Composition and properties of Indonesian palm civet coffee (Kopi Luwak) and Ethiopian civet coffee

Welfare and Management of Civets in Civet Coffee Tourism Plantations

Civet coffee is produced with coffee beans that have passed through the digestive tract of civets which are then processed for drinking. Outlets, known as civet coffee tourism plantations are popular tourist attractions in Bali, Indonesia. These outlets keep caged civets for public viewing and sell civet coffee. We assessed civet welfare in 29 civet coffee tourism plantations to assess husbandry factors, the five freedoms and body condition scores. We also assessed civet welfare in eight wildlife markets where civets are sourced for civet coffee tourism and calculated turnover of civets. We found 99 civets in civet coffee tourism plantations and 136 in markets, where. Annually between 400 and 800 civets are sold. Welfare standards do not meet the Indonesian laws and regulations. Diet, hygiene, presence of water and mobility affected body condition scores and no civet met all of the five freedoms. Enforcement of welfare and trade laws is needed to improve civet welfare, and to curb the illegal civet trade. Tourists frequenting civet coffee tourism plantations should be made aware of the low welfare standards to inform their choice about supporting this industry.

Thinking with Civets: The Role of Zoos in the Decolonisation of Animal Tourism

Civets belong to the family Viverridae, an ancient line of 'cat-like' animals. Despite their large geographic distribution across southeast Asia and parts of Africa, little scientific attention has been attributed to Viverrids or Viverrid-human relations. This paper applies the lens of civets to explore the tensive intersection between animal welfare, conservation, and colonialism within the tourism landscape. Through thinking with civets, this paper brings two forms of animal commodification into dialogue: (1) the management of civets in zoos around the globe and (2) the rising trend in civet coffee production and tourism in Asia. By qualitatively analysing the entanglements between colonialism, animal welfare, and conservation and how each impacts the lives and treatment of civets in tourism, this paper calls for enhanced reflexivity and thus the decolonisation of animal-based tourism. Suggestions are made on how zoos may progress towards the decolonisation of animal tourism, and the argument is made that zoos are well positioned and morally obligated to answer this call. By doing so, greater attention can be given to the animals whose lives are most affected by the global tourism landscape.

Metabolite Profiling of Premium Civet Luwak Bio-Transformed Coffee Compared with Conventional Coffee Types, as Analyzed Using Chemometric Tools

Luwak (civet) coffee is one of the most precious and exotic coffee commodities in the world. It has garnered an increasing reputation as the rarest and most expensive coffee, with an annual production. Many targeted analytical techniques have been reported for the discrimination of specialty coffee commodities, such as Luwak coffee, from other ordinary coffee. This study presents the first comparative metabolomics approach for Luwak coffee analysis compared to other coffee products, targeting secondary and aroma metabolites using nuclear magnetic resonance (NMR), gas chromatography (GC), or liquid chromatography (LC) coupled with mass spectrometry (MS). Chemometric modeling of these datasets showed significant classification among all samples and aided in identifying potential novel markers for Luwak coffee from other coffee samples. Markers have indicated that C. arabica was the source of Luwak coffee, with several new markers being identified, including kahweol, chlorogenic acid lactones, and elaidic acid. Aroma profiling using solid-phase micro-extraction (SPME) coupled with GC/MS revealed higher levels of guaiacol derivatives, pyrazines, and furans in roasted Luwak coffee compared with roasted C. arabica. Quantification of the major metabolites was attempted using NMR for Luwak coffee to enable future standardization. Lower levels of alkaloids (caffeine 2.85 µg/mg, trigonelline 0.14 µg/mg, and xanthine 0.03 µg/mg) were detected, compared with C. arabica. Other metabolites that were quantified in civet coffee included kahweol and difurfuryl ether at 1.37 and 0.15 µg/mg, respectively.

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.

Digested Civet Coffee Beans (Kopi Luwak)-An Unfortunate Trend in Specialty Coffee Caused by Mislabeling of Coffea liberica?

In the context of animal protection, the trend of digested coffees such as Kopi Luwak produced by civet cats in captivity should not be endorsed. Previous studies on such coffees may have been flawed by sample selection and misclassification. As wild civets may prefer Coffea liberica beans, due to their higher sugar content, the chemical differences may be caused by the Coffea species difference combined with a careful selection of ripe, defect-free cherries by the animals, rather than changes caused by digestion. This may also explain the observed differences between Kopi Luwak from wild civets (mainly C. liberica) compared to the one from animals in captivity (typically fed with C. arabica and/or C. canephora).

Between attraction and aversion: How designers can use the concept of disgust to influence food consumption

Disgust is a strong emotion of aversion. In the context of food, it is often referred to as a guardian of the mouth, preventing close contact with pathogens and the accidental consumption of poisons. However, disgust can also create a certain level of attraction and be part of positive experiences, even in the context of food. In this article, we discuss different ways of using disgust to influence eating behaviour and contribute to healthier food consumption. We outline ten different bridging concepts accompanied by various design exemplars on how to use disgust in the context of critical food design. In addition, we present four different lenses that can help to refine the design concepts.

Metabolite profiles and antidiabetic activity of the green beans of Luwak (civet) coffees

Metabolite profiles of green beans (the caged and the wild) Luwak (civet) coffees were evaluated by NMR techniques combined with chemometrics. The bioactivities of the green coffee beans were examined with antioxidant tests and an alpha-glucosidase inhibitory assay. Both are invitro tests related to the antidiabetic properties. Our results showed the civet coffees possessed unique metabolomes and were different from the regular arabica coffee. Both civet coffees were characterized by higher concentrations of alanine, citrate, lactate, malate, and trigonelline. Lactate and lipids were found as the most important compounds discriminating the caged civet coffee from the wild civet coffee. Bioactivity assays exhibited the antidiabetic activities of the civet coffees were better than the activity of the regular coffee. These results suggested that the civet coffees are promising functional foods reducing the diabetes risk. It is the first report evaluating metabolite profiles of both civet coffees using ¹H NMR-based metabolomics.

Potential applications of by-products from the coffee industry in polymer technology - Current state and perspectives

Coffee is one of the most popular beverages in the world, and its popularity is continuously growing, which can be expressed by almost doubling production over the last three decades. Cultivation, processing, roasting, and brewing coffee are known for many years. These processes generate significant amounts of by-products since coffee bean stands for around 50% of the coffee cherry. Therefore, considering the current pro-ecological trends, it is essential to develop the utilization methods for the other 50% of the coffee cherry. Among the possibilities, much attention is drawn to polymer chemistry and technology. This industry branch may efficiently consume different types of lignocellulosic materials to use them as fillers for polymer composites or as intermediate sources of particular chemical compounds. Moreover, due to their chemical composition, coffee industry by-products may be used as additives modifying the oxidation resistance, antimicrobial, or antifungal properties of polymeric materials. These issues should be considered especially important in the case of biodegradable polymers, whose popularity is growing over the last years. This paper summarizes the literature reports related to the generation and composition of the coffee industry by-products, as well as the attempts of their incorporation into polymer technology. Moreover, potential directions of research based on the possibilities offered by the coffee industry by-products are presented.

Ecological traps and boosters of ixodid ticks: The differing ecological roles of two sympatric introduced mammals

The raccoon (Procyon lotor) and masked palm civet (Paguma larvata) are introduced species in Japan and have become abundant in human-inhabited environments. We surveyed tick infestations and tick ingestion by introduced raccoons and masked palm civets captured in Hayama, Kanagawa Prefecture, Japan between November 2018 and January 2020. We collected ticks from the body surface of animals and tick capitula from the gastrointestinal contents. We collected 18,357 ticks identified as Haemaphysalis flava, Haemaphysalis megaspinosa, Haemaphysalis longicornis, Ixodes ovatus, Ixodes tanuki, and Amblyomma testudinarium from 58 of 60 raccoons and 152 ticks, identified as H. flava and I. tanuki, from 16 of 41 masked palm civets. Furthermore, we obtained 16 capitula from 12 % of raccoons and 106 capitula from 63 % of masked palm civets. Raccoons harbored a greater number of ticks (all stages of H. flava and adult I. tanuki) compared with masked palmed civets, whereas the latter species ingested a greater number of nymphal and larval ticks. The results of this study extend our understanding of the ecological roles of two introduced wildlife species. The raccoon may act as an ecological booster, thereby increasing the success rate of bloodmeals and reproduction in ticks. In contrast, the masked palm civet may act as an ecological trap by effectively grooming to remove ticks and prevent bloodmeals.

New trends in specialty coffees - "the digested coffees"

Specialty coffee has gained immense popularity for its unique flavor and improved quality. There are large varieties of coffee trending every day due to the widened demand. Still, specialty coffee holds its place for its distinct processing inside the animal digestive system. Specialty coffees are also considered the most expensive due to coffee varieties with novelty in processing which leads to limited availability and less productivity. The digested coffee's uniqueness and rarity led to higher consumer demand, which paved the way for animal abuse in captivity and the production of fake authenticity to tackle the increased market requirement. In the context of coffee processing through conventional methods, the application of enzymes and microbes has brought about an improvement in coffee fermentation. Much research has been focused on the isolation of microbial cultures from the animal excreta and gastrointestinal tract. This review emphasizes the types of specialty coffee, its uniqueness compared to the traditional varieties, the bio-processing method of specialty coffee inside the animal gut and its taste profile.

Isolation of microorganisms from the feces of ring-tailed coati related to the production of "misha coffee" in the central forest of Peru and evaluation of some features of technological importance

A diversity of yeasts and lactic bacteria were isolated from the feces of ring-tailed coaties bred in captivity and related to the production of "misha coffee". Isolation of yeasts was carried out using oxytetracycline-glucose-yeast extract agar containing 100 mg/L oxytetracycline and, lactic bacteria using de Man-Rogosa and Sharpe agar containing 20 mg/L of vancomicin. Then, isolates were biochemically analysed using API strips (ID 32C for yeasts and 50CHL for lactic bacteria) followed by 16S and 26S rRNA gene sequencing. Among the yeasts, Debaryomyces hansenii, Pichia kluyveri, Pichia kudriavzevii, and Candida sorboxilosa were the most frequent, whereas Weissella cibaria, Weissella paramesenteroides, Enterococcus thailandicus and Enterococcus faecalis were the most important lactic bacteria. Cultivation of the isolated yeasts under agitated conditions, showed that Pichia kluyveri LBFT.Lev3 (0.15 ± 0.01 h^-1) and Pichia kudriavzevii LBTF.Lev7 (0.14 ± 0.01 h^-1) had higher specific growth rates than Debaryomyces hansenii LBFT.Lev9 (0.09 ± 0.01 h^-1), whereas cultivation of lactic bacteria under static fashion showed that Weisella paramesenteroides LBTF.Bal2 (0.16 ± 0.01 h^-1) and Weisella cibaria LBTF.Bal3 (0.18 ± 0.01 h^-1) had better growth than Enterococcus thailandicus LBTF.Bal1 (0.1 ± 0.015 h^-1) and Enterococcus faecalis LBTF.Bal7 (0.14 ± 0.01 h^-1). Additionally, evaluation of pectinolytic activity revealed that Pichia kudriavzevii LBTF.Lev7 and Debaryomyces hansenii LBFT.Lev9 were able to use pectin as carbon source for their growth. On the other hand, W. cibaria LBTF.Bal3, E. thailandicus LBTF.Bal1 and W. paramesenteroides LBTF.Bal2 showed inhibitory activity against S. mutans ATCC 35668, B. subtilis subsp. spizizenii ATCC 6633 and Staph. epidermidis ATCC 14990. Results of this study are useful for the search of potential application of the isolated yeasts and lactic bacteria in coffee and other food fermentations.

Discrimination of civet coffee using visible spectroscopy

Civet coffee is considered as highly marketable and rare. This specialty coffee has a special flavor and higher price relative to regular coffee, and it is restricted in supply. Establishing a straightforward and efficient approach to distinguish Civet coffee for quality; likewise, consumer protection is fundamental. This study utilized visible spectroscopy as a non-destructive and quick technique to obtain the absorbance, ranging from 450 nm to 650 nm, of the civet coffee and non-civet coffee samples. Overall, 160 samples were analyzed, and the total spectra accumulated was 960. The data gathered from the first 120 samples were fed to the classification learner application and were used as a training data set. The remaining samples were used for testing the classification algorithm. The study shows that civet coffee bean samples have lower absorbance values in visible spectra than non-civet coffee bean samples. The process yields 96.7 % to 100 % classification scores for quadratic discriminant analysis and logistic regression. Among the two classification algorithms, logistic regression generated the fastest training time of 14.050 seconds. The application of visible spectroscopy combined with data mining algorithms is effective in discriminating civet coffee from non-civet coffee.

Gluconobacter dominates the gut microbiome of the Asian palm civet Paradoxurus hermaphroditus that produces kopi luwak

Coffee beans derived from feces of the civet cat are used to brew coffee known as kopi luwak (the Indonesian words for coffee and palm civet, respectively), which is one of the most expensive coffees in the world owing to its limited supply and strong market demand. Recent metabolomics studies have revealed that kopi luwak metabolites differ from metabolites found in other coffee beans. To produce kopi luwak, coffee beans are first eaten by civet cats. It has been proposed that fermentation inside the civet cat digestive tract may contribute to the distinctively smooth flavor of kopi luwak, but the biological basis has not been determined. Therefore, we characterized the microbiome of civet cat feces using 16S rRNA gene sequences to determine the bacterial taxa that may influence fermentation processes related to kopi luwak. Moreover, we compared this fecal microbiome with that of 14 other animals, revealing that Gluconobacter is a genus that is, uniquely found in feces of the civet cat. We also found that Gluconobacter species have a large number of cell motility genes, which may encode flagellar proteins allowing colonization of the civet gut. In addition, genes encoding enzymes involved in the metabolism of hydrogen sulfide and sulfur-containing amino acids were over-represented in Gluconobacter. These genes may contribute to the fermentation of coffee beans in the digestive tract of civet cats.

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

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.

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.

Microbiome-Guided Exploration of the Microbial Assemblage of the Exotic Beverage "Insect Tea" Native to Southwestern China

Insect tea is a unique beverage that is native to Southwestern China and traditionally produced by local farmers in an elaborate process. It consists of insect larvae excrements that are commonly obtained from meal moths (Pyralis farinalis Linnaeus 1758) reared on a specific plant-based diet. We have reconstructed the whole production process under laboratory conditions in order to obtain microbiome-level insights into this uncommon beverage and to trace back the origin of the prevalent bacteria in the final product. The bacterial community composition was specific for each production stage, with a high proportion of Streptomycetacea, Pseudonocaridaceae, Enterococcaceae, and Enterobacteriaceae in the insect tea. A large proportion of the constituents was traced back to the producing insect (13.2%) and its excrements (43.8%), while the initial plant-based substrate for tea production was found to contribute only 0.6% of the traceable bacteria in the final product. Moreover, an enrichment of Enterobactericeae was observed during the analyzed process steps and verified with complementary analyses. The cultivation experiments indicated a high occurrence of viable bacteria in the tea at 2.7 × 105 ± 1.2 × 105 cfu g-1. The isolated bacteria included Bordetella petrii and Enterococcus spp. that were recovered from a commercial product. By implementing an integrative approach, the insect tea was shown to harbor a species-rich bacterial community that can be traced back to certain plant and insect microbiome constituents from distinct production steps. Moreover, the microbial profile of the insect tea was found to be unique for a food product so far and contained several bacterial groups that are considered from the current perspective as food contaminants or yet unreported in other beverages. Due to the high number of viable bacteria, the tea harbors a so far undescribed dynamic component that might have implications for human health.

Review: Potensi mikrobial selulase, xilanase, dan protease dalam fermentasi kopi luwak (Paradoxurus hermaphroditus) secara in vitro

Kopi luwak adalah kopi bernilai tinggi dengan aroma dan rasa khas, yang dihasilkan dari biji kopi yang telah difermentasi sebagian dalam sistem pencernaan luwak (Paradoxurus hermaprodithus). Tingginya permintaan kopi ini dan produksi alami yang unik berimplikasi pada praktek pemaksaan dan penyiksaan hewan luwak, serta adanya kontroversi status kehalalan produk. Fermentasi in vitro menggunakan selulase, xilanase, dan protease yang diisolasi dari kotoran luwak tampaknya dapat menjadi alternatif proses untuk menghindari masalah pelecehan hewan, menjamin kehalalan produk serta memastikan keberlanjutan produksi kopi luwak. Kajian ini bertujuan untuk meringkas dan mensintesis peran tiga enzim ini (selulase, xilanase, dan protease) dalam fermentasi in vitro kopi luwak dan pengaruhnya pada karakteristik kimia dan sensori berdasarkan hasil-hasil penelitian terbaru. Hasil kajian menunjukkan bahwa fermentasi in vitro menggunakan selulase, xilanase, dan protease. biji kopi menghasilkan karakteristik kimia dan sensorik yang sama dengan yang dihasilkan melalui proses alami yang melibatkan hewan luwak.

Farm to Consumer: Factors Affecting the Organoleptic Characteristics of Coffee. II: Postharvest Processing Factors

The production and consumption of coffee are increasing despite the roadblocks to its agriculture and global trade. The unique, refreshing, and stimulating final cupping quality of coffee is the only reason for this rising production and consumption. Coffee quality is a multifaceted trait and is inevitably influenced by the way it is successively processed after harvesting. Reportedly, 60% of the quality attributes of coffee are governed by postharvest processing. The current review elaborates and establishes for the first time the relationship between different methods of postharvest processing of coffee and its varying organoleptic and sensory quality attributes. In view of the proven significance of each processing step, this review has been subdivided into three sections, secondary processing, primary processing, and postprocessing variables. Secondary processing addresses the immediate processing steps on the farm after harvest and storage before roasting. The primary processing section adheres specifically to roasting, grinding and brewing/extraction, topics which have been technically addressed more than any others in the literature and by industry. The postprocessing attribute section deals generally with interaction of the consumer with products of different visual appearance. Finally, there are still some bottlenecks which need to be addressed, not only to completely understand the relationship of varying postharvest processing methods with varying in-cup quality attributes, but also to devise the next generation of coffee processing technologies.

Detection of micro-toxic elements in commercial coffee brands using optimized dual-pulsed laser-induced spectral analysis spectrometry

A fast detection system based on dual-pulsed laser-induced breakdown spectroscopy (DP-LIBS) was successfully developed and optimized for the estimation of micro-toxic element contents in commercial coffee brands to monitor pollution and ensure food safety. A series of 13 various coffee brands were quantitatively analyzed in this study utilizing DP-LIBS and a standard analytical technique like inductively coupled plasma/optical emission spectrometry (ICP-OES). The micro-toxic elements, such as aluminum (Al), lead (Pb), zinc (Zn), and chromium (Cr), that exist in the coffee brands were exactly identified. We prepared standard matrices in a known concentration in the coffee sample to draw the standard calibration curves for each element, as well as by utilizing a tactic based on the intense line emission of the element of interest as a quantitative analysis. The analytical routines were approved under the expectations that the plasma created by the dual-pulsed lasers was in local thermodynamic equilibrium (LTE) and was optically thin. We investigated the influence of different parametric dependence studies to enhance our DP-LIBS detection sensitivity. Furthermore, the precision of our DP-LIBS data for determining the concentration of micro-toxic elements present in coffee samples was validated via the ICP-OES technique. The results achieved by the DP-LIBS technique were in full agreement with the ICP-OES results. In addition, the estimated limit of detection of our DP-LIB spectrometer for Al, Pb, Zn, and Cr were 105.13±07, 90.17±12, 83.58±15, and 68.78±09  μg L^-1, respectively. The suggested protocols demonstrated the excellent benefits of the DP-LIBS for the detection of micro-toxic elements existing in coffee and for checking the purity and quality of food products.

Identification of Volatile Compounds and Selection of Discriminant Markers for Elephant Dung Coffee Using Static Headspace Gas Chromatography-Mass Spectrometry and Chemometrics

Elephant dung coffee (Black Ivory Coffee) is a unique Thai coffee produced from Arabica coffee cherries consumed by Asian elephants and collected from their feces. In this work, elephant dung coffee and controls were analyzed using static headspace gas chromatography hyphenated with mass spectrometry (SHS GC-MS), and chemometric approaches were applied for multivariate analysis and the selection of marker compounds that are characteristic of the coffee. Seventy-eight volatile compounds belonging to 13 chemical classes were tentatively identified, including six alcohols, five aldehydes, one carboxylic acid, three esters, 17 furans, one furanone, 13 ketones, two oxazoles, four phenolic compounds, 14 pyrazines, one pyridine, eight pyrroles and three sulfur-containing compounds. Moreover, four potential discriminant markers of elephant dung coffee, including 3-methyl-1-butanol, 2-methyl-1-butanol, 2-furfurylfuran and 3-penten-2-one were established. The proposed method may be useful for elephant dung coffee authentication and quality control.

The Use of Partial Least Square Regression and Spectral Data in UV-Visible Region for Quantification of Adulteration in Indonesian Palm Civet Coffee

Asian palm civet coffee or kopi luwak (Indonesian words for coffee and palm civet) is well known as the world's priciest and rarest coffee. To protect the authenticity of luwak coffee and protect consumer from luwak coffee adulteration, it is very important to develop a robust and simple method for determining the adulteration of luwak coffee. In this research, the use of UV-Visible spectra combined with PLSR was evaluated to establish rapid and simple methods for quantification of adulteration in luwak-arabica coffee blend. Several preprocessing methods were tested and the results show that most of the preprocessing spectra were effective in improving the quality of calibration models with the best PLS calibration model selected for Savitzky-Golay smoothing spectra which had the lowest RMSECV (0.039) and highest RPD_cal value (4.64). Using this PLS model, a prediction for quantification of luwak content was calculated and resulted in satisfactory prediction performance with high both RPD _p and RER values.

Modulation of coffee aroma via the fermentation of green coffee beans with Rhizopus oligosporus: I. Green coffee

Modulation of coffee aroma via the biotransformation/fermentation of different coffee matrices during post-harvest remains sparingly explored despite some studies showing their positive impacts on coffee aroma. Therefore, this is an unprecedented study aimed at modulating coffee aroma via the fermentation of green coffee beans with a food-grade fungus Rhizopus oligosporus. The objective of part I of this two-part study was to characterize the volatile and non-volatile profiles of green coffee beans after fermentation. Proteolysis during fermentation resulted in 1.5-fold increase in the concentrations of proline and aspartic acid which exhibited high Maillard reactivity. Extensive degradation of ferulic and caffeic acids led to 2-fold increase in the total concentrations of volatile phenolic derivatives. 36% of the total volatiles detected in fermented green coffee beans were generated during fermentation. Hence, the work presented demonstrated that R. oligosporus fermentation of green coffee beans could induce modification of the aroma precursors of green coffees.

Quantification of coffee blends for authentication of Asian palm civet coffee (Kopi Luwak) via metabolomics: A proof of concept

Asian palm civet coffee (Kopi Luwak), an animal-digested coffee with an exotic feature, carries a notorious reputation of being the rarest and most expensive coffee beverage in the world. Considering that illegal mixture of cheap coffee into civet coffee is a growing concern among consumers, we evaluated the use of metabolomics approach and orthogonal projection to latent structures (OPLS) prediction technique to quantify the degree of coffee adulteration. Two prediction sets, consisting of certified and commercial coffee, were made from a blend of civet and regular coffee with eleven mixing percentages. The prediction model exhibited accurate estimation of coffee blend percentage thus, successfully validating the prediction and quantification of the mixing composition of known-unknown samples. This work highlighted proof of concept of metabolomics application to predict degree of coffee adulteration by determining the civet coffee fraction in blends.

Application of gas chromatography/flame ionization detector-based metabolite fingerprinting for authentication of Asian palm civet coffee (Kopi Luwak)

Development of authenticity screening for Asian palm civet coffee, the world-renowned priciest coffee, was previously reported using metabolite profiling through gas chromatography/mass spectrometry (GC/MS). However, a major drawback of this approach is the high cost of the instrument and maintenance. Therefore, an alternative method is needed for quality and authenticity evaluation of civet coffee. A rapid, reliable and cost-effective analysis employing a universal detector, GC coupled with flame ionization detector (FID), and metabolite fingerprinting has been established for discrimination analysis of 37 commercial and non-commercial coffee beans extracts. gas chromatography/flame ionization detector (GC/FID) provided higher sensitivity over a similar range of detected compounds than GC/MS. In combination with multivariate analysis, GC/FID could successfully reproduce quality prediction from GC/MS for differentiation of commercial civet coffee, regular coffee and coffee blend with 50 wt % civet coffee content without prior metabolite details. Our study demonstrated that GC/FID-based metabolite fingerprinting can be effectively actualized as an alternative method for coffee authenticity screening in industries.

Coffee fermentation and flavor--An intricate and delicate relationship

The relationship between coffee fermentation and coffee aroma is intricate and delicate at which the coffee aroma profile is easily impacted by the fermentation process during coffee processing. However, as the fermentation process in coffee processing is conducted mainly for mucilage removal, its impacts on coffee aroma profile are usually neglected. Therefore, this review serves to summarize the available literature on the impacts of fermentation in coffee processing on coffee aroma as well as other unconventional avenues where fermentation is employed for coffee aroma modulation. Studies have noted that proper control over the fermentation process imparts desirable attributes and prevents undesirable fermentation which generates off-flavors. Other unconventional avenues in which fermentation is employed for aroma modulation include digestive bioprocessing and the fermentation of coffee extracts and green coffee beans. The latter is an area that should be explored further with appropriate microorganisms given its potential for coffee aroma modulation.

Selection of discriminant markers for authentication of Asian palm civet coffee (Kopi Luwak): a metabolomics approach

Kopi Luwak, an exotic Indonesian coffee, is made from coffee berries that have been eaten by the Asian palm civet ( Paradoxurus hermaphroditus ). Despite being known as the world's most expensive coffee, there is no reliable, standardized method for determining its authenticity. GC-MS-based multimarker profiling was employed to explore significant metabolites as discriminant markers for authentication. Extracts of 21 coffee beans ( Coffea arabica and Coffea canephora ) from three cultivation areas were analyzed and subjected to multivariate analyses, principal component analysis, and orthogonal projection to latent structures discriminant analysis. Citric acid, malic acid, and the inositol/pyroglutamic acid ratio were selected for further verification by evaluating their differentiating abilities against various commercial coffee products. The markers demonstrated potential application in the differentiation of original, fake Kopi Luwak, regular coffee, and coffee blend samples with 50 wt % Kopi Luwak content. This is the first report to address the selection and successful validation of discriminant markers for the authentication of Kopi Luwak.

Gas chromatography/olfactometry and electronic nose analyses of retronasal aroma of espresso and correlation with sensory evaluation by an artificial neural network

To develop a method for evaluating and designing the retronasal aroma of espresso, sensory evaluation data was correlated with data obtained from gas chromatography/olfactometry (GC/O, CharmAnalysis™) and from an electronic nose system αFOX4000 (E-nose). The volatile compounds of various kinds of espresso (arabica coffee beans from 6 production countries: Brazil, Ethiopia, Guatemala, Colombia, Indonesia, and Tanzania; 3 roasting degrees for each country: L values, 18, 23, and 26) were collected with a retronasal aroma simulator (RAS) and examined by GC/O and E-nose. In addition, sensory descriptive analysis using a 7-point scale for RAS effluent gas was performed by 5 trained flavorists using sensory descriptors selected based on the frequency in use and coefficient of correlation. The charm values of 10 odor descriptions obtained from GC/O analysis exhibited the significant (P < 0.05) differences among both roasting degrees and origins. Also, linear discriminant analysis (LDA) on the E-nose-sensor resistances and factor analysis on the sensory evaluation scores showed that the differences of aroma characteristics among the roasting degrees were larger than those among the origins. Based on an artificial neural network (ANN) model applied to the data from GC/O analyses and sensory evaluations, the perceptual factor of the RAS aroma was predicted to be mainly affected by sweet-caramel, smoke-roast, and acidic odors. Also, 3 metal oxide semiconductor sensors (LY2/Gh, P30/1, and T40/1) of E-nose were selected for analyses of RAS aroma and correlated with the sensory descriptive scores by the ANN to support sensory evaluation.