Coffee Science (E-Journal)
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Caffeine content in Nepalese coffee: Influence of brewing methods and storage time
Full text linkCoffee’s global appeal, attributed to its caffeine content impacting flavor and health, lacks thorough exploration of Nepalese coffee despite its growing coffee sector. The lack of comprehensive studies inhibits informed choices on caffeine consumption and coffee selection. Here, we aimed to bridge this gap by assessing caffeine content and pH levels in Nepalese coffee beans using common extraction methods - boiling, French Press, and Moka pot. We compared ten locally sourced coffee brands from Pokhara, Nepal, conducting the experiment upon unsealing the coffee packets, designated as day 0, and repeated it after 21 days with the same samples, labeled as day 21. An Ultra Performance Liquid Chromatography (UPLC) with a UV/Visible detector was used to estimate caffeine concentration. The Moka pot maintained the highest average caffeine concentration at 14.39±1.87 mg/g (day 0) and 13.83±1.24mg/g (day 21), followed by boiling at 11.63±1.17 mg/g (day 0) and 10.16±1.63 mg/g (day 21), with the French press yielding the lowest concentration at 10.11±0.96 mg/g (day 0) and 8.90±2.09 mg/g (day 21). pH values varied, with the boiling method resulting in the highest pH (5.51±0.22). Coffee pH increased from 5.41±0.20 to 5.45±0.21 over 21 days. Our findings underscore the importance of considering extraction methods when evaluating coffee’s caffeine content and pH levels. This study provides valuable insights for consumers to make informed choices about caffeine intake and coffee preferences. Further research could explore additional factors influencing caffeine content and pH levels, such as regional differences, cultivation practices, titratable acidity, sensory evaluations, and chemical profiling.
Key words: UPLC analysis; pH; moka pot; french press; boiling
Carbon Nanotechnology-Based Sustainable Solutions for Mitigating Drought Stress in Coffee Plants
Full text linkCarbon nanoparticles (CNPs) have emerged as promising nanomaterials in agriculture because of their unique physicochemical properties. The present study investigates the impact of CNPs on the growth and physiology of a local coffee variety (Coffea arabica cv. Shadawi Salibi) in Saudi Arabia under drought conditions. Although several studies have examined the effects of drought on this coffee variety, fewer have focused on the impact of carbon nanoparticles, particularly concerning important factors like gas exchange and proline accumulation in coffee plants under drought conditions. Therefore, various doses of carbon nanoparticles Bulk C (0, 5, 15), CNPs(M) (0, 5, 15), and CNPs(F) (0, 5, 15) were tested to determine their potential effects on the growth and development of coffee plants. Treatment with CNPs including Bulk C, CNPs(M), and CNPs(F) at 5 mM and 15 mM significantly improved root and shoot length, as well as fresh and dry biomass, in coffee plants subjected to drought stress. Typically, drought stress severely reduces photosyntheticpigments (Chl a, Chl b, carotenoids), relative water content, gas exchange (net photosynthesis, stomatal conductance), chlorophyll fluorescence (Fv/Fm), and antioxidant activities. However, CNPs application notably alleviated these negative effects. Additionally, CNPs treatments reduced malondialdehyde (MDA) levels and proline accumulation, indicators of oxidative and osmotic stress, respectively. These findings suggest that treating coffee plants with CNPs enhances their tolerance to drought stress.
Key words: Chlorophyll; ma londialdehyde; nanotechnology; photosynthesis; stomatal conductance
Resposta do cafeeiro conilon à adubação de npk em sistema de plantio adensado
Full text linkThe response of plants to the application of fertilizer varies in function of diverse factors, among them we highlight the type of soil, dose of nutrient, and spacing used. Thus, the objective of this work was to evaluate the effect of NPK application in the production of Conilon coffee plants (Coffea canephora Pierre ex Forehn.), cultivated in different densities of planting. The studied were composed of four quantities of N (0, 150, 300 and 450 kg ha-1), four of P2O5 (0, 50, 100 and 150 kg ha-1), four of K2O (0, 150, 300 and 450 kg ha-1) and four densities of planting: 2,0 x 1,0 (5000 plants ha-1); 2,5 x 1,0 (4000 plants ha-1); 3,0 x 1,0 (3000 plants ha-1) and 3,0 x 1,5 m (2222 plants ha-1). It was used the experimental design in randomized blocks, being the treatment distributed in four blocks arranged in a factorial fractional (4 x 4 x 4)1/2 scheme. There was a reduction in the dose of nitrogen in relation to those normally recommended for the Conilon coffee plants. The potassium did not influence the production. The phosphorus increased the productivity; however, it was not possible to determinate the maximum economic dose. There were no interactions between the densities of planting and the level of NPK applied. As respostas das plantas à aplicação de fertilizantes variam em função de vários fatores, dentre os quais se destacam o tipo de solo, doses dos nutrientes e o espaçamento utilizado. O objetivo deste trabalho foi avaliar o efeito da adubação de nitrogênio, fósforo e potássio (NPK) na produção do cafeeiro Conilon (Coffea canephora Pierre ex Froehn.), cultivado em diferentes densidades de plantio. Foram utilizadas quatro doses de N (0, 150, 300 e 450 kg ha-1), quatro de P2O5 (0, 50, 100 e 150 kg ha-1), quatro de K2O (0, 150, 300 e 450 kg ha-1) e quatro densidades de plantio: 2,0 x 1,0 (5.000 plantas ha-1); 2,5 x 1,0 (4.000 plantas ha-1); 3,0 x 1,0 (3.000 plantas ha-1) e 3,0 x 1,5 m (2.222 plantas ha-1). Foi utilizado o delineamento experimental em blocos casualizados, sendo os tratamentos distribuídos em quatro blocos arranjados em um esquema de fatorial fracionado (4 x 4 x 4)1/2. Houve uma redução na dose de N em relação às doses normalmente recomendadas para o cafeeiro Conilon. O K não influenciou a produtividade. O P aumentou a produtividade, entretanto, não foi possível determinar a dose máxima econômica. Não houve interações entre as densidades de plantio e os níveis de NPK avaliados.
Assessment of alcoholic native yeasts isolated from the fermentation of wet processed coffee (Coffea arabica)
Full text linkBiofuels produced from waste biomass are the best alternative to fossil fuels; however, considering that bioethanol production occurs due to fermentation, the yield should be improved during this stage by incorporating microorganisms that can increase yields in the conversion of carbohydrates present in the residue to ethanol. Therefore, native yeasts were isolated and identified from natural fermentation of coffee cherries (Coffea arabica) from Chiapas, Mexico, and then, evaluated the yield of ethanol. First, a morphological study was conducted in which yeast-like microorganisms were isolated from plates with a YPDA culture medium, taking into account their texture, surface, margin, elevation, and color. In total, 15 isolates with macroscopic and microscopic characteristics typical of yeasts were obtained. Subsequently, biochemical tests were conducted to evaluate the fermentative capacity of the strains; simple sugars such as glucose, fructose, sucrose, lactose, and xylose were tested in a liquid medium composed of 0.3% yeast extract, 0.5% peptone, and 2% simple sugar. The mixture was incubated for 48 h at room temperature. The strains fermented with the aforementioned sugars were subjected to a qualitative iodoform test to confirm the presence of ethanol in the medium, identifying the best M2A and M2B strains with yields of 3.7 and 18 g/L, respectively. The M2A strain corresponded to Wikerhamomyces anomalus, and the M2B strain corresponded to Pichia kudriavzevii. To summarize, native yeasts represent a biological alternative to the production of bioethanol, which guarantees the conversion of the sugars present in the substrate to ethanol.
Key words: Bioethanol; fermentation of coffee cherry; native yeasts; non-Saccharomyces; residue
Effect of temperature and photoperiod on Pseudomonas syringae pv. garcae inoculum production
Full text linkBacterial halo blight (BHB), whose etiological agent is the bacterium Pseudomonas syringae pv. garcae, is one of the main diseases occurring in coffee (Coffea arabica L.) leading to losses in nurseries and fields. This study aimed to assess the effect of five temperatures (20, 25, 30, 35, and 40 °C) and three photoperiods (continuous light, 12-hour light/dark, continuous dark) on the P. syringae pv. garcae inoculum concentration and the BHB progression re sulted from this inoculum, in coffee seedlings. Using a factorial design (5 x 3) with four replicates, Petri dishes inoculated with P. syringae pv. garcae were incubated for 48 hours, and the concentrations and bacterial cell dimensions were measured. The resulting inoculum was then used to inoculate coffee seedlings at 23 ± 2 °C in one leaf pair by wounding inoculation using a multi-needle apparatus. The disease severity was assessed, and the area under the disease progress curve (AUDPC) was calculated. Significant interaction (p < 0.05) between temperature and photoperiod was observed for inoculum concentration and cell dimensions. The highest inoculum concentration (2.2 x 10⁹ CFU/ml) was recorded at 25 °C under continuous light. The largest bacterial cells (4.4 µm in length and 0.7 µm in width) resulted from temperatures of 30 °C with 12-hour light/dark. For the AUDPC of BHB, a difference (p < 0.05) was observed only between inoculum production temperatures. The highest AUDPC was recorded at 25 °C, with a gradual decline observed as the temperature increased.
Key words: Bacterial inoculation; bacterial halo blight; Coffea arabica L.; concentration; disease severit
New orthotropic stems induction in arabica coffee by pruning and biostimulant application
Full text linkPruning are techniques used to renew a coffee tree and promote the growth of a more vigorous plant. Allied to that, the use of biostimulants can help the boost growth and development of the new produced stems. The objective of the present work was to evaluate whether the presence of plagiotropic branches in coffee trees pruned by low pruning and the application of biostimulant would influence the production, growth and vigor of new orthotopic branches in Coffea arabica. The experiment consisted of 10 treatments, arranged in a randomized block design with a 2x5 factorial: two pruning methods (low pruning with and without plagiotropic branches) and five doses of Stimulate® (0, 100, 200, 400 and 800 mL). The traits evaluated were vigor of the orthotropic branches produced vigor, orthotropic branches length, number of orthotropic branches orthotropic and orthotropic branches diameter. The use of low pruning with remaining plagiotropic stems combined with the use of biostimulants at a dose of 400 mL induces the production of vigorous orthotropic stems in Arabica coffee trees.
Key words: Coffea arabica; coffee pruning; phytohormones; shoots
Enzymes activity as potential molecular markers for drying tolerance and quality in Coffea arabica seeds
Full text linkAntioxidant enzyme expression plays a vital role in the stress response in plants. This study evaluated the physiological quality and antioxidant enzyme expression of coffee seeds and plants subjected to drying. Coffee seeds were conventionally dried to 40% and 10% water content, representing nonstressed and stressed conditions, respectively. The tests included germination, accelerated aging, and emergence. The expression of enzymes (SOD, CAT, POX, APX, and 1-cys-prx), together with lipid peroxidation, was analysed. The results showed no significant differences in the physiological test results, except for germination in stressed seeds. We found differences in antioxidant system enzymes according to the condition applied to the seeds; however, only for peroxidase, lipid peroxidation, and 1-cys-prx were the observed patterns more strongly correlated with seed germination. Nevertheless, only lipid peroxidation and 1-cys-prx were more strongly correlated with germination, indicating its potential as a marker for coffee seed quality.
Key words: Coffee; drought; oxidative stress; 1-cys-prx
Free radical scavenging activity-based antioxidant analysis and infrared spectroscopy of peppermint-flavored coffee drink
Full text linkPeppermint essential oil canserve as a healthy flavoring additive to coffee drinks and provide health benefits by enhancing their antioxidant activity. Hence, this study aimed to examine the antioxidant activity of peppermint-flavored coffee drinks using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2’-azinobis-(3-ethylenebenzothiazoline)-6-sulfonic acid (ABTS) free radical scavenging assays. Furthermore, Fourier transform infrared-attenuated total reflectance spectroscopy was performed to investigate the profile of compounds contributing to the antioxidant property. The experiments were conducted using a Complete Randomized Block Design with six replications. Two-factor treatments were as follows: soaking time (S), 0 (S0), 5 (S1), and 10 (S2) min; peppermint essential oil concentration (E), 0 (E0), 0.5 (E1), and 0.75% (E2) (v/v). N otably, both DPPH and ABTS assays revealed increased antioxidant activity of peppermint-flavored coffee drink where the coffee was soaked for 10 min in 0.75% peppermint solution. The coffee soaked for 10 min in 0.5% and 0.75% peppermint solutions showed a high scavenging effect against ABTS free radical, with 93.73 and 94.30% inhibition activity and half-maximal inhibitory concentrations of 0.272 and 0.267 ppm, respectively. Additionally, a new peak was observed at 1640 cm−1in peppermint solution-soaked coffee beans,which corresponded tothe C=C functional group in the limonene spectrum, an antioxidant compound in peppermint. Altogether, the findings show that peppermint essential oil enhanced the antioxidant activity of the coffee.
Key words: ABTS; antioxidant; DPPH;FTIR-ATR; peppermint-flavored coffee
Development a novel and comprehensive cupping protocols for wine coffee assessment using Qualitative Description Analysis
Full text linkDiversification of coffee product and cnsumer demands attempt to create a new product such as wine coffee, a fermented coffee product which undergo the coffee cherries fermentation process up to 30 days or longer. As a new product, coffee wine does not have quality standard, which barriers the coffee trade and trust between coffee producers and buyer. This research aims to develop a novel and comprehensive cupping protocol for wine coffee using Qualitative Description Analysis with the presence of Specialty Coffee Association of America as guidelines. QDA is parted to three section panellist screening, panellist training and product evaluation. From 20 screened panellists, 12 are undergo to training panellist, but only 8 panelists shows consistent results, share similar understanding about wine coffee quality. The results showed that fragrance, aroma, flavour, body, aftertaste and acidity have different definition than specialty coffee from SCAA cupping protocols.
Key words: Arabica; aftertaste; cherries; fermented; wine coffe
Physicochemical and sensory profile of commercial wine coffee in the Gayo Highlands, Indonesia
Full text linkThe Gayo Highlands is one of the largest Arabica coffee producing areas in Indonesia. Wine coffee processing is currently very popular in the Gayo Highlands. This study aims to determine of physicochemical and sensory characteristics of commercial wine coffee in Gayo Highlands. Samples were obtained from active wine coffee producers in Central Aceh and Bener Meriah. Analysis was carried out on coffee beans and brewing, including analysis of bean size, moisture content, color, pH, total dissolved solids (TDS), total phenolic content (TPC), and cupping quality. The results found that Gayo arabica wine coffee has a medium size, moisture content of 8.53%-11.67%, and yellow to brown color. Physicochemical characteristics of brewed wine coffee also showed varying results. The pH of coffee wine brewing ranges from 4.68 to 4.95, TDS 3.93 to 4.5 oBrix, and TPC 12.82 to 30 GAE mg/g. Sensory analysis was conducted using the cupping test method. The cupping score of wine coffee on each attribute varied, except body and sweetness. The wine coffee aroma obtained was 6 (good) to 7.75 (very good), wine coffee flavor 6 (good) to 7.5 (very good), wine coffee aftertaste 6 (good) to 7.0 (very good), wine coffee acidity 6 (good) to 7.0 (very good), wine coffee balance 6 (good) to 6.75 (good), overall wine coffee 6 (good) to 7 (very good). Specific fruit aroma characteristics that dominated the coffee wine were pineapple, banana, passion fruit, lemon/lime, and berries. Aroma characteristics related to fermentation, namely winey, vinegar, overripe, and soury were detected in all wine coffee samples. Further research is needed to analyze the more complex chemicalcomponents of wine coffee (volatile and non-volatile) and their correlation with brewing quality to obtain more comprehensive scientific information on wine coffee quality.
Key words: Gayo wine coffee; Chemical characteristic; Cupping test; Sensory profile