Arabica Coffee Beans Research Articles

The Effect of Temperature and Duration Roasting of the Physical Characteristics of Arabica Coffee

This study aims to determine the effect of temperature and roasting time on changes in physical characteristics of arabica coffee beans. Rotary type mechanical coffee roaster equipment equipped with a digital temperature measuring device to measure the roasting temperature. The heat source used is from the gas stove with the inner surface temperature of the coffee bean roaster cinder being kept constant. Arabica dry coffee as much as 500 grams with 14 % moisture content is put into the roasting device which has been heated at the desired temperature. The roasting is done by repetition twice for each temperature which is 165 °C, 175 °C, 185 °C and 195 °C with variations in the average length of time ie 35 minutes, 29 minutes, 25 minutes and 23 minutes. The results showed that the temperature and roasting time had an effect on the physical characteristics of the coffee beans, especially the very real color changes and also the changes in the average moisture content of coffee beans were 1.82 %, 1.43 %, 1.12 % respectively. and 0.94 %. Keywords: Arabica coffee, temperature, roasting time, physical characteristics

ANALYSIS OF FERULIC ACID IN ARABICA COFFEE BEAN (COFFEA ARABICA L.) USING SOLID PHASE EXTRACTION–HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

Objective: The purpose of this research is quantitatively analyzing of ferulic acid in the Arabica coffee bean extract from three samples with different regions (Garut, Pangalengan, Tasikmalaya, West Java Indonesia) using Solid Phase Extraction-High Performance Liquid Chromatography (SPE-HPLC) method which is validated.
 Methods: The analysis method used reversed phase HPLC with an Enduro C 18 G (250 mm × 4.6 mm) column and detector UV 312 nm, with a mobile phase of methanol and water containing 1% (v/v) of acetic acid (42:58) at a flow rate of 1.0 ml/min and validation method was examined in linearity, Limit of Detection (LOD), Limit of Quantification (LOQ), precision, and accuracy.
 Results: The results showed that the precision of retention was 8.853 min, correlation coefficient (R) was 0.9996, and the recovery was 96.909%. The quantitative analysis of ferulic acid content in the extract of coffee from thus samples of three different regions were 0.0385%, 0.0169% and 0.0076%, respectively.
 Conclusion: The analytical method was meet the validation criteria. Ferulic acid levels results from the extraction of the digestion process and pretreatment methods of Solid Phase Extraction (SPE) is 0.0385% from Garut area, 0.0169% from Pangalengan area and 0.0076% from Tasikmalaya area.

Integration of Gas Sensors as an Exhaust Gas Monitoring Device from Green Roasting Process of Various Coffee Beans

The exhaust gas monitoring system in the coffee roasting process continues to be developed considering the need for more complex roasting coffee beans information. The integrated gas sensor is designed by utilizing a microcontroller controller to see the exhaust gas during the roasting process. The exhaust gas produced during the roasting process is monitored by integrating sensors device to measure exhaust gases (CO, CO2, NOx and SO2). Furthermore, measurements were made by monitoring exhaust gas during roasting of Arabica, Liberica and Robusta coffee beans from Jambi province. The results showed that the total CO concentration in Liberica coffee was 2,121 ppm, Robusta 1,930 ppm and Arabica 1,535 ppm while for CO2 was Liberica 21.3 ppm; Robusta is 22.2 ppm; Arabica is 22.4 ppm, and for NOx is Liberica 303 ppm; Robusta 304 ppm; Arabica is 287 ppm, and the SO2 content for all types of coffee is 0 ppm. The highest exhaust gas concentration occurs after roasting lasts > 20 minutes and at a temperature of 210 - 230°C. It concluded that the integrated gas sensor can be used for the measurement of exhaust gas in the process of coffee beans roasting with the results of measurement of CO exhaust concentration in Liberica coffee is higher than Robusta and Arabica coffee beans.

Different Chemical Compound Profiles of Indonesian Coffee Beans as Studied Chromatography/Mass Spectrometry

Coffee is a favourite beverage worldwide, with all of its benefits. The taste and flavour of coffee depending on the chemical components of the coffee. And the presence of chemicals in the coffee ground depends on the original tree as well as on processing. In this report, some volatiles from ground and brewed coffee beans of Robusta, Arabica, and peaberry coffee beans were extracted to be described after chemical analysis. Mainly gas chromatography/mass spectrometry methods were the main spectroscopy utilized to obtain chemistry information that was taken from hot brewed coffees. The result showed that peaberry coffee beans were very rich in components compared to others. Arabica coffee beans also had stronger in taste and flavour compared to robusta as seen from the profile compositions of chloroform and n-hexane extracts. Better processing would also be suggested for each type of coffee beans.

Sensory Attributes of Cold Brew Coffee Products at Various Resting Time After Roasting Process


 
 
 The quality of the brewed coffee depends on various factors. Resting time of roasted coffee beans is one of the processes that can affect the sensory charac- teristics of coffee brew. During resting the reduction of CO2 gas level may change and give significan effect on sensory quality of coffee. This study aims to determine the dominant sensory characteristics that can be used as quality parameters of cold brew coffee products at various resting times after roasting. The cold brew coffee product was brewed from roasted Arabica coffee beans with various resting time (0, 1, 3, 5, 7, and 9 days). Projective Mapping (Napping) sensory analysis method was used in this study. The samples were tested by 75 untrained panelists (naive panelists). Multiple Factor Analysis was used to obtain the cold brew coffee sample position configuration. The results of the analysis showed that panelists were able to differen- tiate the characteristic of sensory attributes each sample. The aroma and flavor are the main attributes that can differentiate the characteristics of each sample. From the napping method, the results obtained in the form of individual factor map and preference mapping showed that the sample resting time 1 and 3 days after roasting were assessed by the panelists as closest to the control sample (0 days). In summary, the resting time treatment of roasted coffee beans have a significant effect on the sensory characteristics of cold brew coffee products. This is proofed by changes of aroma, flavor, and aftertaste during certain period of resting time.
 
 

Correlation between the composition of green Arabica coffee beans and the sensory quality of coffee brews

This research aimed to correlate the composition of green Arabica coffee beans with the sensory quality coffee brews. The chemical composition of green Arabica coffee bean (66 samples) from three coffee quality contests was analyzed by near-infrared spectroscopy. Coffee brews with lower quality scores were correlated with high levels of caffeine, protein, chlorogenic acids and total titratable acidity (TTA) in the green coffee beans. High sucrose/TTA and cafestol/kahweol ratios in the green coffee beans were usually associated with higher scores for the coffee brews. By multivariate analysis techniques, the samples were separated into groups according to production years indicating a strong influence of the environmental conditions on the chemical composition. The profile of the composition of the crude coffee can be indicative of the sensory quality of the coffee brews, relevant information for producers and industry since the green beans are the material used for trading and purchasing coffee.

Characterization and Evaluation of Physical and Mechanical Properties of Un hulled Arabica Coffee Bean

This work was carried out to characterize the physical and mechanical properties of unhulled arabica coffee bean. The results of this work found that at moisture content of 18.76 ± 0.19 % wb, the average length, width, thickness, geometric diameter and surface area of unhulled coffee bean ranged from 12.04 ± 1.06 mm, 8.24 ± 0.45 mm, 4.99± 0.34 mm, 7.90 ± 0.38 mm and 196.44 ± 19.09 mm2 respectively. The average mass and volume ranged from 0.21 ± 0.06 g and 0.21 ± 0.06 cm3 respectively. The average particle density, bulk density and sphericity ranged from 1.00 ± 0.02 g/cm3, 0.40 ± 0.01 g/cm3 and 0.66 ± 0.04% respectively. The average porosity, aspect ratio, and shell content ranged from 60.16 ± 1.09 %, 68.88 ± 6.38% and 16.55 ± 5.70% respectively. The average hardness and fracturability ranged from 12.34 ± 1.28 gf and 2.45 ± 0.08 gf respectively. Regarding the angle of repose on the surface of stainless steel, aluminum, acrylic, and plywood results showed that the average emptying angle of repose ranged from 26.88 ± 3.67°, 29.44 ± 3.35°, 30.01 ± 4.83° and 40.0° ± 7.00° respectively, and the average filling angle of repose ranged from 32.02 ± 2.880°. Concerning friction, results of measurement indicated that average static friction of stainless steel, aluminum, acrylic, and plywood ranged from 0.36 ± 0.02, 0.40 ± 0.03, 0.38 ± 0.04 and 0.45 ±0.03 respectively. The highest emptying angle of repose occurred on the surface of plywood inversely of that was occurring on the surface of stainless steel. There was a positive relationship between the angle of repose and the static friction.

FUNGAL INFECTION OF STORED ARABICA COFFEE (Coffea arabica) BEANS IN SOUTH SULAWESI PROVINCE, INDONESIA

Indonesia is the world’s fourth-largest coffee producer after Brazil, Vietnam, and Columbia, in which one of its well-known coffee originates from the Toraja region, South Sulawesi. As such, Indonesia has to compete with these countries in producing good quality coffee beans. Consequently, this research aimed (a) to obtain information on the postharvest handling methods of Arabica coffee (C. arabica) beans in Tana Toraja, North Toraja Regencies, and Makassar Municipality, Indonesia, and (b) to investigate the occurrence of fungi (including ochratoxin A producing fungi) in stored Arabica coffee beans collected from various stages of the delivery chain. The data collection process included surveys, interviews, and sample collections conducted in May and July 2016 at each level of the delivery chain. The moisture content (MC) and the physical quality of the beans were also measured to determine its quality. Sixty-four (64) coffee bean samples were collected, consisting of 27 samples from the farmers, 15 samples from the collectors, 13 samples from the traders, and 9 samples from the exporters. The results showed that the moisture contents of coffee beans collected from the farmers and bean collectors (42.5%) were significantly higher than the maximum tolerable limit determined by the Indonesian National Standard (SNI) (13%), while the MC of the beans from the traders and exporters (9.7-10.9%) was significantly lower. Based on the total defective values, coffee beans from the farmers had more diverse grades (1-6) than those at other levels. Penicillium citrinum was the dominant fungus found in those beans collected from the farmers, collectors, and traders, while Aspergillus niger was the dominant fungus found in those beans from the exporters. At trader level, 46% of the samples were infected by Aspergillus ochraceus and A. niger, which are known as ochratoxin A (OTA) producing fungi. At exporter level, 44% of the samples were infected by A. ochraceus, while 78% of the samples were infected by A. niger. Thus, the postharvest handling methods conducted especially by farmers and collectors of Arabica coffee beans should be improved to reduce the moisture content and to increase the grade quality of the coffee beans.

HPLC Quantification and MS/NMR Confirmation of Javamide-I/-II in Arabica and Robusta Coffee Beans from Different Regions for Finding Better Bean Sources for Javamide-I/-II

HPLC Quantification and MS/NMR Confirmation of Javamide-I/-II in Arabica and Robusta Coffee Beans from Different Regions for Finding Better Bean Sources for Javamide-I/-II

Effect of mild roasting on Arabica and Robusta coffee beans contamination with polycyclic aromatic hydrocarbons

The aim of this research was to establish the effect of mild roasting on coffee beans contamination level by polycyclic aromatic hydrocarbons (PAHs). The materials investigated were green Arabica and Robusta coffee beans imported from different countries, as well as those already roasted. The experiment was carried out in a coffee-roasting plant, with the use of an electric coffee roaster, at the temperature of 125–135 °C for 25–26 min. PAHs analysis was conducted by means of high-performance liquid chromatography with fluorescence and diode array detectors (HPLC-FLD/DAD). Results had been verified by means of gas chromatography with mass spectrometry. Contamination level for 19 PAHs, 15 of which were heavy PAHs included on the list of European Union Scientific Committee in Food, varied from 4.29 to 16.17 µg/kg in roasted coffee beans, whereas in green coffee beans varied from 8.66 to 76.63 µg/kg. The results of statistical analysis showed that the contamination level in roasted coffee beans was significantly lower than that in green beans. The applied parameters of roasting did not lead to the occurrence of conditions in which PAHs, especially heavy ones, would possibly be formed. On the contrary, the roasting process itself had significantly reduced the PAHs content in the final product. The reason for this phenomenon was relatively high volatility of light PAHs.

Analisis Pengaruh Variasi Jumlah Lapisan Biji pada Akurasi Prediksi Kandungan Minor Biji Kopi Arabika Hijau Bondowoso dengan NIR Spectroscopy

Void space in the bean layers will lead to the occurrence of non-fully interacted radiation (NFIR) affecting the reproducibility of NIRS measurements. Void space in addition to being affected by particle size is also influenced by the number/thickness of the bean layers. The objective of this study was to analyze the effect of number of bean layer variation on prediction accuracy of caffeine, chlorogenic acid and trigonelline in Bondowoso green Arabica coffee beans by NIR Spectroscopy (NIRS). The study was conducted using three kind of layers, i.e. 3, 4, and 5 layers, with 100 samples each. Samples were measured by FT-NIR spectrometer in wavelength of 1.000-2.500 nm. The pretreatment method used were second derivative (dg2), the combination of first derivative (dg1) and Multiplicative Scatter Correction (MSC), and the combination of dg2 and MSC, while calibration method used was Partial Least Square (PLS). The results shows that the accuracy of 5 layers was better than 3 or 4 layers. The best calibration and validation for caffeine was obtained by dg2 pretreatment and 6 factors of PLS (r = 0.99; SEC = 0.01%; SEP = 0.01%; and RPD = 5.40), for chlorogenic acid was by dg2 pretreatment and 5 factors of PLS (r = 0.99; SEC = 0.09%; SEP = 0.09%; and RPD = 4.76), whereas for trigonelline was by combination of (dg2, MSC) and 5 factors of PLS (r = 0.99; SEC = 0.01%; SEP = 0.01%; and RPD = 4.86). Therefore, the 5 layers can be used as a reference in NIRS measurement of coffee beans.

“CIRAGI”- The microbial fermentation starter for developing excellent coffee flavour

Most of the green bean coffees produced by smallholders are not properly fermented, while green bean coffees from large plantations undergo a spontaneous fermentation involving present microbial activity in the processing environment. The process of coffee fermentation itself involves not less than 144 endogenous microbial species originating from coffee fruits or from the surrounding environment. This condition is the source of inconsistency and low cup quality of coffee beans. The inoculation of selected microbial fermentation starter can transform microbial ecosystem. The transformation leads to beneficial microbes dominating and actively inducing flavour precursors into excellent aroma during roasting. The Indonesian Research Institute for Biotechnology and Bioindustry (IRIBB) has developed the CIRAGI (abbreviation of CItaRAsa tingGI meaning “a high flavour” in Indonesian), a fermentation starter for coffee beans using selected Lactobacillus sp. as the active ingredient. High cup quality coffee can consistently result from well-controlled fermentation process of the coffee bean using CIRAGI. The fermentation of both Robusta and Arabica coffee beans using CIRAGI has been demonstrated at laboratory and field trials. The cup tests of both Arabica and Robusta coffee have resulted in improved quality of the coffee flavour, increase of cup test scores based on the SCAA parameter, and elimination of off-flavour.

Identification of new diterpene esters from green Arabica coffee beans, and their platelet aggregation accelerating activities

Eight new ent-kaurane diterpene fatty acid esters, namely caffarolides A–H (1–8), were isolated from green beans of Coffea arabica. Their chemical structures were confirmed by extensive spectroscopic analysis including 1D, 2D NMR (HSQC, HMBC, 1H–1H COSY, and ROESY), HRMS, IR and CD spectra and by GC-FID analysis. Interestingly, the diterpene moiety of these new compounds first occurred in genus Coffea. All the isolates were evaluated for platelet aggregation activity in vitro. As the results, caffarolides C, D and F (3, 4 and 6) showed induction effect for platelet aggregation and the possible structure-activity relationships have been discussed briefly.

Neutron activation analysis of major and trace elements in Arabica and Robusta coffee beans samples consumed in Algeria

Abstract The Algerian neutron activation analysis laboratory is highly involved in nutrition applications in the framework of research activities using the Es-Salam research reactor. The main objective of this work is to contribute, by using nuclear analytical techniques, for studying a large number of natural food samples consumed in Algeria related to nutrition and human health. The present study focuses on the analysis of the most popular beans consumed worldwide, namely, the coffee species of Arabica and Robusta, based on the international markets. Chemical content of samples was assessed by instrumental neutron activation analysis (INAA) and k 0-INAA techniques, through the irradiation of samples during 6 h at a thermal neutron flux of 4.5×1013cm−2s−1 of Es-Salam research reactor. A total of 17 elements were assessed such as, (Br, Ca, Ce, Co, Cr, Cs, Fe, K, La, Na, Rb, Sc, Sm, Sr, Zn, Lu and Th) obtained by using INAA and k 0-INAA methods, While we used the radiochemical neutron activation analysis (RNAA and k 0-RNAA) to determine Selenium at low level concentrations, the accuracy of the method was evaluated by analyzing CRM and SRM. QC/QA was evaluated by using the statistical parameter U-score. Results were compared with those obtained for samples from Brazilian, Caribbean, Indian and Kenyan coffee beans reported in the literature. The daily intake of essentials and toxic elements was determined and compared with the recommended values. The probable cumulative intake of toxic elements was found to be well below the tolerance limits.

Mechanical behaviour of Arabica coffee (Coffea arabica) beans under loading compression

The uniformity of the product of the grinding process depends on various factors including the brittleness of the roasted coffee bean and it affects the extraction of soluble solids to obtain the coffee brew. Therefore, the reaching of a certain degree of brittleness is very important for the grinding to which coffee beans have to be subjected to before brewing. The aims of this study to show the mechanical behaviour of Arabica coffee beans from Tobasa (Indonesia) with roasted using different roasting time (40, 60 and 80 minutes at temperature 174 °C) under loading compression 225 kN. Universal compression testing machine was used with pressing vessel diameter 60 mm and compression speed 10 mm min-1 with different initial pressing height ranging from 20 to 60 mm. The results showed that significant correlation between roasting time and the brittleness.

Developing predictive models for determining physical properties of coffee beans during the roasting process

This study aims to evaluate and model the variation in the physical properties of coffee beans in isothermal roasting conditions, providing mathematical expressions that can be used for heat and mass transfer models for coffee roasting. Arabica coffee beans were studied with an initial moisture content of 0.129 kgw kgdm−1 and roasted in a direct gas burning roaster. Five temperatures were set inside the cylinder (200, 220, 240, 260 and 280 °C). The beans were roasted uniformly by suspension in the center of the drum. A thermocouple recorded the temperature every 5 s. X-ray microtomography was used to analyze the evolution of the internal matrix during the roasting process. The moisture content and physical properties (volume, surface area, and density) of each coffee bean were evaluated every 20 s. Empirical models were fitted to represent the physical properties as a function of the moisture content. It was observed that the volumetric expansion is isotropic at roasting temperatures above 220 °C. The final bean volume can reach up to 1.8 times the initial volume. The bean density varied linearly with the moisture content, presenting a larger drop at a higher roasting temperature.

Effect of altitude on biochemical composition and quality of green arabica coffee beans can be affected by shade and postharvest processing method

Although various studies have assessed altitude, shade and postharvest processing effects on biochemical content and quality of coffee beans, data on their interactions are scarce. The individual and interactive effects of these factors on the caffeine, chlorogenic acids (CGA) and sucrose contents as well as physical and sensory qualities of green coffee beans from large plantations in southwestern Ethiopia were evaluated. Caffeine and CGA contents decreased with increasing altitude; they respectively declined 0.12 and 1.23gkg−1 100m−1. Sucrose content increased with altitude; however, the altitude effect was significant for wet-processed beans (3.02gkg−1 100m−1), but not for dry-processed beans (0.36g kg−1 100m−1). Similarly, sucrose content increased with altitude with much stronger effect for coffee grown without shade (2.11gkg−1 100m−1) compared to coffee grown under shade (0.93gkg−1 100m−1). Acidity increased with altitude when coffee was grown under shade (0.22 points 100m−1), but no significant altitude effect was observed on coffee grown without shade. Beans grown without shade showed a higher physical quality score for dry (37.2) than for wet processing (29.1). These results generally underline the complex interaction effects between altitude and shade or postharvest processing on biochemical composition and quality of green arabica coffee beans.

Quantification of Free 2-Furfurylthiol in Coffee Brew Using a Prefabricated Coffee Model

A reliable and sensitive method was developed to quantify the free 2-furfurylthiol (2-FFT) in coffee brew. Using cysteine addition combined with vacuum distillation, a coffee model with trace 2-FFT and similar physicochemical properties as coffee brew was prepared for standard curve construction. During the model preparation, 2-FFT in bound form was released to free 2-FFT and removed from coffee brew through vacuum distillation. The method sensitivity, precision, accuracy and selectivity were evaluated. The limit of quantification (LOQ) was 3.0 μg/L. The coefficient of variation (CV) was 7.1%. The average recovery rates were 86.8–106.2% at spiked concentrations of 22.6, 135.8 and 181 μg/L. Coffee brews prepared using Robusta and Arabica roasted coffee beans were analyzed, and results showed that coffee brew from Robusta coffee beans had a greater amount of free 2-FFT (20.94 μg/L) than Arabica coffee beans from Yunnan (11.34 μg/L) and Columbia (15.33 μg/L), respectively. This method would be beneficial to investigate the free amount of 2-FFT in coffee brew and the sensorial assay based on free 2-FFT concentration.

Long-read sequencing of the coffee bean transcriptome reveals the diversity of full-length transcripts.

Polyploidization contributes to the complexity of gene expression, resulting in numerous related but different transcripts. This study explored the transcriptome diversity and complexity of the tetraploid Arabica coffee (Coffea arabica) bean. Long-read sequencing (LRS) by Pacbio Isoform sequencing (Iso-seq) was used to obtain full-length transcripts without the difficulty and uncertainty of assembly required for reads from short-read technologies. The tetraploid transcriptome was annotated and compared with data from the sub-genome progenitors. Caffeine and sucrose genes were targeted for case analysis. An isoform-level tetraploid coffee bean reference transcriptome with 95 995 distinct transcripts (average 3236 bp) was obtained. A total of 88 715 sequences (92.42%) were annotated with BLASTx against NCBI non-redundant plant proteins, including 34 719 high-quality annotations. Further BLASTn analysis against NCBI non-redundant nucleotide sequences, Coffea canephora coding sequences with UTR, C. arabica ESTs, and Rfam resulted in 1213 sequences without hits, were potential novel genes in coffee. Longer UTRs were captured, especially in the 5΄UTRs, facilitating the identification of upstream open reading frames. The LRS also revealed more and longer transcript variants in key caffeine and sucrose metabolism genes from this polyploid genome. Long sequences (>10 kilo base) were poorly annotated. LRS technology shows the limitation of previous studies. It provides an important tool to produce a reference transcriptome including more of the diversity of full-length transcripts to help understand the biology and support the genetic improvement of polyploid species such as coffee.

Analysis of underivatised low volatility compounds by comprehensive two-dimensional gas chromatography with a short primary column

Comprehensive two-dimensional gas chromatography (GC×GC) approaches with cryogenic modulation were developed for the qualitative analysis of selected low volatility compounds in raw coffee bean extracts, without derivatisation. The approaches employed short first (1D) and second (2D) dimension columns, specifically a 1D 65% phenyl methyl siloxane column (11m) and a 2D 5% phenyl methyl siloxane column (1m), which allowed elution of high molar mass compounds (e.g.>600Da). Solutes included hydrocarbons, fatty acids, diterpenes, tocopherols, sterols, diterpene esters, and di- and triacylglycerides. An oven temperature program up to 370°C was employed. The effects of experimental conditions were investigated, revealing that the GC×GC results strongly depended on the cryogenic trap T, and oven T program. An appropriate condition was selected and further applied for group type analysis of low volatility compounds in green Arabica coffee beans. Retention indices were compiled for 1D GC analysis and were similar for the composite column data in GC×GC. The elution of some compounds was confirmed by use of authentic standards. The approach allowed direct analysis of coffee extract in ethyl acetate solution, with improved analyte peak capacity (approximately 200 compounds were detected) without prior fractionation or pre-treatment of the sample. This avoided potential hydrolysis of high molar mass conjugate esters as well as degradation of thermally labile compounds such as the derivatives of the diterpenes cafestol and kahweol.