Influence of altitude on the microbiota and on the sensorial and chemical quality of fermented coffee (Coffea arabica L.) from Serra do Caparaó, ES region

Abstract

The variations in the sensorial profile of coffee produced in different countries or regions are notorious. The microbiota and grain quality are influenced by several environmental factors such as temperature, rainfall, wind, sun exposure, soil type and topography. Besides that, there are climatic factors associated to the change of altitude, such as atmospheric pressure, temperature, oxygen and CO2. The objective of this work was to evaluate the influence of coffee fruits cultivated at different altitudes (800, 1000, 1200, 1400 m) on the microbiota and how these two factors may influence the chemical and sensorial quality of the final beverage of fermented coffees (Coffea arabica L.) grown in Serra do Caparaó, Espírito Santo, Brazil. Mature fruits were collected at different altitudes, manually selected and fermented in bioreactors located at an altitude of 1200 m. Pulped and natural processes were performed in triplicate and fermented by 72 h. The grains were sun-dried on suspended terraces at until reaching 11-12% moisture. For microbiological analysis, the population count of bacteria and yeasts was performed from surface plating. The isolates were grouped and identified from the ionization and desorption techniques assisted by matrix - flight time (MALDI-TOF) and sequencing of the ribosomal region using specific primers for each microbial group. The chemical compositions were evaluated by Raman spectroscopy and the sensorial analysis was realized using the Temporal Dominance of Sensations (TDS) methodology. There was a significant difference in the population count of the microorganisms studied between the altitudes and between processing. The chemical composition and sensory perceptions of the beverage were also influenced by altitude and processing. The coffee cultivated at an altitude of 1400 m was the most appropriate in both processes. Altitudes of 800 and 1200 m were more efficient in pulped coffee and 1000 m in natural coffee. Altitude is a factor that influences the chemical composition of the grain, the natural microbiota presents in the fruit and, consequently, the sensorial perception of the fermented coffees.