• Korean Journal of Food Science and Technology
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• v.32 no.3
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• pp.654-658
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• 2000

Flavor components focused on the methyl pyrazines(2,3-dimethyl pyrazine, 2,3,5-trimethyl pyrazine, tetramethyl pyrazine) of microwave-roasted cocoa beans were determined and compared with those of conventionally-roasted cocoa beans. Domestic microwave oven was modified to design the microwave roasting system. Temperature measurement technique using thermocouple probes was developed to determine the center temperature of cocoa beans during microwave roasting. Microwave roasting was carried out under two different conditions. Under the first condition, roasting time was fixed to 30 min, while roasting temperature was varied to $110^{\circ}C,\;120^{\circ}C,\;130^{\circ}C,\;140^{\circ}C,\;and\;150^{\circ}C$ Under the second condition, roasting temperature was fixed to $130^{\circ}C$, while roasting time was varied to 5 min, 10 min, 20 min, and 30 min. Conventional roasting was done at $120^{\circ}C$ for 15 min as a reference. Amount of methyl pyrazines and their ratios were influenced by microwave roasting temperature and roasting time. The most suitable methyl pyrazine ratio of cocoa beans was obtained at $140^{\circ}C$ for 30 min of microwave roasting.

• Korean Journal of Food Science and Technology
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• v.32 no.4
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• pp.814-821
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• 2000

The physicochemical properties of microwave-roasted cocoa beans such as color, degree of browning, pH, titrable acidity, organic acid, and sugar content were determined and compared with those of conventionally-roasted beans. Microwave roasting temperatures were 110, 120, 130, 140 and $150^{\circ}C$. Roasting times were 0, 5, 10, 20, and 30 min. Conventional roasting was done at $120^{\circ}C$ and 15 min as a reference. The pH had no relations with roasting temperature or roasting time. As roasting time and roasting temperature were increased, the titrable acidity values of roasted cocoa beans became higher than those of raw bean. But there were no differences among each condition. Color, degree of browning, and sugar content changed as roasting temperature and roasting time increased. The organic acid content of roasted beans increased but the degree of increase was different from organic acid to organic acid. Roasting by microwaves resulted in higher inner temperature of samples than the surface temperature. To increase roasting efficiency, the other heat sources should be used together with microwave.

• The Korean Journal of Food And Nutrition
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• v.26 no.3
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• pp.502-507
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• 2013

This study was investigated the optimal time that enhanced the functional activities of mung beans for use of functional food resources. Mung beans were roasted according three levels of roasting time levels (10, 20 and 30 minutes) at $110^{\circ}C$ and then the physicochemical compositions were determined. The reducing sugar content was decreased with the increased roasting time. Moisture was decreased with increased roasting time, whereas, crude fat, crude ash, crude protein and carbohydrate were increased with prolonged roasting time. The highest contents of total phenol and flavonoid were shown at a roasting condition $110^{\circ}C$ for 30 minutes. The highest inhibitory activities of DPPH radical, ABTS radical and xanthine oxidase was the best at the condition of $110^{\circ}C$ for 30 min. From these results optimal roasting time of mung beans were 30 minutes for use of functional food resources.

• The Korean Journal of Food And Nutrition
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• v.12 no.5
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• pp.484-489
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• 1999

Rosting conditions for improvement of viscosity and sensory properties of sea tangle extracts were investigated. The supernatant % solid yield and crude protein yield were increased by increasing of roasting temperature and times. The highest contents of algin was obtained in roasting temperature of 175$^{\circ}C$ ash contents were increased by roasting temperature increasing. Viscosities of sea tangle extract were significantly decreased by increasing of roasting temperature and time upto 175$^{\circ}C$ and 10 mins more than further roasting conditions. The pH of sea tangle extracts slightly decreased from 5.94 to 5.83 in the roasting of 15$0^{\circ}C$ however at temperature more than 175$^{\circ}C$ its pH was increased by increasing of temperature and time. According to increase of roasting temperature and time Lightness (L value) were significantly decreased and redness (a value) and yellowness (b value) reached the highest value in the roasting of 20$0^{\circ}C$ 15 min. or 175$^{\circ}C$ 30 min and after that its value were decreased. The odor characteristics showed that sea tangle extract prepared by roasting of 175$^{\circ}C$ 10mins was slightly reduced in intensity of savory and seaweed taste but significantly low in intensity of nauseous taste and high in intensity of roasted taste and accetability. Overall data suggested 175$^{\circ}C$ 10min was the most effective roasting conditions for improvement of viscosity and sensory properties of sea tangle extract.

• Korean journal of food and cookery science
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• v.25 no.4
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• pp.496-505
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• 2009

The influence of roasting time on antibacterial and antioxidative effects of methanol and water coffee extracts was investigated. Extract yield differed with roasting time. The maximum yield of methanol extract was 20.02% and 24.00% at respective roasting times of 12 and 20 min. The maximum yield of water extracts was 2.70% and 18.58% at 5 and 25 min roasting time, respectively. Antibacterial effects of each extract were determined by the classical minimal inhibitory concentration (MIC) paper disc diffusion method. Methanol extracts of different coffee samples inhibited growth of various strains except Escherichia coli. Extracts obtained following roasting times of 12, 14, 16, 20, and 25 min in particular displayed the most potent activity against Staphylococcus aureus. Among these extracts, that obtained from 12 min roasted coffee samples produced a MIC of $16.125{\mu}g$/mL against S. aureus. Water extracts applied at $1,000{\mu}g$/mL were growth inhibitory except against Salmonella choleraesuis and Prevotella intermedia. However, growth inhibition by water extracts was weak, with inhibitory zones of only 6-8 mm diameter produced. Determinations of free radical elimination for the different coffee extracts using 1,1-diphenyl-2-picrylhydrazyl were compared with ascorbic acid and butylated hydroxytoluene positive controls. Methanol and water extracts of different coffee samples ($100{\mu}g$/mL) showed $67.1{\sim}92.3%$ and $66.4{\sim}93.3%$ radical scavenging activity, respectively. However, longer roasting time (especially >20 min) tended to somewhat lower free radical elimination using both extracts. Total phenol in different coffee samples measured by the Folin-Denis method revealed the highest level of phenol contents with non-roasted coffee, whereas phenol content differed with different roasting time, ranging from $87.{\sim}126.5\;mg/g$ in methanol extracts. In water extracts, the phenol content was maximum at 8 min roasting time, whereas in other samples the content was varied from $95.0{\sim}199.1\;mg/g$.

• Food Science and Preservation
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• v.12 no.2
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• pp.166-172
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• 2005

Response surface methodology (RSM) was applied to monitor the effects of steaming and roasting conditions of Polygonatum odoratum roots an total phenolics content, electron donating ability (EDA) and nitrite-scavenging ability (NSA) of the extract. In steaming and roasting processes based on the central composite design. with variations in steaming time $(60\~180\;min)$, roasting temperature $(110\~150\;min)$ and roasting time $(10\~50\;min)$, coefficients of determinations $(R^2)$ were 0.9356 (p<0.01) in total phenolics, 0.9578 (p<0.01) in EDA and 0.9436 (p<0.01) in NSA (pH 3.0). The maximum value of total phenolics was $2847.67\;mg\%$ at 135.59 min of steaming time, $143.84^{\circ}C$ of roasting temperature and 43.47 min of roasting time. The maximum value of EDA was $75.00\%$ in 108.98 min, $135.56^{\circ}C$ and 48.86 min. The maximum value of NSA (pH 3.0) was $87.38\%$ in 162.80 min, $143.88^{\circ}C$ and 31.97 min, respectively. Total phenolics content of the extract was influenced by heating conditions in the order of roasting temperature, steaming time and roasting time. While EDA and NSA were appreciably influenced by roasting time, followed by roasting temperature and steaming time.

• Culinary science and hospitality research
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• v.23 no.5
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• pp.1-11
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• 2017

The objectives of this study were: 1) to examine the contents of chemical composition (chlorogenic acids, caffeine, free acids, and free sugars) and 2) to evaluate the sensory attributes (sourness, bitterness, and sweetness) of brewed coffee as affected by two roasting conditions such as varied in the roasting time with the same roasting temperature (RT) and with same color and yield (CY). Quantitative analysis of chemical components was performed using high-performance liquid chromatography (HPLC) system, and quantitative descriptive analysis (QDA) was conducted to analyze sensory attributes. Based on the results of chemical analysis, chlorogenic acids were significantly different (p<0.05) in the short term roasted samples (RT 240 and CY 240), but there was no significant difference in caffeine contents (p>0.05). Organic acid levels were different between RT and CY coffee samples. RT 240 coffee had the most level in organic acids and the longer the roasting time of coffee, the lesser the level of organic acids in coffee was found. However, there was no significant difference in CY coffee (p>0.05). The results of sensory evaluations show that the degree of roasting changed according to the roasting time despite of the roasting temperature. Long term (RT 80) coffee was relatively bitter while short term (RT 240) coffee was relatively sweeter. Also, there was no significant difference (p>0.05) in the sensory characteristics (bitterness and sweetness) of CY coffee although they were roasted at different temperatures. Therefore, the current study concluded that better understanding of proper roasting time and temperature improves the quality of brewed coffee.

• Journal of the East Asian Society of Dietary Life
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• v.16 no.5
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• pp.573-577
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• 2006

The rutin content of Fagopyrum tataricum is 100-fold higher than that of Fagopyrum esculentum. For the development of a rutin-containing beverage, a suitable method to extract rutin from buckwheat (Fagopyrum tataricum) with high rutin yield was investigated. A roasting temperature range of $310/240^{\circ}C$ (Ed-confirm that this is indeed a range; otherwise perhaps, 'Roasting temperatures ranging from 310 to $240^{\circ}C$ were considered$\ldots$') was considered to be the best as the basic color reference. Rutin content varied according to the roasting time and heating temperature; i.e., it decreased with increasing roasting time and temperature. (Ed- this sentence is unnecessarily complicated and should be simplified to 'Rutin content decreased with increasing roasting time and heating temperature.') The optimal extraction temperature and processing time were obtained as $80^{\circ}C$ and 10 minutes to maximize the rutin concentration in the extract.

• Food Science and Preservation
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• v.15 no.3
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• pp.396-404
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• 2008

This study investigated the functional properties of lateral roots of red ginseng following roasting treatment The ten different conditions, based on the central composite design for roasting parameters, were pre-established according to roasting temperature($140{\sim}240^{\circ}C$) and time($5{\sim}25\;min$). The functional characteristics were monitored using response surface methodology, whereby polynomial equations and correlation coefficients were investigated between roasting conditions. The functional properties of the samples were affected more by roasting time than temperature. The optimal roasting condition ranges for maximizing the functional qualities of lateral roots of red ginseng were predicted to be a roasting temperature of $194.5-210.9^{\circ}C$, and a roasting time of 13.8-20.0 min.

• 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.