Characteristics of fermented coffee inoculated with yeast starter cultures using different inoculation methods

This study aimed to evaluate the behavior of yeasts as starter cultures for dry processed coffee. Saccharomyces cerevisiae CCMA 0543, Candida parapsilosis CCMA 0544, and Torulospora delbrueckii CCMA 0684 were separately inoculated into coffee by directly spraying the cherries on a terrace or in buckets for 16 h before sun drying. Samples were collected and analyzed by qPCR (inoculum persistence), HPLC and GC-MS. Sensory analysis was performed on the roasted coffee. All treatments directly inoculated with yeasts showed high citric and malic acid concentrations. Caffeine, chlorogenic acids and trigonelline concentrations varied between the methods of inoculation. A total of 217 volatile compounds were identified. After roasting, volatile compounds corresponding to caramel flavor were detected in samples inoculated with Saccharomyces cerevisiae CCMA 0543 D. Fruity flavor (apple, cherry) compounds were observed in samples inoculated with Candida parapsilosis CCMA 0544 D. Saccharomyces cerevisiae CCMA 0543 inoculated in buckets obtained the highest score in the coffee cupping. Direct inoculation of Candida parapsilosis CCMA 0544 showed the best results when compared to the bucket method, while Torulospora delbrueckii CCMA 0684 showed good results for both inoculation methods evaluated.