Avaliação da performance fermentativa de cepas de leveduras e bactérias do ácido lático durante o processamento úmido do café

Abstract

The wet fermentation of coffee using the self-induced anaerobic fermentation methodology by microbial metabolism (SIAF) has proven to be an alternative in the production of specialty coffees, providing distinct and complex characteristics. The objective of this study was to evaluate the influence of yeast inoculation (Saccharomyces cerevisiae CCMA0543, Torulaspora delbrueckii CCMA0684, Hanseniaspora uvarum CCMA0236, and Pichia kluyveri CCMA0237) and lactic acid bacteria (Leuconostoc mesenteroides CCMA1105 and Lactiplantibacillus plantarum CCMA1065), both individually and in co-culture, during the wet fermentation of coffee using SIAF. Carbohydrates, bioactive compounds, and organic acids were analyzed by high-performance liquid chromatography (HPLC), volatile compounds were detected by gas chromatography-mass spectrometry (GC/MS), and sensory analysis was conducted through cupping tests. During the process, carbohydrates present in the fruits were metabolized (78.3%) by bacteria and yeast, resulting in the production of metabolites such as organic acids and volatile compounds, which had a significant impact on the final quality of the product. Additionally, volatile compounds from different classes were identified, such as acids, esters, alcohols, ketones, pyrazines, and furans, both in green coffee samples and roasted coffees, contributing to the sensory profile of the beverage. All the coffees resulting from these fermentations were classified as specialty coffees (>80 points). It is important to emphasize that the different inoculations performed provided distinct sensory descriptors, which increased the complexity and diversity of the beverage's characteristics. The co-inoculation of H. uvarum CCMA0236 and L. plantarum CCMA1065 showed higher concentrations of volatile compounds after fermentation (52.32 mg.kg-1), and the inoculation using H. uvarum CCMA0236 obtained a higher concentration of volatiles after roasting (2057.6 mg.kg-1). The co-inoculation of H. uvarum CCMA0236 and L. plantarum CCMA1065 showed a higher sensory score (81.59). The co-inoculation of S. cerevisiae CCMA0543 and L. plantarum CCMA1065 contributed greater complexity to the beverage, with sensory descriptors of honey, brown pepper, nutmeg, and cinnamon. Therefore, the wet fermentation of coffee fruits, using the inoculation of lactic acid bacteria and yeast through the SIAF methodology, presents itself as an innovative and promising approach to enhance the quality of produced coffees, exploring new sensory profiles, and adding value to the products.