Inclusion of autochthonous and allochthonous microbial starters in wet fermentation processes of Coffea arabica L.

Abstract

All around the world, specialty coffees submitted to fermentation gain economic prominence in the coffee trading sector. This study used two cultivars of Coffea arabica L. growth by Agência Paulista de Tecnologia dos Agronegócios (APTA) on Marilia region (midwest region of São Paulo state, Brazil): cultivar yellow Topázio MG 1190 (YTPMG) and cultivar red Catuai IAC 144 (RCIAC). Both cultivars were submitted to wet fermentation processes in order to: 1) observe the influence of starter cultures and 2) to describe their microbiological and sensorial performances. Sensorial findings were respectively compared to their non-fermented and naturally fermented samples.  Equal portions of YTPMG and RCIAC cherries were distributed into different buckets containing 20 L of potable water each, leading to two experiments with 5 treatments, of which T1 was natural fermentation and the others received different combinations of autochthonous or allochthonous yeasts, besides species of commercial lactic bacteria. Laboratorial evaluation included: pH, temperature, soluble solids and microbiological analysis. Sensorial analyses were conducted by experts and Q-graders. The sensory data were submitted to statistical analysis. After 46 h under wet fermentation, the counts of “good” micro-organisms (M.O.) enhanced (yeasts and lactic bacteria) and the “bad” M.O. reduced (enterobacteria), resulting in differentiated aroma among the coffees treatments. Lactic bacteria starters (SACCO Brasil) stimulated yeasts growth during fermentation, while Lactobacillus plantarum (LEMA) inhibited. All the fermented coffee were graded as specialty coffees, reaching more than 80 points, and the highest notes referred to the treatments that included lactic bacteria starters. YTPMG had better cupping notes than RCIAC. Cupping notes were lower than 80 for all non-fermented coffees, indicating that the technology of controlled fermentation including starter cultures is able to ensure exquisite sensorial values and a better placing in the highly competitive market.