Headspace Analysis of Philippine Civet Coffee Beans Using Gas Chromatography-Mass Spectrometry and Electronic Nose
ABSTRACT Civet coffee, the most expensive and best coffee in the world, is an economically important export product of the Philippines. With a growing threat of food adulteration and counterfeiting, a need for quality authentication is essential to protect the integrity and strong market value of Philippine civet coffee. At present, there is no internationally accepted method of verifying whether a bean is an authentic civet coffee. This study presented a practical and promising approach to identify and establish the headspace qualitative profile of Philippine civet coffee using electronic nose (E-nose) and gas chromatography-mass spectrometry (GC-MS). E-nose analysis revealed that aroma characteristic is one of the most important quality indicators of civet coffee. The findings were supported by GC-MS analysis. Principal component analysis (PCA) exhibited a clearly separated civet coffees from their control beans. The chromatographic fingerprints indicated that civet coffees differed with their control beans in terms of composition and concentration of individual volatile constituents.
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ABSTRACT: This research paper reports on the findings of the first scientific investigation into the various physicochemical properties of the palm civet (Kopi Luwak coffee bean) from Indonesia and their comparison to the first African civet coffee beans collected in Ethiopia in eastern Africa. Examination of the palm civet (Kopi Luwak) and African civet coffee beans indicate that major physical differences exist between them especially with regards to their overall color. All civet coffee beans appear to possess a higher level of red color hue and being overall darker in color than their control counterparts. Scanning electron microscopy revealed that all civet coffee beans possessed surface micro-pitting (as viewed at 10,000× magnification) caused by the action of gastric juices and digestive enzymes during digestion. Large deformation mechanical rheology testing revealed that civet coffee beans were in fact harder and more brittle in nature than their control counterparts indicating that gestive juices were entering into the beans and modifying the micro-structural properties of these beans. SDS–PAGE also supported this observation by revealing that proteolytic enzymes were penetrating into all the civet beans and causing substantial breakdown of storage proteins. Differences were noted in the types of subunits which were most susceptible to proteolysis between civet types and therefore lead to differences in maillard browning products and therefore flavor and aroma profiles. This was confirmed by electronic nose analysis which revealed differences between the palm civet coffee (Kopi Luwak) and African civet coffee aroma profiles. Analytical techniques for the authentification of palm civet (Kopi Luwak) and African civet coffee are also explored. It would appear that SDS–PAGE may serve as the most reasonable and reliable test to help confirm the authenticity of civet coffee. Electronic nose data was able to distinguish both civet coffees from their control counterparts and further indicated that processing through the civets gastro-intestinal track substantially modified these coffees.Food Research International - FOOD RES INT. 01/2004; 37(9):901-912.
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ABSTRACT: This study is the second of two publications that investigate the interactions between volatile and nonvolatile components in coffee brew. The purpose here was to shed some light into the chemical mechanisms responsible for the decrease of volatile thiols when in contact with coffee nonvolatiles. A mixture of volatile thiols covering a large range of physicochemical properties was monitored over time in the presence of a coffee brew model. The binding potential was estimated by SPME-GC-MS. Additives inhibiting specific reaction pathways were preincubated with the coffee brew 1 h prior to addition of the volatile compounds. Degradation kinetics of the volatile thiols were characterized by their rate constants k(obs). The effect of individual additives was shown by calculating k(rel), the relative rate constant as compared to the reference without additive. The conclusion was that thiols, mainly responsible for the "roasty" and "burnt" notes, disappear via two main chemical mechanisms. The results suggest that nucleophilic addition is the major pathway for thiol degradation. Addition occurs on oxidized species generated in the matrix in the presence of air. This mechanism prevails for aliphatic thiols (e.g., ethanethiol, methanethiol). Benzylic thiols (such as 2-furfurylthiol) can react in parallel via another pathway that is slowed in the absence of oxygen and in the presence of a radical scavenger. This points to a radical mechanism, but further work is needed to support this hypothesis. A direct correlation between thiol hydrophobicity and the magnitude of the interactions was shown as well. Therefore, weak physical interactions or hydrophobic assistance accelerating chemical reactions cannot be excluded at this point of the study.Journal of Agricultural and Food Chemistry 07/2005; 53(11):4426-33. · 3.11 Impact Factor
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ABSTRACT: An electronic nose system for quality control of coffee is designed and tested. The system uses the Figaro TGS800 series sensors with an integrated heating element. The testing of the system is carried out using different types of coffee where it is proved successful in classifying the tested coffees and actual discrimination of ingredients into different classes . Database based software is designed to interface the built hardware and to process the electronic nose signals before being classified.American Journal of Applied Sciences. 01/2004;
Procedia Engineering 47 ( 2012 ) 977 – 980
1877-7058 © 2012 Elsevier Ltd....Selection and/or peer-review under responsibility of the Symposium Cracoviense Sp. z.o.o.
Proc. Eurosensors XXVI, September 9-12, 2012, Kraków, Poland
Chemometric Discrimination of Philippine Civet Coffee
Using Electronic Nose and Gas Chromatography Mass
E. Ongoa,b, M. Falasconic, G. Sberveglieric, A. Antonellid, G. Montevecchid,
V. Sberveglierid, I. Concinac, F. Sevilla IIIb*
Industrial Technology Development Institute, DOST, Gen. Santos Ave., Bicutan, Taguig City, 1631 Philippines
University of Santo Tomas, Graduate School , Espana Blvd Blvd., Sampaloc, Manila, 1008 Philippines
CNR-IDASC SENSOR & Brescia University, Via Valotti 9, 25133 Brescia, Italy
Dipartimento di Scienze-Agrarie e degli Alimenti, Universita di Modena e Reggio Emilia, Via, G. Amendola 2, 42122 Reggio
This study presents a practical and promising approach to profile the headspace aroma attributes of Philippine
civet coffee using electronic nose (E-nose) and gas chromatography mass spectrometry (GCMS). Chemometric
pattern method was applied to enhance the discrimination of civet coffee against its control coffee beans (not eaten by
civet animal). E-nose analysis revealed that aroma characteristic is one of the most important quality indicators of
civet coffee. The result was supported by GCMS analysis. The chromatographic fingerprints indicated that civet
coffee differed with their control beans in terms of composition and concentration of individual volatile constituents.
Chemometric discrimination of E-nose and GCMS data demonstrated a clearly separated civet from their control
coffees indicating that cultivar and geographic origins dictate the aroma and volatiles variations in coffee.
© 2012 Published by Elsevier Ltd.
© 2012 Elsevier Ltd....Selection and/or peer-review under responsibility of the Symposium Cracoviense Sp. z.o.o.
Keywords: civet coffee: electronic nose; gas chromatography mass spectrometry; chemometric discrimination
Civet coffee is the top most expensive coffee in the world . It is made from coffee cherries, which
have been eaten and passed through the digestive tract of Asian palm civet (Paradoxurus
* Corresponding author. Telefax.: +632-7314031
E-mail address: firstname.lastname@example.org
Available online at www.sciencedirect.com
978 E. Ongo et al. / Procedia Engineering 47 ( 2012 ) 977 – 980
hermaphroditus). Civets naturally select and consume the ripest and sweetest coffee cherries whereby the
undigested inner beans are excreted.The unique aroma and flavor quality of civet coffee has been
associated to the breaking down of proteins during civet digestion . The increasing popularity and
appreciation of civet coffee and its limited annual supply could possibly lead to the occurrence of
adulterated and fraudulent civet coffee beans in the market. It is therefore important to discriminate civet
coffee from non-civet coffee. At present, there is no internationally accepted method of verifying whether
a bean is civet coffee. Traditionally, coffee aroma has been used to characterize coffee quality. The
volatile compounds in coffee contribute greatly to its overall aroma quality .
Sensory panel evaluation is commonly used to assess the aroma profile of coffee. However, this
technique has some drawbacks such as the difficulty to train the panel effectively in order to limit
subjectivity of human response to odors and the variability between individuals . The emergence of an
electronic nose (E-nose) for the discrimination of odors has become attractive and useful to the food
industry because of its ease of use, versatility, and broad range of applications . Similarly, the
application of GCMS in coffee analysis has proven to be a valuable technique to characterize the volatile
compounds responsible for the aroma quality of coffee . In this work, E-nose and GCMS analysis of
Philippine civet coffee were carried out for the first time to determine the potential of the instruments to
discriminate civet coffees with their control coffee beans (not eaten by civet). Chemometric analysis was
applied to visually display the similarities and distinction between civet and control coffee beans.
2.1 Coffee Samples and Instruments
Four different commercial brands of Philippine coffees were analyzed. Three coffees (civet and
control) were taken from Northern part of Luzon (Kalinga, Asipulo, and Cordillera) and one from
southern part of the Philippines (Matutum, South Cotabato). The coffee samples were Arabica (Cordillera
and Matutum) and Robusta (Asipulo and Kalinga) varieties.
The Electronic Olfactory System, EOS835 was manufactured by Sacmi Imola scarl, Italy . E-nose
analysis was carried out using six metal oxide (MOX) sensors whose characteristics and fabrication
parameters are shown in Table 1. Headspace generation was held at 40 °C for 10 min with 1 min shaking.
Then, 2 ml volume was extracted and injected into carrier line at 50 °C with injection speed of 4 ml/min.
Table 1. Metal oxide (MOX) sensors characteristics.
No. Sensing layer
Catalyst Operating T
a Tin Oxide-Rheotaxial Growth and Thermal Oxidation technique
b Tungsten Oxide
c Tin-Indium Oxide
CA, USA equipped with crossbond carbowax capillary column (Restek 11023). Headspace was generated
at 70 °C for 10 min and volatiles extraction at 70 °C for 20 min.
GCMS analysis was performed using Hewlet Packard GCMS model HP6890/5973 (Hewlett Packard,
E. Ongo et al. / Procedia Engineering 47 ( 2012 ) 977 – 980
3. Results and Discussion
The responses of the MOX sensors to the coffee samples varied greatly. A comprehensive view of the
PCA score plot of the E-nose data is illustrated in Figure 1 and the dendrogram graph is shown in Figure
2. Chemometric analysis through principal component analysis (PCA) and cluster analysis reveals
groupings that differentiate civet and non-civet (control) coffee. The discrimination indicates that the
headspace vapor, and therefore the aroma of each civet coffee is different from their corresponding
control coffee beans. The distinct data structure of the individual civet coffee shows that the passage of
the beans through the digestive tract of civet affects the aroma attributes of coffee .
Fig. 1. E-nose PCA plot of civet and control coffee beans. Fig. 2. Dendrogram of civet and control coffee beans.
Data obtained from gas chromatography-mass spectroscopy (GCMS) indicates the presence of at least
47 major components (Figure 3) in the headspace of civet and non-civet (control) coffees. It was observed
that the composition of volatile compounds in civet coffee is almost similar to their controls but of
different concentrations. PCA plot (Figure 4) of prominent coffee volatiles exhibits a good classification
between civet and control coffee beans. The separation in the GCMS-PCA plot between civet and control
coffees is complementary with the E-nose results. Chemometric discrimination of civet from non-civet
coffee reveals that the aroma characteristic is one of the most important quality indicators of civet coffee.
Fig. 3. GCMS chromatographic profile of civet and
control coffee beans
Fig. 4. GCMS PCA plot for civet and control coffee beans.
The integration of E-nose and GCMS data of the PCA plot shown in Figure 5 reveals a good
correlation between aroma quality and coffee volatiles of civet coffee considering that individual civet
980 E. Ongo et al. / Procedia Engineering 47 ( 2012 ) 977 – 980
coffee was successfully discriminated with its control beans. Cluster separation among civet coffees
suggested that the aroma quality of civet coffee is region-specific. Results provide proof that E-nose is a
promising and practical tool in evaluating the authenticity of civet coffee.
Fig. 5. PCA plot of E-nose and GCMS data for civet and control coffee beans.
E-nose (EOS835) has proven to be useful in discriminating the aroma quality of Philippine civet
coffee. The finding was supported by the differences between the relative GCMS traces of the different
coffees. Chemometric analysis through PCA and cluster analysis demonstrated groupings that
differentiate civet and non-civet coffee. Results revealed that aroma characteristic is one of the most
important quality indicators of civet coffee. The unique aroma quality of civet coffee can be attributed to
the intestinal digestive process of civet. The cluster separation among civet coffee samples indicated that
varietal and geographical origins dictate the aroma variations in coffee. Thus, it can be concluded that the
aroma characteristics of civet coffee is varietal and region-specific. This remarkable performance
provides proof that E-nose can be used in discriminating the authentic aroma quality of civet coffee.
This research work was funded by the Philippine Council for Industry, Energy and Emerging
Technology Research and Development?(PCIEERD), Department of Science and Technology (DOST),
Philippines, the University of Modena and Reggio Emilia and the University of Brescia, Italy. One of the
authors (E.O) gratefully acknowledges the sandwich thesis grant provided to her by DOST-PCIEERD.
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