• The Korean Journal of Food And Nutrition
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• v.26 no.1
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• pp.51-59
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• 2013

This study aims to understand college students customer's preference and the difference of coffee grade by comparing the result of Q-grader, who was trained professionally and received certification for a sensory evaluation of coffee grade. The results of the chemical analysis of raw coffee and coffee berry show that those of specialty grade had slightly higher, but not significant, water content. Further, the pH of specialty grade coffee was high in coffee beans and after roasting, the commercial grade became high. There was no significant difference between the specialty degree and commercial degree in color before and after roasting. In this study, the panels for the sensory evaluation included 24 university students. The preference of evaluation items of sensory evaluation consist of aroma, acidity, bitterness, astringency, aftertaste, and overall satisfaction. Items for the strength evaluation consist of aroma, acidity and bitterness. The sensory evaluation was expressed by applying a 5 point Likert scale (1: extremely low~5: extremely high). In the sensory evaluation, it was evaluated that specialty grade coffee had strong acidity and commercial grade coffee was strongly bitter. The result of the sensory evaluation shows that female students are sensitive to coffee taste. In the analysis of frequent visit to coffee shop, the not-frequently-use-group rated that specialty grade coffee with higher overall satisfaction than commercial grade coffee in factors such as aroma and acidity. The group which did not prefer Americano coffee rated that specialty grade was higher than commercial grade in all factors except aroma, of which the result is similar to the cupping test.

• Korean journal of food and cookery science
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• v.26 no.3
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• pp.300-306
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• 2010

Arabica coffee has been classified for trading according to the New York Board of Trade (NYBOT) green coffee classification. The aim of the present study is to evaluate the physiochemical and sensorial characteristics of coffees classified by NYBOT as NY2 (specialty coffee), NY3/4 and NY4/5 (commercial coffee). The density of green coffee was higher for the NY2 sample. The amount of total solids in brewed coffee increase as the green coffee grade decreased and the pH levels decreased as the coffee grade decreased. Descriptive analysis using a 15cm line scale was carried out by 12 trained panelists prepared by espresso coffee and consumer preference tests were carried out by 168 consumers. The NY2 sample had the highest fruity, acidity, sweetness and aftertaste characteristics. In addition, green, rio, sour and astringency characteristics increased as the coffee grade decreased. Acceptance of aroma, flavor, taste balance and overall were higher for the NY2 sample. In the consumer preference test, the NY2 and NY4/5 samples had a similar distribution, but consumers between the ages of 20 to 30 who like to drink brewed coffee more than instant coffee preferred the NY2 than sample over the NY3/4 sample. In conclusion, significant differences were observed among the three groups of green coffee classification in all physicochemical and sensory parameters.

• Clean Technology
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• v.27 no.4
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• pp.325-331
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• 2021

In this study, bio-carbons were produced by activation process from unused biomass (Grade 3 wood pellet and spent coffee grounds) to determine the removal performance of formaldehyde and acetaldehyde. The activation experiments were conducted in a fixed bed reactor using CO₂ as an activation agent. The temperature of the activation reactor and input of CO₂ were 900 ℃ and 1 L min^-1 for all the experiments. The maximum BET surface area of about 788 m² g^-1 was obtained for bio-carbon produced from Grade 1 wood pellet, whereas about 544 m² g^-1 was achieved with bio-carbon produced from spent coffee grounds. In all the experiments, the bio-carbons produced were mainly found to have micro-porous nature. A lower ash amount in raw material was favored for the high surface area of bio-carbons. In the removal test of formaldehyde and acetaldehyde, the bio-carbon produced from spent coffee grounds showed excellent adsorption performance compared with woody biomass (Grade 1 wood pellet and Grade 3 wood pellet). In addition, the comparative experiment of commercial impregnated activated carbon and bio-carbon produced from spent coffee grounds was conducted. In terms of formaldehyde removal performance, the commercial impregnated bio-carbon was excellent, while bio-carbon produced from spent coffee grounds was excellent in acetaldehyde removal.

• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1471-1476
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• 1999

A simple and practical method for determination of caffeine in foods was developed. The analysis of caffeine was performed by reverse phase high performance liquid chromatography using a ${\mu}-Bondapak\;C_{18}$ column at isocratic condition with methanol-acetic acid-water(20 : 1 : 79) on UV detector at 280 nm. The clean-up and extraction of caffeine in samples were based on a simple pretreatment using a Sep-Pak $C_{18}$ cartridge. Recovery rates obtained with this method for cider, candy, cookie, milk, ice cream and persimmon leaf tea were 99.23%, 99.50%, 99.17%, 99.37%, 98.93% and 99.10% respectively. And the detection limit of caffeine was $0.1\;{\mu}g/mL$. With this method, the range of caffeine contents extracted from coffee, green tea, black tea, Oolong tea(tea bag), soft drinks, ice cream, milk and commercial confectionery were $3.38{\sim}37.50\;mg/g,\;16.30{\sim}26.10\;mg/g,\;10.80{\sim}16.65\;mg/g,\;11.25\;mg/g,\;0.06{\sim}0.11\;mg/g,\;0.04{\sim}0.44\;mg/g,\;0.04{\sim}0.39\;mg/g\;and\;0.10{\sim}1.80\;mg/g$, respectively. But caffeine was not detected in the other tea such as Acanthopanax sessiliflorum tea, Angelica gigas tea, Angelica tea, Arrow root tea, Duchu'ng tea, Dunggulle tea, Ganoerma lucidum tea, Ginger tea powder, Persimmon leaf tea, Ssanghwa tea and Cocoa mix powder.