Fermentation of Coffea canephora inoculated with yeasts: Microbiological, chemical, and sensory characteristics.

This work aimed to evaluate Coffea canephora's microbiological, chemical, and sensory characteristics at 300 and 600 m elevation plantations processed by the natural method inoculated with yeasts. The coffee was spread on suspended terraces and sprayed with approximately 107 cfu/mL of Meyerozyma caribbica CCMA 1738 or Pichia kluyveri CCMA 1743, separately. Cherries containing bark and parchment were collected during fermentation for microbial groups counting, qPCR, quantification of organic acids, and sugars (HPLC). Volatile compounds (GC-MS) and sensory analyses, cupping test with expert coffee tasters and triangular test with consumers, were performed on roasted coffee beans. The inoculated yeasts persisted during the entire fermentation process. M. caribbica reduced the filamentous fungal population by 63% and 90% in the 300- and 600-m coffees, respectively. The 300-m coffee fruits showed higher concentrations of organic acids in all fermentation times when compared to the 600-m reaching out to 8 times more. Twenty-four volatile compounds were identified in the roasted coffee beans, with the predominance of pyrazines. The 600-m coffee inoculated with M. caribbica showed an increase of more than one point in the score given by certified tasters. Consumers noticed the M. caribbica inoculation in the 300- and 600-m-elevation coffees. M. caribbica is a promising starter culture for Conilon coffee with the potential to increase the beverage quality.

Microbial diversity and chemical characteristics of Coffea canephora grown in different environments and processed by dry method.

This study aimed to assess the microbial diversity in Coffea canephora grown in four different environments of Espirito Santo state, Brazil. Coffee cherries of two different altitudes (300 and 600 m) and two terrain aspects (Southeast-facing and Northwest-facing slopes) were processed by the dry method. Samples were collected during the drying/fermentation process. Microorganisms were counted, isolated, and identified by MALDI-TOF, followed by sequencing of the ribosomal region. Sugars and organic acids were quantified by HPLC and volatile compounds of the roasted coffees were evaluated by GC-MS. Bacteria population presented a significant number of isolates as well as higher counts during the drying/fermentation process with respect to the population of yeasts. The principal genera of microorganisms found were Bacillus, Pichia, Candida, and Meyerozyma. Meyerozyma guilliermondii was the most frequent yeast in all environments. On the other hand, Pichia kluyveri was found only in coffee cherries from the 600 m altitude. The highest concentration of acetic and succinic acids observed was 6.06 mg/g and 0.84 mg/g, respectively. Sucrose concentrations ranged from 0.68 to 5.30 mg/g, fructose from 1.30 to 4.60 mg/g, and glucose from 0.24 to 1.25 mg/g. Thirty-six volatile compounds, belonging to the groups of pyrazines, alcohols, aldehydes, ketones, and furans were identified in roasted coffee, with differences between altitude and terrain aspects. Information about microbial diversity is crucial to better understand the coffee quality and distinct characteristics of coffee produced in different environments.

Effect of altitude and terrain aspect on the chemical composition of Coffea canephora cherries and sensory characteristics of the beverage.

BACKGROUND: The terrain slope and field altitude where the plant is cultivated influence the composition of coffee cherries. The aim of this study was to analyze the effects of different levels of altitude and terrain slope on the Coffea canephora cherries, as well as on the quality of the final beverage. C. canephora harvested in fields with 300 and 600 m altitude and with southeast- and northwest-facing slopes was evaluated. RESULTS: Lower pH values were observed for cherries cultivated at higher altitudes. The highest percentage of soluble solids (525.00 g kg-1 ) was found on northwest-facing slopes at 300 m. The highest values of phenolic compounds were observed at 600 m. Significant differences were found in the moisture of coffee cherries grown in different terrain slope and in the fiber content at different altitudes. The results do not enable us to conclude how the altitude and terrain slope influence the mineral content of cherries. Acidity, proteins, lipids, and carbohydrates were not influenced by altitude or terrain slope. The scores of cup quality were significantly affected by the altitude but not by the terrain slope. Coffees from cherries harvested in fields with 600 m altitude obtained the higher scores. CONCLUSION: Results show that altitude and terrain slope influence some compounds of coffee fruits, whereas others remain unaffected. The findings are important because, during coffee fruits processing, these compounds are used to produce others that will have an influence on the bean and coffee beverage quality. © 2020 Society of Chemical Industry.