆(4⁴) orthogonal arrays. The findings indicated that the roasting temperature followed by the nitric acid concentration, pretreatment temperature, and amount of nitric acid used had the greatest impact on the lithium leaching ratio. Following detailed experiments, the optimal conditions were found to be 10 h of pretreatment at 700℃ with 2 ml/g of 10 M nitric acid leaching followed by 10 h of roasting at 275℃. Under these conditions, the overall recovery of lithium exceeded 80%. X-ray diffraction (XRD) analysis of the leaching residue in deionized water after roasting of lithium nitrate and other nitrate compounds was performed. This was done to determine the cause of rapid decrease in lithium leaching rate above a roasting temperature of 400℃. The results confirmed that lithium manganese oxide was formed from lithium nitrate and manganese nitrate at these temperatures, and that it did not leach in deionized water. XRD analysis was also used to confirm the recovery of pure LiNO₃ from the solution that was leached during the nitration process. This was carried out by evaporating and concentrating the leached solution through solid-liquid separation.

• The Korean Journal of Food And Nutrition
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• v.36 no.6
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• pp.479-488
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• 2023

In this study, quality properties of rapeseed oil by different roasting temperatures (140, 160, 180, and 200℃) were investigated. Roasted-pressed oil (RPO) showed a decrease in lightness and an increase in redness and yellowness with an increase in temperature compared to cold-pressed oil (CPO). In addition, the β-carotene and tocopherol content also increased in RPO as the roasting temperature increased. The tocopherol content increased by 18~20% in RPO at 200℃ compared to CPO. This increase in bioactive components led to improved radical scavenging activity dependent on roasting temperature, and RPO at 200℃ showed a 2.7-fold improvement compared to CPO. Finally, it was observed that higher roasting temperatures resulted in an extended oxidation induction period, increasing by up to 3.3 times. In conclusion, roasting is an effective method for enhancing the oil functionality of domestic rapeseed varieties. This study provides basic data for producing high-quality oil.