Arabica Samples Research Articles

Chemical composition and sensory profiling of coffees treated with asparaginase to decrease acrylamide formation during roasting

Acrylamide is an amide formed in the Maillard reaction, with asparagine as the primary amino acid precursor. The intake of large amounts of acrylamide has induced genotoxic and carcinogenic effects in hormone-sensitive tissues of animals. The enzime asparaginase is one of the most effective methods for lowering the formation of acrylamide in foods such as potatoes. However, the reported sensory outcomes for coffee have been unsatisfactory so far. This study aimed to produce coffees with reduced levels of acrylamide by treating them with asparaginase while retaining their original sensory and bioactive profiles. Three raw samples of Coffea arabica, including two specialty coffees, and one of Coffea canephora were treated with 1000, 2000, and 3000 ASNU of the enzyme. Asparagine and bioactive compounds (chlorogenic acids-CGA, caffeine, and trigonelline) were quantified in raw and roasted beans by HPLC and LC-MS, while the determination of acrylamide and volatile organic compounds was performed in roasted beans by CG-MS. Soluble solids, titratable acidity, and pH were also determined. Professional cupping by Q-graders and consumer sensory tests were also conducted. Results were analyzed by ANOVA-Fisher, MFA, PCA and Cluster analyses, with significance levels set at p ≤ 0.05. Steam treatment alone decreased acrylamide content by 18.4%, on average, and 6.1% in medium roasted arabica and canefora coffees. Average reductions of 32.5–56.0% in acrylamide formation were observed in medium roasted arabica beans when 1000–3000 ASNU were applied. In the canefora sample, 59.4–60.7% reductions were observed. However, steam treatment primarily caused 17.1–26.7% reduction of total CGA and lactones in medium roasted arabica samples and 13.9–22.0% in canefora sample, while changes in trigonelline, caffeine, and other evaluated chemical parameters, including the volatile profiles were minimal. Increasing enzyme loads slightly elevated acidity. The only sensory changes observed by Q-graders and or consumers in treated samples were a modest increase in acidity when 3000 ASNU was used in the sample with lower acidity, loss of mild off-notes in control samples, and increased perception of sensory descriptors. The former was selected given the similarity in chemical outcomes among beans treated with 2000 and 3000 ASNU loads.

LC-MS methods combination for identification and quantification of trans-sinapoylquinic acid regioisomers in green coffee.

The present study aims to both identify and quantify trans-sinapoylquinic acid (SiQA) regioisomers in green coffee by combined UHPLC-ESI-QqTOF-MS/MS and UHPLC-ESI-QqQ-MS/MS methods. Among the various mono-acyl chlorogenic acids found in green coffee, SiQA regioisomers are the least studied despite having been indicated as unique phytochemical markers of Coffea canephora (known as Robusta). The lack of commercially available authentic standards has been bypassed by resorting to the advantages offered by high-resolution LC-MS as far as the identification is concerned. SiQA regioisomers have been identified in several samples of Robusta and Coffea arabica (known as Arabica) commercial lots from different geographical origin and, for the first time, in different samples of coffee wild species (Coffea liberica and Coffea pseudozanguebariae). Quantification (total SiQA ranging from 3 to 5mg/100 g) let to reconsider these chlorogenic acids as unique phytochemical markers of Robusta being present in the same quantity and distribution in C.liberica as well. Gardeniae Fructus samples (fruits of Gardenia jasminoides) have additionally been characterized as this matrix is recognized as one of the few naturally occurring SiQA sources. The SiQA regioisomer content (total SiQA about 80 mg/100 mg) fully supports the proposal to use this matrix as a surrogate standard for further studies.

Genetic profiling of locally registered Philippine coffee using molecular markers linked to resistance against diseases and pests

Abstract. Santos NRS, Magat MB, Mondragon MV, Cao EP, Santos DMC. 2023. Genetic profiling of locally registered Philippine coffee using molecular markers linked to resistance against diseases and pests. Biodiversitas 24: 4136-4144. Coffee is a major commodity in the Philippines, but diseases and pests have hampered local production. Natural resistance could help increase production by eradicating infestation or lessening the symptoms of infection and minimizing the need for chemical control. Hence, this study aims to screen local Coffea arabica varieties, whose beans are prized for their superior taste and aroma, using genetic markers. These markers are linked to resistance against Coffee Leaf Rust (CLR, caused by Hemileia vastatrix), Coffee Berry Disease (CBD, caused by Colletotrichum kahawae), and Root Knot Nematode (RKN, Meloidogynespp.). The Arabica samples were obtained from the Bureau of Plant Industry in Baguio City, Benguet, a main distributor of coffee seedlings to farmers. C. canephora and C. liberica trees from Cavite State University, Indang, Cavite, were used as control samples. Results reveal that the registered NSIC-2008-Cf-A-05 (Red Bourbon) Arabica tree contains a unique haplotype in a region of chromosome 3. This region has been linked to the SH3 gene, which confers resistance against CLR, a promising result for infested areas. However, all Arabica samples are inferred to be susceptible to CBD and RKN. Hence, NSIC-2008-Cf-A-05 is a potential source for resistance genes specifically against CLR in future breeding programs.

Screening of yield and growth-related SSR markers in Philippine coffee

Yield is a complex trait affected by numerous factors, such as disease resistance, bean size and shape. Molecular markers such as simple sequence repeats (SSRs) can identify quantitative trait loci (QTL) associated with yield. For this study, SSR markers related to yield and growth, such as genes coding for certain protein kinases and ligases, were mined from the available Coffea canephora reference genome. A total of 100 SSR markers were screened using C. arabica (commonly known as Arabica coffee), C. canephora (commonly called as Robusta coffee), C. liberica var. liberica (locally known as Liberica coffee or Kapeng Barako) and C. liberica var. dewevrei (locally called as Kapeng Excelsa) as samples. These types have their own unique growth and yield characteristics making them suitable for comparison. Of the 82 loci successfully amplified, 46 loci were polymorphic. A total of 66 bands from 37 loci were specific to certain types. Nineteen (19) bands were specific to Arabica samples, five for Robusta, three for Liberica, and another three for Excelsa. The other remaining bands were shared by a combination of two or three types. Forty-six bands were found near genes annotated as enzymes that promote plant growth and the ability to respond and adapt to environmental signals like light, hormones and stress factors. The bands specific to Robusta might explain its moderate resiliency to abiotic stress conditions and better yield compared to the other species. These bands are indicative of genetic differences in the yield-related target loci. As such, these markers have great potential in marker-assisted selection for yield and growth improvement of Philippine coffee. This study is the first to identify potential yield and growth-related SSR markers in Philippine coffee types.

Volatile Compound Analysis to Authenticate the Geographical Origin of Arabica and Robusta Espresso Coffee

The traceability of the geographical origin of coffee is a challenging issue to protect producers and consumers from the risk of fraud. A total of 162 Arabica from Peru, Colombia and Brazil, and Robusta from India, Vietnam and Uganda, espresso coffee (EC) samples of different degrees of roasting (light, medium and dark) were characterized for physico-chemical features (lipids, solids, and chlorogenic acids) and analyzed via SHS-GC/MS analysis, with the aim of discriminating the samples according to their geographical origin. Linear discriminant analysis (LDA), performed on the data of the chemical classes of the volatile organic compounds (VOCs), was able to correctly identify 97.53% of the tested samples through cross-validation. The dark roasting of the coffee beans implied a higher quantity of volatile compounds in the headspace of the EC, belonging to chemical classes of furans, esters, N-heterocyclic and sulfur compounds, reducing the differences by geographical origin. Light- and medium-roasted Robusta EC showed a major contribution of pyrazines and pyrimidines, while aldehydes, alcohols and ketones were generally more representative in Arabica samples. The quantitative distribution of volatile compounds proved to be a useful tool to discriminate samples by geographical origin.

Food borne toxicants in coffee: Acrylamide and furan derivative content in Arabica and Robusta coffees with different roasting profiles and varying degrees of roast

<sec><title/> To evaluate mitigation options for both acrylamide and furan and methylfurans a Vietnam Robusta grade 2 and a Brazil Arabica (unwashed) were roasted by tangential, drum and hot air roasting. Three different roasting profiles were followed and three samples (light, medium and dark roast) were obtained per profile. Decaffeinated and steam treated batches of the two coffees were roasted. Special roasts, such as double roast (on 2 days with cooling down in between) or roasting with a sudden temperature change were studied. The contaminants were analyzed by GC-MS – in case of the furans headspace GC-MS – using deuterated standards. </sec><sec><title/> The acrylamide contents were highest in light roasts, and decreased after that with longer roasting time. This was true for both the Robusta and Arabica samples. The content of furan and 2-, 3- and 2-5-methylfurans were low in light roasts and had a maximum in dark roasts. It is possible to minimize the content of either acrylamide and furans, however, a mitigation of both could not be established by changing the roasting parameters or using pretreatments. Among the furans determined 2-methylfuran was most abundant (average around 70%), followed by furan (average around 20%). The special roasts showed no options to minimize both contaminants as did the pretreatments. In the Vietnam Robusta furan related compounds were measured. 5-hydroxymethylfurfural and 5-hydroxymethylfurfuryl-2-carboxylic acid decreased with the degree of roast and time, while furfuryl alcohol and 2-furoic acid contents increased. </sec>

Comprehensive Analysis of Metabolites in Brews Prepared from Naturally and Technologically Treated Coffee Beans.

Coffee is one of the most popular beverages in the world. Therefore, this study analyzed 49 coffee samples of Arabica and Robusta species of different geographical origins and the treatment of beans including three degrees of roasting with the use of LC-MS/MS. This is the first study to present a comprehensive analysis of Kopi Luwak coffee brew metabolites in comparison to fully washed coffees and the drying post-harvest treatment of Arabica or Robusta coffee brews. Kopi Luwak showed higher levels of caffeine and theophylline in comparison to the analyzed washed and unwashed Arabica coffees, as well as a different proportion of caffeoylquinic isomers. There was no difference between Kopi Luwak and other Arabica coffees in terms of the concentration of vitamin B3, amines, and phenolic acids. This was confirmed in PCA. The steaming and roasting of beans as well as the addition of black beans influence the concentration of 4-CQA and the nicotinic, ferulic, and quinic acids content.

CHANGES IN TEXTURAL PROPERTIES AND COLOR DUE TO THE PROCESSING METHOD OF GREEN COFFEA ARABICA

Choosing a suitable method of green coffee beans processing is one of the first steps that can significantly affect the final product. Thus, the objective of this study was to evaluate how the processing method affects the selected observed parameters (dry matter, water activity, pH, hardness, color). The postharvest processing of coffee cherries involves natural dry, semi-washed, or wet processing. On-farm postharvest coffee processing is essential for ensuring high quality of coffee cup and constitutes a chain of interlinked phases mainly aimed at removing the cherries' mucilage and drying the beans to a low moisture content of 10 to 12% (mass/mass). The coffee samples were of American origin Coffea arabica. A total of 12 samples from multiple regions were used. Samples of Coffea arabica were collected into three groups natural (dry), pulped natural (semi-washed), and wet processing (fully washed). The processing results, to some extent, influence the values ​​​​of the monitored parameters. The highest dry matter value was indicated in dry processing, and the highest value of water activity was in wet processing. The average value of pH was 5.74. Natural processing showed the most significant differences between individual groups concerning color processing. On the other hand, wet and dry processing showed very similar colors. Values of hardness were in range 86549.05 - 100674.90 g. The final quality of the green coffee beans is thus dependent on the different agricultural, and farm practices applied, which depend on the coffee plant cultivar, geography, weather conditions, and available infrastructure.

Assessing the Levels of Robusta and Arabica in Roasted Ground Coffee Using NIR Hyperspectral Imaging and FTIR Spectroscopy.

It has been reported that some brands of roasted ground coffee, whose ingredients are labeled as 100% Arabica coffee, may also contain the cheaper Robusta coffee. Thus, the objective of this research was to test whether near-infrared spectroscopy hyperspectral imaging (NIR-HSI) or Fourier transform infrared spectroscopy (FTIRs) could be used to test whether samples of coffee were pure Arabica or whether they contained Robusta, and if so, what were the levels of Robusta they contained. Qualitative models of both the NIR-HSI and FTIRs techniques were established with support vector machine classification (SVMC). Results showed that the highest levels of accuracy in the prediction set were 98.04 and 97.06%, respectively. Quantitative models of both techniques for predicting the concentration of Robusta in the samples of Arabica with Robusta were established using support vector machine regression (SVMR), which gave the highest levels of accuracy in the prediction set with a coefficient of determination for prediction (Rp2) of 0.964 and 0.956 and root mean square error of prediction (RMSEP) of 5.47 and 6.07%, respectively. It was therefore concluded that the results showed that both techniques (NIR-HSI and FTIRs) have the potential for use in the inspection of roasted ground coffee to classify and determine the respective levels of Arabica and Robusta within the mixture.

Comprehensive Composition of Flavor Precursors in Kopi Luwak and Jacu Exotic Green Bioprocessed Coffees

Exotic coffees may be defined as extravagant and unique coffees, primarily due to their production mode, including unusual bioprocessing or fermentation conditions associated with superior sensorial characteristics. The aim of the present study was to investigate the influence of bioprocessing and of growing conditions on flavor precursors of Jacu and Kopi Luwak exotic green coffees, respectively. Moreover, this is the first study to perform a detailed chemical analysis of these exotic coffees. Thirteen green Coffea arabica bean samples were obtained, five from Espírito Santo state, Brazil, and eight Kopi Luwak from different regions of Indonesia. Samples were analyzed regarding their proximate composition, chlorogenic acids (CGA), sucrose, alkaloids, triacylglycerols (TAG), diacylglycerols, free fatty acids, sterols, diterpenes and tocopherols. Scanning electron micrography confirmed bioprocessing of Jacu and Kopi Luwak coffee samples. Bioprocessing by the Jacu bird caused reductions of 69 and 28% in caffeine and CGA contents, respectively. The TAG profile of Jacu coffee was modified. TAG containing two saturated fatty acids were preferably hydrolyzed in detriment to those containing two unsaturated fatty acids. Other coffee components were not affected by the bird's digestion of the beans. Kopi Luwak coffee samples had a chemical composition in accordance with reported ranges for non-bioprocessed green C. arabica samples, except for caffeine (0.48 g/100 g) and CGA (5.09 g/100 g), which were found in low amounts. Crop year rather than location or post-harvest processing discriminated Kopi Luwak coffee samples, suggesting that weather conditions would be the most crucial aspect for their chemical composition, especially in terms of total lipids, ashes, total CGA, sucrose and proteins.

Acrylamide: impact of precursors concentration, origin, post‐harvesting process and roasting level in high‐quality arabica and Robusta coffee

SummaryOrigin of coffee, precursors concentration, post‐harvesting processes and commercial roasting degrees were evaluated for their impact on acrylamide content in roasted coffee. Forty Seven Specialty Arabica and 7 high‐quality Robusta green coffee samples were analysed to determine sugars, asparagine and Aw. Acrylamide was quantified on light, medium and dark roasted samples. In green coffee, glucose and fructose content resulted lower after wet and honey processes, no remarkable differences were found for sucrose and asparagine. In all samples, the content of asparagine was generally lower than what provided in previous works. Acrylamide concentration never exceeded the limit of 400 μg kg−1 in Arabica samples and it does once in Robusta, it peaked between light and medium roasting, and it was higher in Robusta. Moreover, it was lower in honey coffee than in others. Acrylamide correlated with asparagine in Robusta, while with monosaccharides and Aw in dry and honey Arabica. Coffee Origin impacted on precursors and acrylamide.

Multi-mycotoxin determination in coffee beans marketed in Tunisia and the associated dietary exposure assessment

Coffee is an agricultural product highly susceptible to mycotoxin contamination. The present study evaluates the natural presence of 17 mycotoxins in different types of coffee sampled in Tunisia (n = 100), by using liquid chromatography-tandem mass spectrometry methods (LC-MS/MS). The results showed that all the analyzed samples were contaminated by at least one mycotoxin. Tentoxin (TENT) was registered in 95 samples with maximum of 300 μg/kg while aflatoxin B1 (AFB1) and ochratoxin A (OTA) in 7 and 18 samples, respectively. Most of OTA positive samples exceeded the OTA maximum regulatory limit (MRL). The highest levels of OTA, aflatoxin G1 (AFG1), and alternariol monomethyl ether (AME) levels were detected in Arabica samples reaching up to 122.6; 186.9 and 388.6 μg/kg, respectively. 82 samples were contaminated by at least two mycotoxins and up to nine different mycotoxins co-occurred simultaneously in two samples. The dietary exposure of the Tunisian population was also assessed, and the probable daily intake (PDI) ranged between 0.27– 1.48 and 2.79–5.28 ng/kg bw/day for OTA and zearalenone (ZEN), respectively. It was also found that, at the worst scenario (Mp), consumers may be reaching up to 2.1% and 8.7% of the tolerable daily intakes (TDIs) of ZEN and OTA, respectively. However, no toxicological risk arises to most of the analyzed mycotoxins from the regular consumption of the evaluated coffee.

Effect of the Post-Harvest Processing on Protein Modification in Green Coffee Beans by Phenolic Compounds.

The protein fraction, important for coffee cup quality, is modified during post-harvest treatment prior to roasting. Proteins may interact with phenolic compounds, which constitute the major metabolites of coffee, where the processing affects these interactions. This allows the hypothesis that the proteins are denatured and modified via enzymatic and/or redox activation steps. The present study was initiated to encompass changes in the protein fraction. The investigations were limited to major storage protein of green coffee beans. Fourteen Coffea arabica samples from various processing methods and countries were used. Different extraction protocols were compared to maintain the status quo of the protein modification. The extracts contained about 4–8 µg of chlorogenic acid derivatives per mg of extracted protein. High-resolution chromatography with multiple reaction monitoring was used to detect lysine modifications in the coffee protein. Marker peptides were allocated for the storage protein of the coffee beans. Among these, the modified peptides K.FFLANGPQQGGK.E and R.LGGK.T of the α-chain and R.ITTVNSQK.I and K.VFDDEVK.Q of β-chain were detected. Results showed a significant increase (p < 0.05) of modified peptides from wet processed green beans as compared to the dry ones. The present study contributes to a better understanding of the influence of the different processing methods on protein quality and its role in the scope of coffee cup quality and aroma.

Authentication of Six Indonesian Ground Roasted Specialty Coffees According to Variety and Geographical Origin using NIR Spectroscopy with Integrating Sphere

Several factors such as type of bean (Arabica or Robusta), geographical origin (elevation, soil type, temperature, and solar radiation), and agronomic/postharvest practices (fertilization, bean processing, fermentation, and type of roasting) have a great influence on the quality of final taste of the coffee. In this research, an authentication of six Indonesian ground roasted specialty coffees according to different in variety and geographical origin using NIR spectroscopy with integrating sphere was evaluated. A total of 70 coffee samples of Arabica and Robusta coffee from different geographical origins were used as samples. NIR spectral data in the range of 1175.79 nm to 1651.222 nm were obtained using a portable NIR spectrometer equipped with an integrating sphere. The unsupervised classification was performed using PCA and supervised classification was conducted using the SIMCA method. The result of PCA shows that the samples were well clustered according to variety and geographical origin along the PC1 and PC2 axis both using original and preprocessed spectra. The SIMCA performed good results both for original and preprocessed spectral data, most of the testing sample set were properly classified to their corresponding classes.

Analysis of caffeine and chlorogenic acids content regarding the preparation method of coffee beverage

Abstract This research was focused on the evaluation of selected parameters of coffee quality, regarding the beverage preparation method, using high-performance liquid chromatography. Samples of Coffea arabica from South America were analyzed. For the preparation of the final beverage were used filtration and moka methods. All samples roasted at medium dark roasting level Full City ++, contained less than 5% of moisture. The values of pH and dry matter content did not show a significant difference. The lowest content of chlorogenic acid reached value (1.41 g·100 g−1) prepared from filtration and 1.49 g·100 g−1 prepared from moka method. The highest content of chlorogenic acid ranged from 2.94 g. 100 g−1 filtration method and 3.36 g. 100 g−1 moka. Similarly, caffeine content, showed lower values using the filtration method. Values ranged from 1.37 to 1.57% (filtration) and from 1.54 to 1.78% (moka). However, PCA didn’t show a significant difference.

Determining the impact of roasting degree, coffee to water ratio and brewing method on the sensory characteristics of cold brew Ugandan coffee

In today’s market, there is a growing demand for high-quality coffee with distinctive sensory characteristics, such a cold brew (CB) coffee. The objectives of this study were to determine the impact of a) degree of roasting, b) coffee to water ratio (C2WR), and c) brewing method on the sensory characteristics of CB coffee from d) various Ugandan coffee beans, both Robusta and Arabica. Four distinct coffee samples, sourced from lowland and mountainous regions in Uganda, were roasted and tested using a factorial design. A highly trained sensory panel evaluated the samples using 42 attributes. Results showed that all factors studied had an impact on most of the attributes. Not surprisingly, Robusta coffees generally had more bitter taste than Arabica coffees and the dark roast samples generally were more bitter than the medium roast coffees. Also, coffee samples that were brewed using a higher C2WR generally were more bitter than the coffees using a lower C2WR. However, although most of the main effects had a significant impact, their effects were mitigated by their interaction with other factors. For example, Medium roast Robusta that was slow-dripped with a high C2WR had a more bitter taste than the corresponding Arabica samples. However, when the Medium roast Robusta was steeped with a high C2WR it had a similar bitter intensity with the corresponding Arabica samples. Thus, although major impacts are critical, individual sample combinations must be considered when evaluating coffee samples for their impact on the sensory characteristics.

16-O-Methylated diterpenes in green Coffea arabica: ultra-high-performance liquid chromatography-tandem mass spectrometry method optimization and validation.

Coffee diterpenes are the main constituents of the coffee oil unsaponifiable fraction. The three most important diterpenes are cafestol, kahweol, and 16-O-methylcafestol (16-OMC), and they are produced, except for cafestol, only by plants of the Coffea genus. Recently, in addition to these three major diterpenes, another 16-O-methylated diterpene (16-O-methylkahweol: 16-OMK) has been identified and quantified, for the first time, in Robusta coffee. For many years, 16-OMC has been considered present exclusively in Robusta, and so it has been reputed an excellent authenticity marker for the presence of Robusta in coffee products. For its quantification, nuclear magnetic resonance (NMR) has proved very useful when compared with other methods. Quite recently, the detection of very low levels of the two 16-O-methylated diterpenes (16-OMD) 16-OMC and 16-OMK in roasted Arabica was reported. This finding makes the use of NMR methods in 16-OMD quantification in Arabica coffee particularly challenging in view of both the trace amounts of 16-OMD and the impossibility to discriminate between 16-OMC and 16-OMK. The ultra-high performance liquid chromatography mass spectrometry (UHPLC-MS) method, already used to detect 16-OMC and 16-OMK in Arabica roasted coffee, is then more suitable for quantitative analyses. Up to now however, no quantification of coffee 16-OMD via ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) has been carried out; this largely stimulated the present study. For the first time, a simple procedure for the quantitative detection of 16-OMD in Arabica coffee has been developed, and as far as 16-OMC is concerned, fully validated in terms of specificity, linearity, concentration range, limit of detection (LOD), limit of quantification (LOQ), and repeatability following the criteria specified in the EU Commission Decision 2002/675/EC. This method proved to be very specific and sensitive. In order to avoid the chemical complexity generated by the roasting process, the method was optimized and validated on several green Arabica samples from different geographical origins.

Characterization of Arabica and Robusta volatile coffees composition by reverse carrier gas headspace gas chromatography-mass spectrometry based on a statistical approach.

Nineteen samples of Arabica and 14 of Robusta coming from various plantation were analysed by dynamic headspace capillary gas chromatography-mass spectrometry to characterize the volatile fraction of green and roasted samples and the relationships of the same species with geographical origin. As concerns green beans, Arabica species appear characterized by high content of n-hexanol, furfural and amylformate, while Robusta species by greater content of ethylpyrazine, dimethylsulfone and 2-heptanone. Four variables, 4-methyl-2,3-dihydrofuran, n-hexanol, limonene and nonanal, appear involved in the characterization of the geographical origin of the analysed samples. The volatile fraction of the roasted Arabica samples, appear characterized by high content of pyridine, diacetyl, propylformate, acetone and 2,3-pentanedione, while Robusta samples by high content of methylbutyrate, 2,3-dimethylpyrazine and 3-hexanone. Considering geographical origin of the analysed samples, four compounds appear involved, in particular 2-butanone, methylbutyrate, methanol and ethylformate. Very accurate (error rate lower than 5%) rules to classify samples as Arabica or Robusta according to their compounds profile were developed.

PEMETAAN KARAKTERISTIK KIMIA BIJI KOPI ARABIKA GAYO DAN ROBUSTA GAYO

The distinctive aroma and taste of roasted coffee can be due to varietal differences in green coffee beans. The purpose of this research was to map the chemical characteristics of green coffee beans of Gayo arabica and Gayo robusta using principal component analysis (PCA) approach. Other analyses include pH using pH meter, total fats by Soxhlet method, total ash by gravimetric method, total protein by Kjeldahl method, total carbohydrates by difference, total soluble solids (TSS) by refractometer, organic acids composition by HPLC-UV/Vis, and total amino acids composition by UHPLC-PDAD. Six green coffee bean samples of Gayo arabica and Gayo robusta from different locations in Gayo, Aceh, as well as samples of arabica and robusta coffee beans each from plantation in West Java, Central Java and East Java (as comparators) were used in this study. The results showed the chemical characteristics of Gayo arabica and Gayo robusta could be mapped by PCA based on the concentrations of fats, organic acids and carbohydrates. The organic acid composition of Gayo arabica was associated with malic acid, succinic acid and citric acid, while Gayo robusta to acetic acid. The organic acids as well as TSS of the coffee beans could map Gayo arabica separately from Java arabica. Gayo arabica had higher organic acids, whereas Java arabica had higher TSS. Gayo robusta were characterized by higher fats, ash and total amino acids, but lower TSS than Java robusta. This study suggested the distinct characteristics of Gayo coffee beans to their corresponding coffee beans from Java.

Metabolomics fingerprint of Philippine coffee by SPME-GC-MS for geographical and varietal classification

Volatile metabolites of Philippine Arabica and Robusta coffee beans in both forms standard (not-eaten by the Asian palm civet) and civet coffee grown in different Philippine regions were identified using the hyphenated technique headspace-solid phase microextraction-gas chromatography-mass spectrometry. A great number of volatile metabolites with a wide variety of functional groups were extracted and forty-seven prominent compounds were identified.The volatile metabolomics (volatilomics) fingerprint of Arabica coffees considerably differed from Robusta coffee and geographical origin slightly altered the fingerprint profile of coffee samples. Chemometric analysis such as principal component analysis (PCA) displayed a good classification between Arabica and Robusta coffee samples. Although Arabica coffee samples from different geographical origins were clustered separately from each other, the proximity of clusters between Arabica coffee samples which could be classified into one large group, indicated their close similarity of headspace metabolites. The distinction between Arabica samples and Robusta coffees was attributed through the PCA to several key volatile metabolites, in particular, higher quantities of acetic acid, furfural, 5-methylfurfural, 2-formylpyrrole and maltol and lower concentrations of 4-ethylguaiacol and phenol. These discriminating metabolites could represent useful quality markers to differentiate Arabica from Robusta coffee. Results revealed that the headspace metabolites in coffee provide significant information on its inherent aroma quality. Also, the findings suggested that the overall quality of Philippine coffee is variety and region-specific.