Analysis of Volatile Compounds in Coffee Prepared by Various Brewing and Roasting Methods

Volatile compounds of coffee brewed under various roasting conditions and by different brewing methods were analyzed. Green coffee beans (Coffea arabica) were roasted at 235 °C for 13 min, 240 °C for 15 min, and 245 °C for 17 min. Roasted coffee beans were ground into particles of three different sizes (710, 500, and 355 μm) and brewed by an espresso coffee machine and the cold brew method. Three types of water (filtered, tap, and bottled) were used for coffee extraction. SPME-GC-MS results indicated that increasing the roasting temperature and time increased the levels of 2,2′-methylene-bis-furan, guaiacol, and 4-ethylguaiacol (p < 0.05) and decreased the levels of furfural (p < 0.05). Grind size was inversely proportional to the measured signal of volatiles by GC-MS (p < 0.05). The measured GC/MS intensities of 2-methylpyrazine, 2,5-dimethylpyrazine, and 2-methoxy-4-vinylphenol were significantly higher in coffee brewed with filtered water (p < 0.05) than tap and bottled water. 2-Methylpyrazine, 1-methylpyrrole, and 2-acetylfuran were the most abundant components in the cold brew. Overall, roasting conditions and extraction methods were determined to be significant factors for volatile compounds in coffee. This is the first study showing the analysis of volatile compounds in coffee according to various types of water and extraction methods, such as espresso and cold brew coffee.

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Comparison of the Antioxidant Activities and Volatile Compounds of Coffee Beans Obtained Using Digestive Bio-Processing (Elephant Dung Coffee) and Commonly Known Processing Methods

Antioxidants ◽

10.3390/antiox9050408 ◽

2020 ◽

Vol 9 (5) ◽

pp. 408

Author(s):

Mesfin Haile ◽

Hyung Min Bae ◽

Won Hee Kang

Keyword(s):

Antioxidant Activity ◽

Volatile Compounds ◽

Green Coffee ◽

Roasted Coffee ◽

Green Beans ◽

Processing Methods ◽

Green Coffee Beans ◽

Coffee Beans ◽

Roasted Coffee Beans ◽

Elephant Dung

There are different types of coffee processing methods. The wet (WP) and dry processing (DP) methods are widely practiced in different parts of coffee-growing countries. There is also a digestive bioprocessing method in which the most expensive coffee is produced. The elephant dung coffee is produced using the digestive bioprocessing method. In the present experiment, the antioxidant activity and volatile compounds of coffee that have been processed using different methods were compared. The antioxidant activity, total phenolic content (TPC), total flavonoid content (TFC), and total tannin content (TTC) of green coffee beans from all treatments were higher as compared to roasted coffee beans. Regarding the green coffee beans, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of elephant dung coffee beans was higher as compared to that of the DP and WP coffee beans. The green coffee beans had higher DPPH activity and ferric reducing antioxidant power (FRAP) value compared to the roasted coffee beans. The green beans of elephant dung coffee had a high TPC than the beans obtained by WP and DP methods. TFC in elephant dung coffee in both green and roasted condition was improved in contrast to the beans processed using dry and wet methods. The elephant dung coffee had an increased TTC in comparison to the DP and WP coffee (green beans). About 37 volatile compounds of acids, alcohols, aldehydes, amide, esters, ethers, furans, furanones, ketones, phenols, pyrazines, pyridines, Heterocyclic N, and pyrroles functional classes have been found. Some of the most abundant volatile compounds detected in all treatments of coffee were 2-furanmethanol, acetic acid, 2-methylpyrazine, 2,6-dimethylpyrazine, pyridine, and 5-methylfurfural. Few volatile compounds have been detected only in elephant dung coffee. The principal component analysis (PCAs) was performed using the percentage of relative peak areas of the volatile compound classes and individual volatile compounds. This study will provide a better understanding of the impacts of processing methods on the antioxidants and volatile compounds of coffee.

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Comparison of Extraction Methods for Caffeine, Chlorogenic Acids and Trigonelline in Green and Roasted Coffee Beans

10.13031/2013.7478 ◽

2001 ◽

Author(s):

Adriana S. Franca ◽

Leandro S. Oliveira ◽

Maria Lúcia A. Borges ◽

Vany P. Ferraz

Keyword(s):

Extraction Methods ◽

Chlorogenic Acids ◽

Roasted Coffee ◽

Coffee Beans ◽

Roasted Coffee Beans

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Temperature coverage simulation of horizontal cylinder type coffee roasting machine

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/922/1/012031 ◽

2021 ◽

Vol 922 (1) ◽

pp. 012031

Author(s):

F Fachruddin ◽

S Syafriandi ◽

R Fadhil

Keyword(s):

Bulk Density ◽

Horizontal Cylinder ◽

Roasted Coffee ◽

Actual Temperature ◽

Coffee Beans ◽

Roasting Process ◽

Study Results ◽

Roasting Temperature ◽

Roasted Coffee Beans ◽

Coffee Roasting

Abstract This study aims to simulate the temperature distribution of coffee roasting machines and study the profile of coffee beans roasted using a horizontal cylinder-type roaster. The coffee used in this study is arabica. The simulation method for the temperature estimation in the coffee roasting process uses the Solidworks Flow Simulation 2016 software, while the actual temperature measurement using a thermocouple is simulated with the Surfer software version 16. Furthermore, each stage of the coffee roasting process has been carried out, including the weight of the material, the roasting temperature, and the bulk density. The final step is to observe the profile of the roasted coffee beans at every minute of treatment. The study results indicate a difference between the approximate temperature simulation (top 176.85°C, bottom 191.97°C) and the actual temperature measured results (upper 214°C, bottom 220°C). The weight of the material (coffee green bean), the roasting temperature, and the bulk density during the test experienced regular movements from the beginning to the end of the treatment. The profile of roasted coffee beans shows a darker color movement along with the longer roasting time used. The profile of the roasted coffee beans will be beneficial in determining at which level of roasting you want (light, medium, medium-dark, dark).

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Analysis of Volatile Compounds Released during the Grinding of Roasted Coffee Beans Using Solid-Phase Microextraction

Journal of Agricultural and Food Chemistry ◽

10.1021/jf020724p ◽

2003 ◽

Vol 51 (7) ◽

pp. 1961-1969 ◽

Cited By ~ 65

Author(s):

Masayuki Akiyama ◽

Kazuya Murakami ◽

Noboru Ohtani ◽

Keiji Iwatsuki ◽

Kazuyoshi Sotoyama ◽

...

Keyword(s):

Volatile Compounds ◽

Solid Phase Microextraction ◽

Solid Phase ◽

Roasted Coffee ◽

Coffee Beans ◽

Roasted Coffee Beans

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Evaluation of DNA extraction methods from green and roasted coffee beans

Food Control ◽

10.1016/j.foodcont.2007.04.002 ◽

2008 ◽

Vol 19 (3) ◽

pp. 257-262 ◽

Cited By ~ 12

Author(s):

Stelios Spaniolas ◽

Maroussa Tsachaki ◽

Malcolm J. Bennett ◽

Gregory A. Tucker

Keyword(s):

Dna Extraction ◽

Extraction Methods ◽

Roasted Coffee ◽

Coffee Beans ◽

Dna Extraction Methods ◽

Roasted Coffee Beans

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Effect of Roasting Conditions on Concentration in Elements of Vietnam Robusta Coffee

Acta Universitatis Cibiniensis Series E Food Technology ◽

10.2478/aucft-2014-0011 ◽

2014 ◽

Vol 18 (2) ◽

pp. 19-34 ◽

Cited By ~ 1

Author(s):

Tran Van Cuong ◽

Liu Hong Ling ◽

Guo Kang Quan ◽

Shang Jin ◽

Song Shu Jie ◽

...

Keyword(s):

Absorption Method ◽

Roasted Coffee ◽

Robusta Coffee ◽

Flame Atomic Absorption ◽

Zn Concentration ◽

Coffee Beans ◽

Roasting Process ◽

Roasting Temperature ◽

Roasted Coffee Beans ◽

Pb Concentration

Abstract Vietnam Robusta Coffee was roasted at different roasting degree and roasting temperature and 9 element concentrations (K, Mg, Ca, Na, Fe, Cu, Mn, Zn and Pb) of roasted coffee were analyzed by Flame atomic absorption method (FAAS) in this study. The results showed that the concentrations were ranged in 1447.97 ~ 1342.10 (mg/100g), 768.22 ~ 1259.44 (μg/g),10.35 ~ 13.15 (μg/g), and 17.38 ~ 20.97 (μg/g) for element of K, Ca, Cu and Mn in green and roasted coffee beans, respectively. All determined elements were the smallest value in green coffee, then increased with increasing roasting level and reached the highest value in Spain roast (roasting temperature of 250°C). Mg concentration ranged in 682.70 ~ 3647.73 (μg/g); Fe concentration ranged in 37.20 ~ 53.44 (μg/g); Zn concentration ranged in 5.97 ~ 6.89 (μg/g) and Pb concentration ranged in 2.18 ~ 15.04 (μg/100g). Concentrations of all determined elements didn’t change with the increased roasting process.

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