Coffee Cherries Research Articles

An Agent-Based Model Driven Decision Support System for Reactive Aggregate Production Scheduling in the Green Coffee Supply Chain

The aim of this paper is to contribute to the thread of research regarding the need for logistic systems for planning and scheduling/rescheduling within the agro-industry. To this end, an agent-based model driven decision support system for the agri-food supply chain is presented. Inputs in this research are taken from a case example of a Mexican green coffee supply chain. In this context, the decision support agent serves the purposes of deriving useful knowledge to accomplish (i) the decision regarding the estimation of Cherry coffee yield obtained at the coffee plantation, and the Parchment coffee sample verification decision, using fuzzy logic involving an inference engine with IF-THEN type rules; (ii) the production plan establishment decision, using a decision-making rule approach based upon the coupling of IF-THEN fuzzy inference rules and equation-based representation by means of mixed integer programming with the aim to maximize customer service level; and (iii) the production plan update decision using mathematical equations once the customer service level falls below the expected level. Three scenarios of demand patterns were considered to conduct the experiments: increasing, unimodal and decreasing. We found that the input inventory and output inventory vary similar over time for the unimodal demand pattern, not the case for both the increasing and decreasing demand patterns. For the decreasing demand pattern, ten tardy orders for the initial production schedule, an 88% service level, and nineteen tardy orders from the estimated production results, a 77% service level. This value falls below the expected level. Consequently, the updated aggregate production schedule resulted in ten tardy orders and an 88% service level.

Influence of Various Processing Parameters on the Microbial Community Dynamics, Metabolomic Profiles, and Cup Quality During Wet Coffee Processing.

Post-harvest wet coffee processing is a commonly applied method to transform coffee cherries into green coffee beans through depulping or demucilaging, fermentation, washing, soaking, drying, and dehulling. Multiple processing parameters can be modified and thus influence the coffee quality (green coffee beans and cup quality). The present study aimed to explore the impacts of these parameters, including processing type (depulping or demucilaging), fermentation duration, and application of soaking, on the microbial community dynamics, metabolite compositions of processing waters (fermentation and soaking) and coffee beans, and resulting cup quality through a multiphasic approach. A large-scale wet coffee processing experiment was conducted with Coffea arabica var. Catimor in Yunnan (China) in duplicate. The fermentation steps presented a dynamic interaction between constant nutrient release (mainly from the cherry mucilage) into the surrounding water and active microbial activities led by lactic acid bacteria, especially Leuconostoc and Lactococcus. The microbial communities were affected by both the processing type and fermentation duration. At the same time, the endogenous coffee bean metabolism remained active at different stages along the processing, as could be seen through changes in the concentrations of carbohydrates, organic acids, and free amino acids. Among all the processing variants tested, the fermentation duration had the greatest impact on the green coffee bean compositions and the cup quality. A long fermentation duration resulted in a fruitier and more acidic cup. As an ecological alternative for the depulped processing, the demucilaged processing produced a beverage quality comparable to the depulped one. The application of soaking, however, tempered the positive fermentation effects and standardized the green coffee bean quality, regardless of the preceding processing practices applied. Lastly, the impact strength of each processing parameter would also depend on the coffee variety used and the local geographical conditions. All these findings provide a considerable margin of opportunities for future coffee research.

Sustainable management of coffee fruit waste biomass in ecological farming systems at West Lampung, Indonesia

Present study focuses on fruit waste biomass generated during the postharvest treatments of coffee cherries (Coffea spp.) and its subsequent utilization within the waste-less, sustainable and ecological farming systems. Investigated samples were collected at the organic shaded multi-culture coffee plantations in West Lampung, Indonesia. Within the determination of most suitable subsequent utilization, the samples were subjected to the analysis of their basic chemical parameters, energy potential and ash composition. Three samples kinds were defined: I. CP (outer skin, pulp), II. CH (husk, silver skin, parchment) and III. CA (burned mixture of previous two waste materials). Obtained values proved following results; CP: Mc - 79.21%, Ac - 2.05%, CV - 17.19 MJ/kg; CH: Mc - 21.08%, Ac - 6.50%, CV - 18.14 MJ/kg; CA: Mc - 30.79%, Ac - 28.11%. Measured values proves the suitability of tested materials for combustion processes as a renewable source of clean energy (high energy potential), but also for the composting purposes (Potassium content K2O - 10.946%). A great potential of tested materials within their subsequent reuse was proved, as well as the fact that they represent a commodity suitable for further valorization.

Cellulolytic and Xylanolytic Actinomycetes selection to degrade Lignocellulosic biomass of Robusta coffee pulp (Coffea canephora)

Actinomycetes are bacteria that have a high ability to produce hydrolytic enzymes that can be applied to degrade coffee pulp which contains lignocellulose components. Coffee pulp is residues from a coffee industry that can be used as substrates in the solid state fermentation process. In this study, cellulase and xylanase activity from actinomycetes isolates were investigated. Screening of these enzymes activity was using agar medium supplemented with 1% carboxymethylcellulose (CMC) and xylan from beechwood as substrate. Production of clear zones surrounding isolates on CMC and xylan agar medium was considered as indicative of extracellular cellulase and xylanase activity. The size of a transparent zone diameter was considered as proportional to the level of cellulase and xylanase production. Congo red 0,1% was used for staining. Selected actinomycetes isolates were continued to growth investigation on agar medium supplemented with 1% coffee pulp. The clear zone formed around isolates indicated that the isolate had the ability to degrade the lignocellulose component in the coffee pulp. The results show that of the 99 actinomycetes isolates tested on agar medium supplemented with 0.1% CMC and xylan, 16 isolates showed cellulase activity (cellulase index ≥ 2), 20 isolates showed xylanase activity (xylanase index ≥ 1), and 5 isolates showed both activities. Ten isolates have the ability to grow and produce a clear zone on the coffee pulp agar medium with cellulase and xylanase activity. Among these ten tested isolates; HJ4.5b, P2b(b).3, P2b(b).4, and P2b(b).18 are the most potential isolates that can be continued for further research on fermentation coffee cherries.

Prevalence of spoilage mold in coffee before and after brewing

Commercial ground coffee must be safe for consumption and comply with the regulation applied in a country. However, the risk of the occurrence of spoilage molds in commercial ground coffee, particularly toxigenic mold originated from coffee cherries or green beans, is still a major concern of the coffee industry. This study evaluated the prevalence of spoilage mold in fifteen brands of commercial ground coffee. The spoilage molds were also determined after traditional brewing (non-filtration brewing). The mold counts were enumerated on dichloran-glycerol 18% agar by spread plate method. The spoilage molds were also morphologically identified after isolation on malt extract agar and potato dextrose agar. The results showed that low numbers of molds were found in all samples before brewing, in a range of 10 to 200 CFU/g. A total of eleven genera were identified. Aspergillus, Cladosporium and Penicillium were found as the predominating genera. After brewing, molds from genera Alternaria and Aspergillus were still found. However, the total counts decreased to the level between undetected to an average of 3 CFU/mL. This study highlighted that very low levels of spoilage mold was recovered after brewing which may not pose a health risk.

Review on Post-harvest and Green Bean Coffee Processing in Ethiopia

Coffee (Coffea Arabica L.) is the major source of currency for Ethiopia and contributes more than 35% of the total export earnings. It is originated in Ethiopia. Coffee belongs to the family Rubiacea and the genus Coffea. The two main species of Coffee cultivated on a world scale are Arabica Coffee (Coffea arabica L.) and Robusta Coffee (Coffea canaphora L.), which account for about 98-99% of the world Coffee production. Even if the high production potential and economic importance of Coffee production and productivity of crop is still limited due to post-harvest handling and processing problems. Coffee processing is aimed to lower the water content of fresh cherries to a level which allows the preservation of beans (about 11-12 %), removing all the covering which surround the beans and preparing the beans according to market requirements. Unintentional or intentional harvesting of cherries at several stages of maturation may have adverse impacts on coffee quality if these materials are processed together. Cherries at different stages of maturation should be separated and processed using different techniques in order to retain as much quality as possible. Cherries must undergo dry, semi-dry or wet processing as soon as possible after harvesting. The storage of fresh cherries in bags, heaps, hoppers or silos should not last more than eight hours. Otherwise unwanted fermentation will generate the dreaded “stinker” beans, which appear when the temperature before pulping exceeds 40-42°C. Even if the temperature does not rise to the point of creating stinkers, uncontrolled fermentation may have other negative impacts on the cup. Coffee cherries should not be kept in plastic bags. The damp airtight atmosphere that develops inside plastic bags favors unwanted fermentation that damages coffee quality. Therefore, the main objective of this paper is to review on post-harvest and green bean coffee processing in Ethiopian. Keywords: Green Coffee, Post harvest, Processing DOI : 10.7176/JNSR/9-9-05 Publication date :May 31 st 2019

Draft Genome Sequence of Pediococcus acidilactici Strain LPBC161, Isolated from Mature Coffee Cherries during Natural Fermentation.

Here, we report the draft genome sequence of Pediococcus acidilactici strain LPBC161, a lactic acid bacterium isolated from mature coffee cherries in Brazil. The genome sequence of P. acidilactici LPBC161 provides valuable information on the mechanisms of adaptation and metabolism of lactic acid bacteria (LAB) in the environment and stressor factors of coffee processing.

Pengaruh Lama Perendaman Buah dan Fermentasi terhadap Warna Kulit Tanduk dan Citarasa Kopi Robusta

<em>Pulping and fermentation of coffee cherry determine the quality of green beans and coffee flavors. Delay in pulping will cause the slime stick to the hull skin hence decreasing the bean quality and flavor. The objective of this study was to examine the effect of soaking before pulping and fermentation time to the color of coffee hull skin and the cup quality. The research was carried out at the experimental station of Indonesian Coffee and Cocoa Research Institute in Malang Regency (ICCRI) and ICCRI laboratory in Jember Regency from July 2018 to January 2019. Experiments used factorial completely randomized design. The first factor was cherry soaking duration (0, 24, 48, and 72 hours) and the second factor was fermentation duration (0, 24, and 48 hours) and then combined into 12 treatments, with three replications. Ten kilograms of coffee cherries were soaked prior to pulping then fermented in a plastic bag and added with </em>Lactobacillus casei<em> 2,5 x 10<sup>7</sup></em><em> cfu/ml as starter. Parameters observed were color of hull skin </em>(<em>L</em><em> value</em>, <em>a*</em><em>, dan b*) and the cup quality. The results showed that soaking the cherry decreased the green beans quality which is indicated by less brightness (L), high a* value, and decreasing b* value of hull skin color. While the fermentation treatment can increase the value of L, decrease the a* value, and increase the b* value. The interaction of treatment of soaking and fermentation time significantly affected the lightnessl a* and b* value. Soaking and fermentation treatments did not significantly affect to the flavor, salt/acid, balance, and total score of coffee flavor. Soaking is not recommended for more than 48 hours and fermentation should be carried out 48 hours.</em>

The Role of Microbes in Coffee Fermentation and Their Impact on Coffee Quality

Coffee is one of the most important and widely used commercial crops in the world. After ripe coffee cherries are harvested, coffee must pass through several steps to become (green) raw coffee beans. Commonly, there are three different processing methods used to obtain green coffee beans from coffee cherries, namely, the wet, dry, and semidry methods. Microorganisms (yeasts and bacteria) play a major role in coffee fermentation process by degrading mucilage by producing different enzymes (pectinase), acids, and alcohols. Starter culture development is crucial and is done by selecting microorganisms that have certain characteristics, such as mucilage degradation ability, tolerance to stress during fermentation, the ability to suppress the growth of pathogenic fungi, and a positive impact on the sensory quality of the coffee. Currently, green coffee beans obtained from farms that use any of the above processing methods are fermented with selected microorganisms to improve the flavour and aroma of the coffee. This is the result of a new insight into the development of unique flavoured coffee and into engaging with the coffee market to better benefit. This review gives a comprehensive overview of the fermentation process, microorganisms and starter cultures, and fermentation’s impact on coffee quality. Future prospects are also discussed through the incorporation of recent research.

Following Coffee Production from Cherries to Cup: Microbiological and Metabolomic Analysis of Wet Processing of Coffea arabica.

A cup of coffee is the final product of a complex chain of operations. Wet postharvest processing of coffee is one of these operations, which involves a fermentation that inevitably has to be performed on-farm. During wet coffee processing, the interplay between microbial activities and endogenous bean metabolism results in a specific flavor precursor profile of the green coffee beans. Yet, how specific microbial communities and the changing chemical compositions of the beans determine the flavor of a cup of coffee remains underappreciated. Through a multiphasic approach, the establishment of the microbial communities, as well as their prevalence during wet processing of Coffea arabica, was followed at an experimental farm in Ecuador. Also, the metabolites produced by the microorganisms and those of the coffee bean metabolism were monitored to determine their influence on the green coffee bean metabolite profile over time. The results indicated that lactic acid bacteria were prevalent well before the onset of fermentation and that the fermentation duration entailed shifts in their communities. The fermentation duration also affected the compositions of the beans, so that longer-fermented coffee had more notes that are preferred by consumers. As a consequence, researchers and coffee growers should be aware that the flavor of a cup of coffee is determined before as well as during on-farm processing and that under the right conditions, longer fermentation times can be favorable, although the opposite is often believed.IMPORTANCE Coffee needs to undergo a long chain of events to transform from coffee cherries to a beverage. The coffee postharvest processing is one of the key phases that convert the freshly harvested cherries into green coffee beans before roasting and brewing. Among multiple existing processing methods, the wet processing has been usually applied for Arabica coffee and produces decent quality of both green coffee beans and the cup of coffee. In the present case study, wet processing was followed by a multiphasic approach through both microbiological and metabolomic analyses. The impacts of each processing step, especially the fermentation duration, were studied in detail. Distinct changes in microbial ecosystems, processing waters, coffee beans, and sensory quality of the brews were found. Thus, through fine-tuning of the parameters in each step, the microbial diversity and endogenous bean metabolism can be altered during coffee postharvest processing and hence provide potential to improve coffee quality.

Good to the last drop: The emergence of coffee ringspot virus.

Two and a half billion times per day a human hand reaches for a fresh cup of coffee. Although arguably dispensable for life per se, with an industry value of US$174 billion, coffee provides the lifeblood that sustains economies of producing countries located in the “coffee belt” situated between the Tropics of Cancer and Capricorn. As a “solvent” in which many human interactions take place, coffee is witness to the broad spectrum of human activities from the mundane to the pleasurable and personal. However, in opposition to its economic, cultural, and physiological importance, diseases such as coffee rust (caused by the fungus Hemileia vastatrix) dictate activity on stock markets with their periodic epidemics, which in turn affects the migration patterns of displaced farm workers [1]. Other diseases, such as those caused by coffee ringspot virus (CoRSV), currently fly mostly under the radar of many integrated pest management systems. The unique biology of this and related viruses offers exciting research opportunities ranging from cell biology, plant pathology and physiology, conservation ecology, to climate change-related epidemiology. This review highlights important aspects of CoRSV, including its unique features, and examines the potential role of climate change in its emergence (Fig 1). Open in a separate window Fig 1 Diverse array of research projects related to understanding the effect of CoRSV on coffee. (A) Whether enjoyed alone or in the company of others, coffee is an integral component of daily life in all countries around the world. Only one small-scale study has been done to determine the effect of CoRSV on coffee quality [34]. (B) The effect of CoRSV on the yield of coffee plants has not been examined. (C) No formal investigations have been made to determine how CoRSV influences the development of coffee cherries. (D) Only one study has investigated the population structure of CoRSV [8, 35]. It remains to be determined if phylogenetic trees derived from different CoRSV genes or from viral RNA isolated from plants or mites are congruent. Furthermore, evidence for recombination or reassortment of CoRSV genomes has not been investigated in detail. (E) The reservoir of CoRSV in wild species, particularly in the Cerrado of Brazil, has not been investigated. It is unknown if the population structure of CoRSV in the wild is similar to that in coffee plants. (F) The molecular basis for temperature dependent susceptibility to systemic infections has not been determined [23]. (G) The cell biology of CoRSV beyond generation of protein interaction and localization maps is poorly characterized, particularly with respect to identification of host factors required for replication and cell-to-cell movement, viroplasm formation, and nucleocytoplasmic trafficking of CoRSV nucleocapsids and proteins [23]. CoRSV, coffee ringspot virus; NPC, nuclear pore complex; VP, viroplasm; XPO1, Exportin 1.

Direct-infusion electrospray ionization-mass spectrometry analysis reveals atractyligenin derivatives as potential markers for green coffee postharvest discrimination

Coffee quality is strongly related to postharvest processes. Dry and wet are the most traditional and employed processes. However, more recently, the semi-dry process has been introduced and applied for producing coffees of good quality in a more environmental friendly manner compared to the wet process. In this work, green Arabica coffee cherries from two consecutive crops were submitted to the dry and semi-dry postharvest processes and their methanol:water extracts were characterized by ESI(−) FT-ICR MS followed by chemometric data analysis. Thirty-three compounds were identified in the extracts by their high-resolution and accurate m/z values and MS/MS spectra being nine of them diterpenes related to atractyligenin derivatives. The dry and semi-dry processes led to distinct extracts in which compounds such as atractyloside II, carboxyatractyloside II and carboxyatractyloside III showed the greatest contributions (p < 0.05) based on t-Student's test and PLS-DA statistical analyses. These compounds were able to discriminate the postharvest processes for coffees from two consecutive crops. These results can help to better understand the effects of the postharvest processes in the final chemical composition and coffee quality.

Effect of Soil Management Practices on the Sweeping Operation during Coffee Harvest

Core Ideas The harvest performance can be affected by plant phenological behavior, non‐uniform fruit ripening, late harvest, pests and diseases, rods vibration intensity, displacement velocity and, finally, slope. After harvesting, the approximately 10–20% of coffee cherries that fall on the ground are known as the sweeping coffee and require a gathering operation. The mechanical sweeping and gathering allow higher operational capacity (working greater areas in shorter times), thus increasing profitability and reducing operational costs, however, these machines are sensitive to oscillation and/or soil topography. In addition to this limiting factor, one of the main obstacles to mechanical picking of sweeping coffee is the subsoiling operation that consists of unpacking the soil by moving the soil surface of the coffee interlines, where the coffee berries are to be harvested later . In this context, assuming that the subsoiling operation could affect the losses during the mechanical picking of sweeping coffee, this study aimed at using the SPC tools to monitor the ability of management processes to reduce losses in the sweeping and mechanical picking of fallen coffee for four soil managements. The mechanical sweeping and picking of coffee berries are necessary to recover berries that naturally fall on the soil during the mechanical harvesting process. The soil characteristics and the materials that are collected affect these two operations; in addition, there are reports that suggest that mechanical sweeping and picking are hampered by subsoiling. In this regard, the current study evaluated losses during the mechanical sweeping and picking of coffee cultivated under four soil management treatments in Presidente Olegário, MG, Brazil. The four treatments consisted of the following soil management practices: subsoiling and crushing; subsoiling and harrowing; subsoiling followed by harrowing and crushing; and the control, with no soil management. The soil was prepared in 2014, while the coffee sweeping and picking occurred in 2015 and 2016. The experimental design followed the assumptions of statistical process control, and fifteen points were evaluated per treatment in accordance with the statistical process control guidelines. The lowest loss rates were obtained for the subsoiling and crushing soil management treatment, whereas harrowing after subsoiling led to the highest losses and the lowest process quality.

Volatile and sensory characterization of roast coffees – Effects of cherry maturity

Immature coffee cherries produce roast coffees with lower hedonic scores than those produced from mature cherries, but variation in volatile and sensory characteristics over a range of maturities is not well studied. In this work, cherries from two coffee cultivars (Caturra, Catimor) were sorted into seven maturity stages from fully immature (Stage 1, green) to fully overripe (Stage 7, purple). Volatile profiles of Stage 1 roast coffee had lower concentrations of carbohydrate degradation products and higher concentrations of N-heterocycles and phenols. Differences in volatiles among Stage 2 (partially immature, yellow-green) and subsequent stages were insignificant (p > 0.05) or else minor. Principle component analysis of the volatile data set also distinguished Stage 1 from other stages. Similarly, a trained cupping panel reported significantly lower sensory scores for Stage 1 as compared to Stages 2–7, but few differences among Stages 2–7. Thus, partially mature and overripe cherries may be appropriate for specialty coffee.

Potential of lactic acid bacteria to modulate coffee volatiles and effect of glucose supplementation: fermentation of green coffee beans and impact of coffee roasting.

Coffee flavor can be significantly influenced by microbial activities in spontaneous fermentation of coffee cherries. The potential of lactic acid bacteria for flavor modulation through controlled fermentation of green coffee beans has not been explored. Fermentation by Lactobacillus rhamnosus HN001 with and without 1% w/w glucose supplementation led to modification of flavor-related constituents in green coffee beans, which translated into modulation of coffee volatiles upon roasting. The lactic acid bacteria consumed almost all glucose and fructose, leaving sucrose behind. Amino acids and malic, citric, and succinic acids were partially catabolized. Glucose supplementation enhanced lactic acid production but repressed acetic acid formation. After roasting at 235 °C for 9min, 12 min, and 15 min, the levels of furfurals in glucose-supplemented-fermented coffee were 10.5-, 2.7-, and 1.1-fold higher than those in the controls (nonsupplemented-unfermented coffee); furthermore, the levels of pyrazines in the controls were 11.9-, 10.1-, and 6.5-fold higher than those in the treated coffee. Glucose-supplemented fermentation yielded roasted coffee with stronger caramelic and burnt characteristics but weaker nutty notes. In roasted non-supplemented-fermented coffee, volatile production was generally reduced, resulting in a milder overall aroma. Lactic acid fermentation of green coffee beans is a new strategy for coffee flavor modulation, creating novel aroma characteristics. © 2018 Society of Chemical Industry.

English

This study assesses the effect of cooperative, certification, private trader, farmers, sorting and processing methods on Arabica coffee quality. Coffee samples were collected from certified cooperatives, non-certified cooperatives, private traders and farmers (members of certified cooperatives, non-certified cooperatives and non-members of cooperatives). The study showed that coffee beans sampled from cooperatives had higher quality scores and were classified as specialty 1 (Q1) (33%) or specialty 2 (Q2) (67%). About 78% of coffee beans sampled from private traders fall in grade 3, while 22% of their beans qualified for Q2. Coffee certification, in general, did not add any value to coffee quality. No quality differences were also observed between coffee beans sampled from farmers. Coffee quality differences were observed between coffee processing methods. Dry processing method improved coffee quality. However, this can only be achieved by using ripe red cherries. Cherry sorting also improved coffee quality and the percentage of coffee samples that fall in Q1. In general, proper coffee cherries type together with site specific coffee processing approach helps coffee actors to produce high quality coffee. Key words: Arabica coffee, flavor, body, specialty, cherry, acidity.

Bio-succinic acid production from coffee husk treated with thermochemical and fungal hydrolysis.

Coffee husk (CH), a waste obtained from processing of coffee cherries via dry method, causes serious environmental problems. In this study, strategies were designed to utilize CH for succinic acid (SA) production. Three different CH hydrolysis methods: thermal, thermochemical and crude enzymes obtained by solid state fermentation of Aspergillus niger and Trichoderma reesei, were evaluated to generate fermentable feedstock for SA production using Actinobacillus succinogenes. The feasibility of these pretreatment methods was investigated. Accordingly, thermochemical hydrolysis using H2SO4 at 121°C for 30min, appeared the most effective method for CH hydrolysis, producing 24.4g/L of reducing sugars (RS). Finally, 19.3g/L of SA with yield and productivity of 0.95g SA/g RS and 0.54g/L/h, respectively, were obtained using CH hydrolysate. The current study revealed an alternative way of utilization coffee waste for value addition while mitigating environmental problems caused by its disposal.

Comparison of Value-Added Analysis of Coffee Processing with Different Market Orientations: (Case Study on Cooperative of Producer Coffee Margamulya)

Cooperative of Producer Coffee Margamulya (CPCM) consists of 140 members who produced Arabica java preanger coffee with an average of 70 tons green bean per year. The cherry coffee is first processed into green bean using wet processing method before being sold. Eighty percent of green beans are marketed to exporters (PT. Taman Delta Indonesia / PT. TDI) while 10% to Indocom and the other 10% to various markets with various products. This study was more focused on the analysis of difference of added value obtained by cooperatives from the dominant market for green bean, i.e., to exporters and Indocom. Also, this study aimed to determine the factors that influence market selection. The method used was a case study, with Hayami value-added analysis technique. The result showed that the added value of cherry processing became green bean for the export market was 19% while the value added for Indocom was 34%. The reason for choosing the market to exporters is that PT. TDI receives a large number of green beans, and provides UTZ (utilize) certification assistance. On the contrary, Indocom only bought smaller volumes than PT. TDI with non-fixed frequencies.

Efecto de cuatro inhibidores de etileno en la maduración del fruto de café (Coffea arabica L.) durante precosecha

En el proceso natural de maduración de los frutos climatéricos, se puede modificar e intervenir los mecanismos de acción del etileno durante precosecha y poscosecha. En algunos frutos los inhibidores del etileno han permitido retardar su desarrollo. En esta investigación se evaluó el efecto de cuatro inhibidores de etileno en el desarrollo de frutos de café durante precosecha. En la Estación Experimental Paraguaicito de Cenicafé (04°23´ N y 75°44´ W, Quindío, Colombia) en un cultivo de café variedad Castillo® Paraguaicito, se instalaron bajo un diseño de bloques completos al azar 13 tratamientos correspondientes a cuatro inhibidores de etileno que fueron acetato de potasio (0,5; 1,0 y 2,0% P/V), ácido aminooxiacético (1, 5 y 10 mg L-1), ácido salicílico (1, 5 y 10 mM) y aminoetoxi-vinil-glicina (25, 50 y 100 μg L-1) en tres diferentes dosis, además de un testigo absoluto. Los inhibidores se aplicaron 1 semana antes del pico de cosecha y 4 semanas después. Se evaluaron las variables producción de café cereza, peso de un fruto, frutos caídos y el porcentaje de frutos inmaduros, pintones, maduros y sobremaduros. Esto se realizó en la cosecha principal de 2016 y la cosecha secundaria de 2017. En la cosecha principal, los tratamientos aminoetoxi-vinil-glicina (100 μg L-1) y ácido salicílico (1 mM) retardaron el proceso de maduración al reducir entre 16,0 y 16,6% el porcentaje de frutos sobremaduros y aumentar entre 12,8 y 14,3% el porcentaje de frutos maduros, respecto al testigo absoluto. En la cosecha secundaria, los tratamientos y el testigo no difirieron significativamente en ninguna de las variables evaluadas.

Determination of the complex permittivity of cherry, pulped, green, and roasted coffee using a planar dielectric platform and a coaxial probe between 0.3 and 6 GHz

ABSTRACTThe complex permittivity for four processing stages of coffee: coffee cherries, pulped coffee, green coffee, and roasted coffee was obtained and divided into two groups. The wet group is constituted by cherry and pulped coffee, and the dry group by green and roasted coffee. The wet group presented a dielectric constant between 64 and 43, and a loss factor between 34 and 12. The dry group has values oscillating between 1.55 and 1.1 for the dielectric constant, and 0.037 and 0.005 for the loss factor. The permittivity difference between the wet and dry groups suggests the dependence of the coffee permittivity on the water content, along with the presence of other polar compounds. A decaying response for the dielectric constant was seen, with a proportion of 30:1 from the wet to the dry group. The loss factor presents a convex response for the wet group and a constant response for the dry group with a factor of 500 to a 100:1 from the wet to the dry group. A set of 18 samples at every stage was used to estimate the moisture content by partial least squares. The Meyer and Schilz coefficient was used for these models, that resulted in prediction errors of 2.8% and 3.8% when compared to the stage mean moisture content for the wet group. The dry group resulted in errors of 21% and 89.7%. These results indicate that the complex permittivity of coffee is capable of estimating physicochemical variables as the moisture content of the beans at distinct processing stages.