• Korean Journal of Food Science and Technology
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• v.33 no.3
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• pp.333-337
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• 2001

The effect of roasting of Omija (Schizandra chinensis Baillon) on the physicochemical properties and the sensory quality of the extract was investigated in order to improve the quality of Omija beverage. The response surface methodology was introduced to optimize the roasting condition of Omija based on the sensory quality of the extract. The titratable acidity, the soluble solid content and the reducing sugar content of the extract increased with a mild roasting, but decreased with an excessive roasting. Prolonged roasting at high temperature decomposed red pigment making the color of the extract lighter, less red and less yellow. A mild roasting of Omija improved the sensory quality of the extract, and the highest sensory quality of the extract was provided with the roasting at $180^{\circ}C$ for 10 min, indicating the optimum roasting condition of Omija. The extract of the roasted Omija was superior in sensory properties to that of the unroasted one.

• Food Science and Preservation
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• v.23 no.5
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• pp.673-679
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• 2016

This study was performed to verify the possibility of manufacturing a germinated aromatic rice tea, which was roasted at 200, 250, and $300^{\circ}C$ each for 10, 20, and 30 min. The roasted aromatic rice was analysed physicochemical properties, sensory characteristics and aromatic compounds. The total polyphenol content and DPPH radical scavenging activities of the germinated aromatic rice increased as the roasting temperature and time increased. Total soluble solid contents, turbidity and browning index of the germinated aromatic rice tea also increased was the roasting temperature and roasting time increased. The pH did not change by roasting. The main aromatic components in roasted germinated aromatic rice tea were 2-methyl butanal, 3-methyl butanal, benzaldehyde and nonanal, which increased according to increasing temperature and time. However, those favorable aroma components were decreased at more than $300^{\circ}C$ of roasting temperature. In addition, methyl benzene, pentanol were increased which affect odor aroma. The sensory score of germinated aromatic rice tea also increased with high roasting temperature and time. However, aromatic rice roasted at a higher temperature ($300^{\circ}C$) showed lower sensory score. Therefore roasting temperature and time must be controlled for manufactureing high quality of germinated aromatic rice tea, and the optimun roasting conditions were $250^{\circ}C$ and 30 min, which provide best physicochemical characteristics of aromatic rice tea.

• The Korean Journal of Food And Nutrition
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• v.33 no.5
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• pp.570-575
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• 2020

In this study, to develop balloon flower (Platycodon grandiflorum) leaves, which are not used as tea, a method of making green tea was referred to, and several physiological activities were analyzed using the balloon flower leaf tea with different times of roasting and rubbing. The highest total polyphenol and tannin contents were 33.02 mg GAE/g and 5.03 mg/g at two times of roasting and one time of rubbing, respectively. In the case of the total flavonoids, the RO3 + RU2, subjected to three times of roasting and two times of rubbing, showed the highest value, whereas there was no significant difference between the control and the other samples. Except for the green tea as a control, the RO2 + RU1 samples reported the highest antioxidant activity whereas it decreased with increasing number of times of roasting and rubbing. The color, lightness, and yellowness tended to decrease slightly as the number of increasing roasting and rubbing among the samples with no significant difference. All of these things together, to develop tea using the balloon flower leaves would be suitable with two times of roasting and one time of rubbing.

• Korean Journal of Food Science and Technology
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• v.28 no.2
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• pp.246-252
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• 1996

Changes in physicochemical properties of the defatted sesame meals at various roasting temperature and time have been studied. The roasting temperatures were $190^{\circ}C,\;210^{\circ}C,\;and\;230^{\circ}C,$ whereas roasting times were 5, 10, 20 and 30 minutes, The protein content of defatted sesame meals decreased during roasting and the oil content of the meals roasted at$210^{\circ}C$ for 10 minutes was 8.4%. The yields of sesame mea]s and oil, when roasted at $210^{\circ}C$ for 10 minutes, were 50.1% and 46.9%, respectively. The amino acids in sesame meals gradually decreased as roasting conditions became severe. Sucrose (162.6 mg%), glucose (37.7 mg%) and fructose (18.7 mg%) were detected in the raw sesame meals. The color of roasted sesame seeds and oils extracted from them became darker as the roasting temperature and time increased and the change in lightness greatly affected the total color change. The browning pigment of the sesame meal roasted at $190^{\circ}C$ was separated into a fraction I, II and III. When roasted at $230^{\circ}C$ for longer than 10 minutes, the soluble browning pigment decreased.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.4
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• pp.591-595
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• 1998

Browning chracteristics were investigated for Chicory roots(Cichorium intybus L.) when roasted at different conditions of 120 to $180^{\circ}C$ in temperature and 10 to 40min in time. The soluble solid of water extracts obtained from roasted Chicory roots increased slowly with increasing roasting temperature and time, but it decreased above $160^{\circ}C$. The contents of reducing sugar and amino-type nitrogen in aqueous extracts obtained from roasted Chicory roots decreased rapidly with increasing the roasting time and temperature. Browning color intensity in aqueous extracts of roasted Chicory roots increased with increasing the roasting temperature and time, Hunter's color L and b values of Chicory powder decreased with increasing the roasting temperature and time, while Hunter's color a and ${\Delta}E$ values continuously increased with increasing the roasting temperature and time.

• Korean Journal of Food Science and Technology
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• v.13 no.4
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• pp.334-339
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• 1981

Surface color, water extract color and soluble solids of the roasted barley resulted from the various roasting conditions were determined to establish the optimum roasting conditions. The correlation coefficients between the surface color of the roasted barley and its ground was in the range from 0.957 to 0.994, and which showed the internal color being well represented that of surface of the roasted grain. The degree of roasting was determined maim by the roasting temperature, rather than by the total heat energy input during roasting. The maximum yield of the water soluble solids was 68% and obtained from the barley roasted at $232^{\circ}C$ for 25 minutes. The readings of Y-value of the roasted whole barley was a good index to judge and control the degree of roasting.

• Applied Biological Chemistry
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• v.39 no.5
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• pp.374-378
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• 1996

The oxidative stabilities of perilla oil increased as roasting temperature and time increased. Induction period of the perilla oil from unroasted perilla seed was 3.9 days, but that of the oil from perilla seed roasted at $210^{\circ}C$ for 30 min was 55 days. The electron donating ability(EDA) on DPPH by perilla oils increased as the roasting temperature and time increased. EDA of the unroasted perilla oil was 24% but that of the perilla oil roasted at $210^{\circ}C$ for 30 min was 64%. These results indicated that the reducing compounds were formed during the roasting process. The fluorescence intensity in perilla oil increased as the roasting temperature and time were increased. This result indicated that Maillard reaction has occurred during the roasting process and the reaction products seemed to provide stability to perilla oil.

• Food Science and Preservation
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• v.22 no.2
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• pp.182-189
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• 2015

Four different kinds of coffee beans (CS, Colombia supremo; EY, Ethiopia yirgacheffee; IM, Indonesia mandheling; and IMM, India monsooned malabar) were roasted at 200 and $250^{\circ}C$ for 10, 15, and 20 min. To determine the optimum roasting conditions, various components of the coffee beans such as pyrazines produced during the roasting, and their antioxidant and antidiabetic effects were analyzed. The different roasting condition did not affect on the concentration of caffeine. However, the amount of 5-caffeoylquinic acid and the total phenolics decreased significantly, at a greater temperature and a longer roasting time. The greatest amount of pyrazines was produced from the IMM however, the amount of pyrazines decreased rapidly at $250^{\circ}C$ according to increasing in roasting time. The DPPH free radical scavenging activity was mostly 80% more effective than that of BHT and ${\alpha}$-tocopherol activities at the same concentration. In the case of the FRAP assay, the reducing power of the coffee slightly decreased at a greater temperature pand longer time. While the inhibitory effect on ${\alpha}$-glucosidase was negligible, the activity decreased by more than 80% when the coffee beans were roasted at $250^{\circ}C$ for 20 min. The inhibitory effect on ${\alpha}$-amylase showed similar results. Taken together, the optimum roasting conditions were determined to be $200^{\circ}C$ and 15 min, which provided the best physiological activity and nutty and chocolatey aromas from the pyrazine of coffee.

• Korean Journal of Food Science and Technology
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• v.39 no.5
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• pp.515-520
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• 2007

To establish the roasting conditions of dandelion leaves for the manufacture of processed foods such as beverages and tea, we investigated the physicochemical and sensory characteristics of dandelion leaves and their hot water extracts by roasting treatment. As the number of roasting times increased, the free sugar content of the roasted dandelion leaves decreased, and in particular, free amino acid and total polyphenol content decreased greatly after only 1 roasting treatment. The amino nitrogen and total polyphenol contents of the roasted dandelion leaf hot water extracts also decreased greatly, and their L-, a-, and b-values showed much lower values than those of the raw leaf extracts. However, a greater amount of reducing sugars was extracted in the roasted leaves than in the raw leaves, suggesting that the roasting process allows for easier extraction of the compounds in dandelion leaves. Five sensory characteristics, including astringent taste, bitter taste, peen flavor, burnt taste, and sweet odor, were deduced through quantitative descriptive analysis of the hot water extracts. Among them, astringent taste, bitter taste, and green flavor showed significant differences between roasting treatments. The sensory evaluation results show that as the number of roasting times increased, the palatability of the hot water extracts increased greatly, in terms of color and taste.

• Journal of the Mineralogical Society of Korea
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• v.26 no.1
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• pp.45-54
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• 2013

In order to dissolve Au, Ag, and other valuable metals from gold ore concentrate, raw gold concentrate was pre-treated by roasting and salt-roasting at $750^{\circ}C$. The roasted concentrate was treated with aqua regia digestion to dissolve the valuable metals and higher amount of Au, Ag, and valuable metals were extracted from the roasted concentrates than from the raw concentrate. Higher amount of these metals were also extracted from the salt-roasted concentrate than from the roasted concentrate. The results of the gold dissolution experiments showed that the gold dissolution was most efficient when particle size, roasting temperature, and the percentage of added salt in salt roasting were about $181{\sim}127{\mu}m$, $750^{\circ}C$, and was 20.0%, respectively. The XRD analysis suggests that quartz and pyrite were not destroyed even through roasting at $750^{\circ}C$ and decomposition with aqua regia. However, through salt roasting, pyrite was completely decomposed, whereas quartz could not be destroyed through salt-roasting at $750^{\circ}C$ and aqua regia digestion. Accordingly, it was expected that the gold contained in quartz can not be dissolved through salt-roasting and treatment with aqua regia.