• KSBB Journal
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• v.23 no.3
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• pp.193-198
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• 2008

In this study, the supercritical $CO_2$ extraction was applied for the enrichment of coffee flavors. The extraction efficiency of coffee flavors was dependent on the pressure and temperature and optimized as 350 bar and 80$^\circ$C. Five flavors of high aroma values were analyzed. The flavors extracted by the supercritical $CO_2$ extraction were 76.6 times higher than those by the traditional method, espresso extraction. The modified headspace system proved the enhanced efficiency of supercritical $CO_2$ extraction. The coffee beverage containing the extract of supercritical $CO_2$ resulted 2.3 times of flavor enrichment when it was compared to that without the supercritical extract.

• Korean journal of food and cookery science
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• v.27 no.6
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• pp.773-781
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• 2011

Coffee beans are processed from coffee cherries by either natural, pulped natural, or washing. The aim of the present study was to evaluate the physiochemical and sensory characteristics of espresso coffees processed by different methods. The color of the washed coffee sample presented the highest value of lightness while the natural coffee sample presented the highest value of redness and yellowness. The biggest difference in brewed coffee, whether natural, pulped natural, or washed, was in the TDS content, which was higher in natural coffee and lower in washed coffee. Sensory descriptive analysis and acceptance test for espresso coffee using a 15 cm line scale were carried out by 12 trained panelists. Natural coffee had the highest cherry-like flavor and sweetness taste while washed coffee had the highest citrus flavor and acidity taste. An important attribute of espresso coffee is body, and natural coffee presented strong body while washed coffee presented a low body attribute. In conclusion, significant differences were observed among the three processing methods of green coffee. Pulped natural coffees presented intermediate physiochemical and sensory characteristics compared to washed and natural coffee. Natural coffees are appreciated for their increased body, and washed coffees are appreciated for added citrus flavors and acidity espresso coffee blends.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.2
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• pp.255-261
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• 2013

This study investigated changes in the physicochemical characteristics and coffee flavors of coffee beans under different roasting conditions. Four different kinds of roasted coffees were analyzed using a headspace gas chromatographic technique. The moisture content and total acidity of roasted coffee decreased whereas the pH and weight loss (%) increased, as coffee beans were roasted at higher temperatures. The Hunter's color values of the roasted coffee (indicating L (lightness) and b (yellowness)) decreased as the roasting temperature of the coffee beans increased, but a (redness) value only increased with light roasting. We also noted that the color of the Arabica coffee was darker than that of the Robusta coffee. The aroma compounds, acetaldehyde, acetone, 2-methylfuran, 2-methylbutanol, 2-methylpyrazine, furfural, 2-propanone, furfuryl alcohol, 2,5-dimethylpyrazine and furfuryl acetate were mainly analyzed. A sensory evaluation of all light-roasted coffees had flavor and sourness and those of all medium-roasted coffees had heaviness and finishness.

• Journal of the East Asian Society of Dietary Life
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• v.23 no.3
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• pp.382-390
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• 2013

The purpose of this study is to provide the basic findings concerning a quality evaluation. The first conclusion is the coffee's $CO_2$ gas production between a roast brewed at 0 hour and 72 hours after grinding. The espresso, 48 hours after its grind, emits a small amount of $CO_2$ gas, whereas 72 hours after being grinded there is no discharge. In the sensory evaluation, the overall preference is the 72 hours later grind, in accordance to the decrease of the bitter, acid, and sour taste with the increase of the sweet, nutty, and chocolaty flavors. The foam index indicates a significant reduction between the roasts brewed at 0 hour and 72 hours after grinding. A persistence of crema in the Colombian Colombia and Ethiopian Yirgacheffe decline for the 72 hours after its grind coffee. The Tanzanian Kilimanjaro and Brazilian Cerrado roasts show no difference. The pH is decreased in the 72 hours after its grind roast. Moreover, sugar contents in the Colombian Excelso and Brazilian Cerrado are increased, whereas the Tanzanian Kilimanjaro sugar contents are decreased, along with its density.

• Korean Journal of Food Science and Technology
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• v.43 no.3
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• pp.348-360
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• 2011

To verify the volatile compounds contributing to coffee off-flavor, medium roasted Colombian, Sumatra, Ethiopian and light and dark roasted Colombian bean coffees were sequentially and studiously over extracted. Eight espresso samples and eight filter-dripped samples were analyzed by gas chromatography/mass spectrometry with the solidphase microextraction method and evaluated by sensory tests. In total, 67 compounds were detected, and desirable aroma decreased sharply, while off-flavors increased rapidly after 30 mL of espresso and 200 mL of drip coffee. Percent peak area of 4-ethylguaiacol revealed a linear increase during extraction and was highly correlated with increasing off-flavor, suggesting that it could be an indicator of over extraction. Considering the odor activity value, guaiacol and 4- vinylguaiacol were also contributory compounds to off-flavors.

• Journal of the Korean Society of Food Culture
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• v.27 no.5
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• pp.512-520
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• 2012

This study investigated the sensory characteristics of adlay tea favorably consumed by Korean consumers and analyzed the drivers behind for liking or disliking adlay tea. Six adlay tea products showing the highest market share in South Korea were selected. Sensory properties of the six products were analyzed using generic descriptive analysis. Among these, four products were further selected for consumer taste acceptance test. Sensory lexicons of adlay tea were developed by trained panelists, and the sensory characteristics of each adlay tea product were measured based on the perceived intensities of these attributes elicited from the samples. In the consumer taste acceptance test, frequent tea and coffee drinkers participated. Consumers rated the acceptance of each tea product on a 9-point hedonic scale and evaluated the reasons for liking or disliking each product based on the check-all-that-apply method. Analysis of Variance, principal component analysis, frequency analysis, and correspondence analysis were utilized for statistical analysis. Twenty sensory attributes were developed in order to characterize the six adlay tea products. The results of the descriptive analysis showed that attributes such as viscosity, black soybean flavor, goso flavor, peanut flavor, seaweed flavor, green, and presence of chunks were key factors differentiating the adlay tea products. In the consumer taste test, roasted flavor, goso flavor, peanut flavor, and presence of chunks were positive drivers for liking the adlay tea products, whereas seaweed and green flavors were negative attributes that drove consumers away.