Coffee Science (E-Journal)
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The Performance of cross laminated timber panels made of Pinus oocarpa and Coffea arabica waste
No full textThe growth of the civil construction sector, made necessary to develop alternative products made of sustainable materials. Within this context came the cross laminated timber panels (CLT), which are formed by gluing veneer arranged at 90°, which provide high strength and great versatility, as constructive elements. This research aimed to evaluate the chemical properties of the particles of both materials and evaluate the performance of CLT panels made with Pinus oocarpa and waste wood from Coffea arabica. The panels were made with three orthogonal layers with veneer of pine and coffee wood, using the phenol-formaldehyde (PF) adhesive with a spread rate of 0.35kgm-² and the hydraulic press with a pressure of 1,2×107 N.m-2for 15 min. The physical, mechanical properties, acoustic and thermal performance of the panels were evaluated. There was a significant difference for water absorption in 2 and 24 hours. The panels produced only with coffee wood waste showed the lowest water absorption rates, corresponding to 10.2 and 33.3%, in 2 and 24 hours. In relation to the MOE, the panels made with varied veneer were statistically equivalent to each other and the panels made of pine blades showed a MOE corresponding to 3,33×107 N.m-2. The same trend was observed for MOR, since the average value obtained for pine panels, corresponding to 1,35x108 N.m-2 was significantly higher. Panels made of coffee veneer and pine veneer showed no delamination. With regard to acoustic and thermal evaluation, all panels met the minimum requirements indicated in the standards, with emphasis on coffee wood waste, associated or not with pine wood.Key words: Adhesive; Coffee; Chemical analysis; Hybrid panel; Technological properties
Sensory analysis and mid-infrared spectroscopy for discriminating roasted specialty coffees
Get PDFIn general, the process of roasting coffee uses a rotated fix drum or fluidized bed. Theoretically, the fluidized bed can provide more homogenous roastings throughout the process. Thus, in this study, we analyzed the sensorial and chemical attributes for two different coffees submitted to three roasting profiles using fluidized bed roaster. The coffees were roasted for a high temperature for a short time (HTST), medium temperature for a medium time (MTMT), and low temperature for a long time (LTLT). Sensory analysis was performed on the roasted coffees according to the SCA methodology and chemical analysis through mid-infrared spectroscopy. The results of sensory analysis indicated a preference for MTMT roasting for coffee grown at high altitude and HTST roasting for coffee grown at low altitude. Chemically, coffees show that LTLT and MTMT roasts are most distant from each other in their chemical composition when roasting low altitude coffee, whereas the HTST and MTMT roasts are the most distant from each other when roasting high altitude coffee.
Key words: Arabica coffee; Coffee roasting; Infrared spectroscopy; Specialty coffee
Origin of black-green defect in the artificial drying of immature coffees
Get PDFThe unevenness of coffee maturation leads to a large portion of green berries in the harvest. Post-harvest management techniques seek to minimize defects during the drying process, such as black-green defects in harvested immature berries. The present study aimed to investigate the minimum occurrence of black-green defects in the drying of immature coffee berries subjected to different temperature conditions and relative humidity values. In addition to fitting mathematical models to the experimental data, the effective diffusion coefficient and the water reduction rate (WRR) were determined. Nine coffee crops (Coffea arabica L.) of the Topázio Amarelo variety were harvested manually and selectively during the green maturation stage, with an initial water content of 2.106 ± 0.05 kg.kg-1 (dry basis, d.b.). After drying, the coffee was subjected to a drying treatment in a fixed-layer dryer with combined dry bulb temperatures (Dbt) of 35, 40 and 45 °C and dew point temperatures (Dpt) of 2.6, 10.8 and 16.2 °C until a final water content of 0.124 ± 0.05 kg.kg-1 (db) was reached. After drying, black-green defects were quantified as percentages. In addition to the drying kinetics, the WRR and effective diffusivity were evaluated. The lowest percentage of black-green defects occurred at a temperature of 35 °C and a Dpt of 2.6 °C (11.00%), which is the most suitable treatment for drying natural green coffees. The highest percentage of defects occurred when a Dbt of 35 °C was combined with a Dpt of 16.2 °C (14.17%). This combination showed the lowest effective diffusion coefficient of 0.551 x 10-11 m2 s-1. The Midilli model had the best fit to the experimental data for all drying combinations. The lowest WRR was 0.063 kg.kg-1.h-1 and was observed when a Dbt of 35 °C was combined with a Dpt of 16.2 °C.
Keywords: Drying; Coffee; Diffusion coefficient; Mathematical modelling
Evaluation of physical parameters of green and roasted arabica coffee using the scilab® free software
Get PDFThe physical and chemical parameters of coffee beans make it possible to assess begerage quality before and after the roasting process. Currently, the use of software as a tool provides the verification and compilation of graphics, resulting in a better visualization of techniques and data separation. The physical parameters of soft, hard and rio coffees were evaluated regarding type, sieve and color, and the chemical composition was represented by moisture content, ether extract, protein, ash, soluble solids and total titratable acidity. Different roasting levels were assessed for the beverages and the parameters color and mass loss were verified. The results were analyzed with the aid of the Sisvar software and graphics were plotted using the Scilab® free software. Rio coffees showed lower physical classifications in relation to type and showed a lighter color; for sieving, all showed a higher percentage of flat coarse beans. The moisture content showed values according to the current legislation; ether extract, protein content and ash were as expected. The rio beverage had lower levels of soluble solids and higher total titratable acidity. After the roasting process, the parameters L*, b*, C* and H* showed a decrease, since the mass loss increased with the roasting level, but there was no difference between beverages. The samples were well located within the roasting scopes and L* was the parameter that best differentiated the samples, thus constituting an important factor for determining the roasting point.
Key terms: Coffea arabica L.; Quality; Roasting; Color
Nutritional efficiency in phosphorus of arabica coffee genotypes
Get PDFNutritional efficiency is a term used to characterize plants in their capacity to uptake and use nutrients, being related to the efficiency of uptake, translocation and utilization of nutrients. Different coffee genotypes are expected to exhibit variability in their nutritional efficiency. This work aimed to evaluate the phosphorus nutritional efficiency in arabica coffee genotypes. The experiment was conducted in a greenhouse of the Empresa de Pesquisa Agropecuária de Minas Gerais (EPAMIG), located in the municipality of Lavras – Minas Gerais, Brazil. The experimental design was a randomized complete block design, in a 10x2 factorial scheme (10 arabica coffee genotypes and two dosages of phosphate fertilization), with four replications. Each experimental plot consisted of one pot with ten liters of soil, with one plant. The cultivars Catiguá MG2, MGS Ametista and Sarchimor MG 8840 are neither efficient nor responsive to phosphate fertilization. Progeny H 6-47-10 pl. 3 and the cultivar Catuaí Vermelho IAC 144 are not efficient but are responsive to phosphate fertilization. The cultivars Paraíso MG H 419-1, Topázio MG 1190 and MGS Paraíso 2 are efficient but are not responsive to phosphate fertilization. The cultivars Bourbon Amarelo IAC J10 and MGS Aranãs are efficient and responsive to phosphate fertilization.
Index terms: Coffea arabica; Cultivars; Mineral nutrition
Young coffee leaves biotransformed by aspergillus oryzae in enriched source of caffeic acid
Get PDFThis research focused on the study of young coffee leaves as a potential source of caffeic acid from the biotransformation of abundant chlorogenic acid. Aspergillus oryzae was isolated from koji rice and used for the solid-state fermentation of coffee leaves. The bioconversion of chlorogenic acid into caffeic acid was measured by HPLC-DAD. The water infusions of fermented coffee leaves were analyzed by sensory evaluation in comparison with unfermented coffee leaves as well as roasted coffee beans. The biotransformation of young coffee leaves yielded over 3.5-fold change increase of caffeic acid natural content in 87 hours, and equivalently, decreasing concentrations were observed for chlorogenic acids. Other bioactive compounds, such as mangiferin, rutin and caffeine, showed relatively minor changes. Sensory evaluation pointed out the effect of increasing caffeic acid-concentration on bitterness and astringency, which would have to be considered in the development and optimization of functional foods. As bitterness was increased by the enhanced caffeic acid concentrations, desirable flavor descriptors were also associated with fermented leaves, with the inclusion of notes traditionally associated with koji. This bioprocess proved to be highly efficient and could be implemented with relatively simple technology in-farm production systems.
Key words: Coffee leaves; Coffee biomass; Caffeic acid; Aspergillus oryzae
Effect of tropical millipede Rhinocricus botocudus in the degradation and maturity of coffee residues
Get PDFIn Brazil, approximately 3 tons of dry mass per hectare of coffee residues (CR), formed by leaves and branches <5 mm in diameter, were accumulated around the crops in the last harvests of the semi-mechanized crops. Thus, the production of substrates and organic fertilizers from the bioconversion of residues of coffee activity is an important theme in Brazil and in the world. The objective of the study was to investigate the effectiveness of the tropical millipede Rhinocricus botocudus on the degradation and maturity of coffee residues (CR). The presence and absence of R. botocudus were tested in five sampling times (0, 30, 60, 90, and 120 days) with three replicates (n = 3). The analyzed variables were: total C and N contents, lignin, cellulose, soluble C and N, soluble polyphenols, C of humic substances, and infrared analysis of humic acid (HA) and fulvic acid (FA). At the final incubation stage (120 days), the lowest values of cellulose, cellulose/lignin, and polyphenols occurred with R. botocudus. Infrared analysis of HA demonstrated that readily biodegradable structures, such as alcohols and short chain aliphatic molecules, were decomposed over time, consequently reflecting the increase of aromatic structures of greater stability. Compared to the control, these changes in HA were more evident in the presence of R. botocudus. The results of the present study suggest that this millipede species alters the dynamics of degradation and humification of CR by accelerating the maturity of this residue.
Key words: Cellulose; humic substances; lignin
Interaction between climate, flowering and production of dry coffee (Coffea arabica L.) in Minas Gerais
Get PDFAiming to determine the interaction between climatic factors, flowering and yield of dry arabica coffee in municipalities in the regions of Southern Minas Gerais and Alto Paranaíba, both in the State of Minas Gerais, this study considered data from the harvest years 2008/2009 to 2017/2018, and climatic data analyzed according to the coffee phenological cycle. The determination of significant variables used the Stepwise method and the Akaike Information Criterion (AIC). The association of yield with climatic variables used a generalized linear model with gamma distribution and logarithmic function. Average flowering (20% to 50% of flowers per branch) used a logistic regression model. The productive variability of arabica coffee showed an association with the biennial cycle, the occurrence of medium and main flowering, flowering period and rains in bean formation. The occurrence of average flowering andthe frequency of rainfall during bean formation enhanced coffee yield, at the same time as the increment in maximum temperature in vegetative bud formation reduced flowering and yield.
Key words: Phenological cycle of coffee; Temperature; Yield
Evaluation of species transfer models in the cfd simulation of fixed bed soybean drying
Get PDFThe drying is fundamental to the preservation of materials, particularly food, which is sensible to damaging related to moisture because of its hygroscopic nature. The drying increases the shelf life of these products and reduces their overall weight, which facilitates the logistics and aggregates value to the product. Computational Fluid Dynamics is a potentially facilitating tool for the analysis of drying variables, such as velocity, air temperature, and particle temperature, which have great influence on the drying rate. This work aimed at studying different numeric models for the simulation of a fixed bed drying operation, analyzing the influence of the equilibrium ratio and water diffusivity in the solid on the results. The computations were made in the software FLUENT 19.2, using the Multiphase Eulerian Granular Model with packed bed configuration and different mass transfer models: Constant, Species-Constant, Species-Sherwood, Ranz-Marshall, and Hughmark, as well as heat transfer models: Constant Heat Transfer Coefficient, Constant Nusselt Number, Ranz-Marshall, and Hughmark. The mass transfer models with the best performance were the Ranz-Marshall and Hughmark models. A strong influence of the equilibrium ratio was observed for both models, and a moderate influence of the water diffusivity. The influence of equilibrium ratio and water diffusivity was not observed for the other models. The heat transfer models did not present expressive difference, and the system reached thermal equilibrium quickly. The overall study of the models and the influence of different parameters was effective, and was able to document the obtained results for future optimization and further investigation of the numeric model.
Key words: Computational fluid dynamics; Diffusivity; Particle; Eulerian; Mass transfer
Nutritional composition and caffeine content of coffee-galangal affected by the variation of sweetener addition
Get PDFCoffee-galangal is a herb coffee, a mixture of coffee powder and galangal powder, which has a different aroma and taste and the galangal itself has excellent properties for the body. The sweetener commonly used in products is sucrose based sugar. The purpose of this study was to determine the effect of the use of sweetener on the chemical properties and caffeine content, such as cane sugar, palm sugar and alcoholic sugar. The nutritional composition were determined by carbohydrate content, protein content, fat content, water content, and caffeine content. The addition of sweetenersin the form of cane sugar, palm sugar, and alcoholic sugar is in coffee-galangal was significantly different from the unsweetened control treatments on the parameters of carbohydrate content, water content, ash content, and fat content, but did not significantly affect protein content. The use of different types of sweeteners added to coffee-galangal products significantly (α = 5%) on total carbohydrate, water, ash, and fat content. The parametervalues of the chemical properties of the product in this study were: carbohydrate content of 64.47-82.60%, water content 5.19-17.08%, ash content 1.74-4.47%, fat content 3.25 - 6.79%, protein content from 4.96 to 7.5%, and caffeine content 0.68 – 1.79 %. Finding in this study showed that alcoholic sugar has the highest percentage of caffeine content and the lowest carbohydrate content.
Key words: herb coffee, coffee-galangal, sweetener, chemical composition, caffei