Avaliação da microbiota presente no processamento úmido do café e do uso de culturas iniciadoras no processamento natural e semi-seco

Abstract

Coffee is among the most consumed beverages and is a product of great importance for economy in Brazil, the main producer and exporter. There is a microbial flora present in coffee composed by yeast, fungi and bacteria. During the processing of the fruits, the metabolic activity of this natural microbial flora may influence the final quality of the product. The present work aimed at evaluating the use of yeast as initiating culture in the natural and semi-dry processing of coffee, as well as come to know the microbial flora present during the humid processing. Dependent and independent cultivating methods (PCR-DGGE) were used to evaluate the microbial flora. The chromatographic techniques – high performance liquid chromatography (HPLC) and gas chromatography (GC) were used to characterize the profile of volatile acids and compounds. The Temporal Dominance Sensations (TDS) methodology was used in the sensorial analysis. The use of initiating cultures in the semi-dry processing of coffee showed to be an alternative to obtain a differentiated product. The propionic and butyric acids, which may compromise the sensorial characteristics, were not detected, and the presence of initiating cultures promoted a higher concentration of volatile products on toasted coffee and provided a caramel flavor, with the best results being obtained for Candida parapsilosis UFLA YCN448 and Sacchatomyces cerevisiae UFLA YCN727. During the humid processing of the coffee it was possible to identify a large variety of yeast species, the main species being Pichia caribbica (53%), Hanseniaspora uvarum (35.57%), Torulaspora delbrueckii (50%), and of bacterias, the main species being Staphylococcus warneri, Erwinia persicina (19.61%), Enterobacter asburiae (41.80%) and Leuconostoc mesenteroides. The use of the DGGE technique combined with the dependent cultivation method was necessary to obtain a better evaluation of the microorganism species present during coffee fermentation.