• Applied Biological Chemistry
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• 제39권5호
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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.

• Resources Recycling
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• 제18권5호
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• pp.19-25
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• 2009

Molybdenite concentrate ($MoS_2$) is the major mineral for the molybdenum industry, of which the industrial processing is first converted to technical grade molybdenum trioxide ($MoO_3$) by its oxidative roasting and purification, used as a raw material for manufacturing several molybdenum compounds. In the present work, detailed experimental results for the oxidative roasting of low grade Mongolian molybdenite concentrate are presented. The experiments were carried out in the temperature range of 793 to 823 K under an oxygen partial pressure range of 0.08 atm to 0.21 atm by using a thermogravimetric analysis technique. The molybdenite concentrate was an average particle size of $67\;{\mu}m$. In the oxidative roasting of low grade Mongolian molybdenite concentrate, more than 95% of molybdenite was converted to molybdenum trioxide in 60 min. at 828 K. The lander equation was found to be useful in describing the rates of the oxidative roasting and the reaction order with respect to oxygen concentration in a gaseous mixture with nitrogen was 0.11 order.

• Journal of the Korean Society of Food Science and Nutrition
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• 제39권11호
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• pp.1715-1718
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• 2010

The oxidative stability of grape seed oils (GSOs) prepared from grape seeds roasted at different temperatures (100, 150 and $200^{\circ}C$ for 1 hr) was evaluated and compared with that of GSO from unroasted grape seed. Stability of the GSOs stored in air at $50^{\circ}C$ up to 40 days was assessed by acid value (AV) and peroxide value (PV). Simultaneously, the cont ents of tocopherols and tocotrienols and color changes were monitored up to 40 days. During the storage period, the PV of the unroasted GSO increased from 1.95 to 90.72 meq/kg. On the other hand, the PV for GSOs roasted at 100, 150 and $200^{\circ}C$ increased from 1.96, 2.03, 1.98 to 76.09, 71.72, 49.38 meq/kg, respectively. AV is in conformity with PV. Color development of GSOs increased as roasting temperature increased. The contents of tocopherols and tocotrienols in GSOs increased as roasting temperature increased from 100 to $200^{\circ}C$. The contents of tocopherols and tocotrienols gradually decreased along with the storage period. These results suggest that roasting treatment prolongs the oxidative stability of GSOs.

• Korean Journal of Food Science and Technology
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• 제32권2호
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• pp.246-251
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• 2000

This study was investigated to compare the changes of antioxidative compounds in sesame oil with roasting temperature$(110^{\circ}C{\sim}230^{\circ}C)$. Lightness was decreased markedly over $170^{\circ}C$. In the changes of lignan contents, 7 different lignans unchanged up to $170^{\circ}C$ and sesamolin and sesamin decreased markedly, whereas sesamol, unknown1, unknown3 increased drastically at the higher temperatures. In tocopherol contents, ${\gamma}-tocopherol$ decreased from 70.59 mg% in unroasted oil to 33.87 mg% at $220^{\circ}C$, and to 26.73 mg% at $230^{\circ}C$. In the result of AOM(active oxygen method) test carried out at $120^{\circ}C$ for evaluating oxidative stability, the induction period of unroasted oil was 4.12 hrs and that of roasted oils was increased with roasting temperature (induction period at $220^{\circ}C$ was 27.9 hrs.). From the above results, it was confirmed that correlation coefficient between oxidative stability and lightness is -0.993 and that between oxidative stability and sesamol content is 0.934 above $170^{\circ}C$. Therefore its remarkable oxidative stability with the roasting temperature, might be considered to be due to the increase of sesamol, other lignans(unknown 1, unknown 3).

• Journal of the Korean Society of Food Culture
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• 제36권3호
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• pp.308-316
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• 2021

The present study aimed to evaluate the effects of roasting temperature on the quality characteristics and biological activity of quinoa. Quinoa was roasted at 160, 200, and 220℃ for 20 min. The lightness (L^*) of quinoa decreased, however, the redness (a^*) increased as the roasting temperature increased. The yellowness (b^*) was the highest at 160℃ and decreased at 200 and 220℃. The highest contents of total polyphenol, flavonoid, and quercetin were observed at 220℃, the highest roasting temperature. The highest radical scavenging activities of 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (73.65%) and α,α-diphenyl-β-picrylhydrazyl free radicals (47.82%) were found in roasted quinoa at 220℃. The α-glucosidase activity was inhibited by 62.13% at this temperature. The roasted quinoa at 220℃ also showed a significant cytoprotective effect against oxidative stress in HepG2 cells. These results could be useful in the development of food products using quinoa.

• Journal of Life Science
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• 제16권3호
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• pp.427-432
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• 2006

The possibility of citron seed oil for use as food resources of fats was tested by analyzing the composition of fatty acid and oxidative stability. Oil yield from citron seed was 55.4% in without roasting and 56.8% with roasting. Total mineral content in citron seed without and with roasting were 2,820.33 mg/kg, 1,702.55 mg/kg, respectively. For all citron seed oils tested, the potassium content was found to be the highest among four kinds of minerals detected in this study. Further, major fatty acids detected in the citron seed oils were linoleic acid, oleic acid and palmitic acid. Their relative contents with respect to total fatty acid contents were 77.12% in without roasting and 67.67% in with roasting. This result indicated that roasting the citron seed decreased the acid contents. However, POV (peroxide value) and acid value of citron seed oils were in,.eased significantly with increasing the storage days and heating time. In details, POV was $84.17{\pm}1.68meq/kg$ in without roasting and $76.46{\pm}1.19meq/kg$ with roasting, after 28 days. Acid value was $9.52{\pm}0.27mg\;KOH/g,\;8.35{\pm}0.09mg\;KOH/g$, respectively, After the 48 hours heating at $180^{\circ}C$, POV of citron seed oils was increased by 3.8 times, irrespective of roasting. Yet, acid value increased dramatically 8.3 in without and 6.4 times with roasting, exhibiting its dependence on roasting. During storage time, oxidative stability of citron seed oils was higher than heating.

• Korean Journal of Human Ecology
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• 제23권2호
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• pp.357-366
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• 2014

In this study, we manufactured mung bean Dasik (pattern pressed candy) after selecting the optimum roasting conditions through physiochemical analysis and sensory evaluation. Then anti-oxidative abilities of roasted mung bean were measured in order to develop beauty food (Dasik) using roasted mung bean. In the content of vitexin and isovitexin of roasted mung bean, about 10 times the vitexin in the seed(60.85 mg/g) is found in the skin of raw mung bean, and about 9 times the isovitexin in the seed(71.42 mg/g) is also found in the peel. As a result of analyzing the seed and peel of mung bean after roasting it for 10, 20 and 30 minutes respectively, the optimum roasting condition is thought to be $110^{\circ}C$ for 30 minutes as the contents of vitexin and isovitexin showed the highest values of 104.94 mg/g and 122.02 mg/g respectively when the mung bean was roasted at $110^{\circ}C$ for 30 minutes. In the anti-oxidative activity evaluation of the optimum mung bean Dasik, the total content of phenol was shown to be 0.15 mg/mL, and the total content of flavonoid was shown to be 0.026 mg/mL. The DPPH radical scavenging ability showed a high vitality of 58.19%, and the ABTS radical scavenging ability was shown to be 13.26%.

• Journal of Applied Biological Chemistry
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• 제60권4호
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• pp.383-390
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• 2017

Regarding the facts that fat, which is easily oxidized, is one of the major responsible factors affecting the quality of aroma, and polyphenol compounds including chlorogenic acid (CGA) contribute the anti-oxidative activities to coffee, we investigated fat oxidation, conversion of CGA, and changes of anti-oxidative activities according to the degree of roasting and storage of 60 days. We found that the amount of extractable fat by diethyl ether is increased as the coffee beans are roasted longer. Furthermore, the acidity values of the fat are increased from $8.91{\pm}0.16$ to $17.81{\pm}0.11$, and $10.37{\pm}0.27$ to $17.93{\pm}0.09$ in the medium and dark roasted coffee beans, respectively, while it is increased from $4.47{\pm}0.11$ to $11.89{\pm}0.18$ in the green coffee bean after 60 days. The CGA contents in the coffee beans were decreased from $310{\pm}8.2$ to $282{\pm}11.2$, then to $58{\pm}0.0mg$ in 10 gr of the green, medium and dark beans, respectively, and were not changed significantly during the storage period. However, the anti-oxidative activities measured by 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid radical scavenging assays were not significantly different among the green, medium, and dark coffee beans during the storage period. Furthermore, antioxidant reactive element-luciferase assay showed that biological anti-oxidative activities were increased as coffee beans were more roasted and stored longer. As the total polyphenolic contents in the beans were significantly decreased by roasting, the results suggests that other molecules, such as, Maillard reaction products might play substantial role in anti-oxidative activity and influence cup quality of coffee.

• Korean Journal of Food Science and Technology
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• 제35권3호
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• pp.347-352
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• 2003

In order to compare quality characteristics and oxidative stabilities of rice germs prepared under different roasting conditions, sensory evaluation, color value, tocols (tocopherol+tocotrienol) contents, and peroxide value were investigated. Optimum roasting temperatures for the best acceptability were 20, 10, and 6 min at 170, 180 and 190, respectively. Hunter color a values of rice germ increased as roasting temperature and time increased, whereas L value decreased. Peroxide values of unroasted, and roasted rice germs at $170^{\circ}C$ for 20 min, $180^{\circ}C$ for 10 min, and $190^{\circ}C$ for 6 min were 2.0, and 145.6, 169.5, and 182.9 meq/kg, respectively, after 9 days storage at $60^{\circ}C$. Four tocopherol and three tocotrienol isomers were identified, whereas no ${\beta}$-tocotrienol was detected. The major tocopherol and tocotrienol isomers in rice germ were ${\alpha}$-tocopherol and ${\alpha}$-tocotrienol, respectively. ${\alpha}$-Tocopherol content in roasted rice germ decreased significantly during storage, whereas those of ${\beta}$- and ${\gamma}$-tocopherols slowly decreased. ${\delta}$-Tocopherol had the highest stability among tocopherol isomers in roasted rice germ. Similar trends were observed in tocotrienol isomers.

• Korean Journal of Medicinal Crop Science
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• 제8권3호
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• pp.194-200
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• 2000

The main objective of this study was to characterize physico-chemical properties, sensory property and oxidative stability of safflower seed obtained by various roasting temperature and time. The contents of water soluble solids decreased in the higher roasting temperature and time. Sensory evaluation of safflower seed roasted in various conditions showed significant differences in taste, color, flavor and palatability. The safflower seed roasted at $190^{\circ}C$ for 20min had the best palatability. At the change of Hunter's values, L values were decreased, and a, b and ${\Delta}E$ values were increased in the higher roasting temperature and time. The content of free sugars such as sucrose and raffinose were reduced significantly in higher roasting time of $190^{\circ}C$ and $210^{\circ}C$. During the storage period after roasting treatment, peroxide values (POV) were highly increased after eight months at the all treatment except for $150^{\circ}C$. Therefore, it is inadequate over eight months after roasting treatment.