Effects of Coffee Processing Technologies on Aroma Profiles and Sensory Quality of Ruiru 11 and SL 28 Kenyan Coffee Varieties.


  • R. Kipkorir Dedan Kimathi University of Technology
  • S. Muhoho Jomo Kenyatta University of Agriculture and Technology
  • P. Muliro Egerton University,
  • B. Mugendi Dedan Kimathi University of Technology
  • M. Frohme Technical University of Applied Sciences, Wildau
  • O. Broedel Technical University of Applied Sciences, Wildau


Coffee, processing, aroma, sensory quality.


The study aimed at comparing the effects of three coffee processing methods on aroma profiles and sensory quality of Ruiru 11 and SL 28 coffee varieties. The processing methods varied on stages of processing and method of mucilage removal. The green coffee beans obtained from the three processing methods were graded and roasted, ground and analyzed for the aroma profiles and sensory quality. Headspace Solid phase Microextraction fibre (SPME) technique were used for the extraction of aroma compounds from coffee samples and characterization of the compounds with use of gas chromatography mass spectrometry (GC-MS). Sensory quality were analyzed by an expert panelist. Various volatile aroma compounds were identified in roasted coffee and classified into their chemical classes involving furans, ketones, pyrazines ketones pyridines, pyrroles and acids. The intensity of aroma compounds were compared in terms of their peak areas and variations were noted between the processing methods with the ecopulper showing higher levels of pyrazines such as 2-methylpyrazine, 2-ethyl-6-methylpyrazine, and wet pulper showing higher levels of furans such as furfuryl formate and furfuryl alcohol, acetate. The hand pulper was high in the level of acids and esters such as acetic acid and propanoic acid, ethyl ester. Similar aroma compounds were identified in headspace of Ruiru 11 and SL 28 and there were variations in the intensities of aroma groups such as pyrroles and pyridines. It was concluded that the eco-pulper and hand pulper methods gives better aroma quality than the wet pulper while SL 28 variety gives higher sensory quality than Ruiru 11.

Author Biographies

R. Kipkorir, Dedan Kimathi University of Technology

Assistant Lecturer, Institute of Food Bioresorces Technology

S. Muhoho, Jomo Kenyatta University of Agriculture and Technology

Department of Food Science and Technology

P. Muliro, Egerton University,

Department of Dairy and Food Science and Technology

B. Mugendi, Dedan Kimathi University of Technology

Institute Food Bioresources Technology

M. Frohme, Technical University of Applied Sciences, Wildau

Department of Molecular Biotechnology and Functional Genomics

O. Broedel, Technical University of Applied Sciences, Wildau

Department of Molecular Biotechnology and Functional Genomics


Baltes, W., Bochmann, G. Model reactions on roast aroma formation, Mass-spectrometric identification of furans and furanones from the reaction of serine and threonine with sucrose under the conditions of coffee roasting. Journal of Agriculture and food chemistry 184: 179-186, 1987.

Bhumiratana, N., Adhikari, K. and Chambers, IV, E.. Evolution of sensory aroma attributes from coffee beans to brewed coffee. Food Science and Technology 44: 2185-2192, 2011

Brohan, M., Huybrighs, T., Wouters, C. and Bruggen, B. V. Influence of storage conditions on aroma compounds in coffee pads using static headspace GC-MS. Food Chemistry 116: 480-483, 2009

Budryn, G., Nebesn y E, Kula J., Majda T.and Krysiak W. HS-SPME/GC/MS Profiles of Convectively and Microwave Roasted Ivory Coast Robusta Coffee Brews, Czech J. Food Sci. 29: 151–160, 2011

Clarke R.J. The volatile compounds of roasted coffee. Italian Journal of Food Science, 2: 79–88, 1990.

Fisk I. D., Kettle A., Hofmeister S., Virdie A. and Kenny J. S. Discrimination of roast and ground coffee aroma. Flavour. 1:14, 4-8, 2012.

Gonzalez-Rios O, Suarez-Quiroz ML, Boulanger R, Barel M, Guyot B, Guiraud J-P, Schorr-Galindo S. Impact of “ecological†post-harvest processing on coffee aroma: II. Roasted coffee. J Food Compos Anal, 20:297–307, 2007

Kathurima C, Kenji G, Muhoho S, Boulanger R, Ng’ang’a F.Volatile organic compounds in brewed Kenyan Arabica coffee genotypes by solid phase extraction gas chromatography mass spectrometry. Food Sci. Qual. Manage, 8: 18-26, 2012

Kathurima, C.W, Gichimu, B.M., Kenji, G.M., Muhoho, S.M and Boulanger, R. Evaluation of beverage quality and green bean physical characteristics of selected Arabica coffee genotypes in Kenya. African Journal of Food Science 3 (11): 365-371, 2009

Madihah, K. K.Y., Zaibunnisa, A.H., Norashikin, S., Rozita, O. and Misnawi, J. Optimization of roasting conditions for high-quality Arabica coffee, International Food Research Journal 20(4): 1623-1627, 2013.

Mondello, L., Costa, R., Tranchida, P.Q., Dugo, P., Presti, M.L., Festa, S., Fazio, A. and Dugo, G. Reliable characterization of coffee bean aroma profiles by automated headspace solid phase micro-extraction-gas chromatography-mass spectrometry with the support of a dual-filter mass spectra library. Journal of Separation Science. 28:1101–1109, 2005

Murthy P. S. and Naidu M. M. Improvement of Robusta Coffee Fermentation with Microbial Enzymes, 3 (4): 130-139, 2011.

Nebesny E. Budryn G. Kula J. and Majda T. The effect of roasting method on headspace composition of robusta coffee bean aroma, Eur Food Res Technol , 225:9–19, 2007

Nebesny E, Budryn G. Evaluation of sensory attributes of coffee brews from Robusta coffee roasted under different conditions. Eur. Food Res. Technol. 224:159 -165, 2006

Nigam P.S., Singh A. Cocoa and Coffee Fermentations. Encyclopedia of Food Microbiology (Second Edition), Pages 485-492, 2014

Petisca C., Pérez-PalaciosT., Farah A. and Pinho O, Isabel M.P.L.V.O. F. Furans and other volatile compounds in ground roasted and espresso coffee using headspace solid-phase microextraction: Effect of roasting speed, Food and bioprod. Process. 9 1 : 233–241, 2013.

Ribeiro J.S., Augusto F., Salva T.J.G. Thomaziello R.A., FerreiraM.M.C. Prediction of sensory properties of Brazilian Arabica roasted coffees by headspace solid phase microextraction-gas chromatography and partial least squares, Analytica Chimica Acta 634 :172–179, 2009

Roa G., Oliveros C. E., Alvarez J., Sanz J. R., Ramirez C A., Dávila M. T., Alvarez J. R., Zambrano D. A., Puerta G. I., Rodriguez N. Ecological Processing of Coffee at The Farm Level. Cenicafe. http://www.ctahr.hawaii.edu/hawaii/downloads/Low_Water_use_processing.pdf Web Visited on January 2012.

Semmelroch P, Grosch W: Analysis of roasted coffee powders and brews by gas chromatography-olfactometry of headspace samples. LWT Food Sci Technol, 28:310–313, 1995

Yener S., Romano A., Cappellin L., Märk, D.T., Sánchez del Pulgar J. Gasperi, F., Navarini L. and Biasioli F. PTR-ToF-MS characterisation of roasted coffees (C. arabica) from different geographic origins. J. Mass Spectrom. 49: 929–935, 2014.




How to Cite

Kipkorir, R., Muhoho, S., Muliro, P., Mugendi, B., Frohme, M., & Broedel, O. (2015). Effects of Coffee Processing Technologies on Aroma Profiles and Sensory Quality of Ruiru 11 and SL 28 Kenyan Coffee Varieties. Asian Journal of Agriculture and Food Sciences, 3(2). Retrieved from https://ajouronline.com/index.php/AJAFS/article/view/2551