| Congresso Brasileiro de Microbiologia 2023 | Resumo: 826-1 | ||||
Resumo:The drying process can be used for the long-term preservation of epiphytic coffee yeasts, contributing to storage, transportation, reducing odor, and the possibility of contamination. Thus, this work aimed to evaluate the behavior of microencapsulated yeasts in coffee peel and pulp medium (CPM). Saccharomyces cerevisiae CCMA0543, Torulaspora delbrueckii CCMA0684, and Meyerozyma caribbica CCMA1738 were microencapsulated by spray drying. Fermentation was carried out in a CPM medium. Coffea arabica was used for fermentations with S. cerevisiae and T. delbrueckii, and Coffea canephora was used for M. caribbica. Six treatments were performed: fresh S. cerevisiae (FS), T. delbrueckii (FT) and M. caribbica (FM), and microencapsulated S. cerevisiae (MS), T. delbrueckii (MT) and M. caribbica (MM). Yeasts were inoculated separately at 107 CFU/mL concentrations for 48h. Population count, pH, and Brix were measured throughout the fermentation. Sugars, alcohol, and organic acids were evaluated by high-performance liquid chromatography (HPLC). The yeasts' specific growth rate and generation time were also evaluated in the CPM medium. FS and FT showed higher specific growth rates and shorter generation times than fresh ones, with differences of up to 66%. However, MM showed a higher growth rate (15%) and shorter generation time (15%) than FM. After 48 hours of fermentation, there was no difference in population counts between fresh and microencapsulated yeasts, ranging from 9.1x107 to 1.38x108 CFU/mL. The pH decreased from 5.5 to 4.0 and Brix from 5.0 to 1.0 °Brix. Sucrose, glucose, and fructose were analyzed as total reducing sugars (TRS). Ethanol and citric, malic, and succinic acids were detected in all fermentations. S. cerevisiae showed no statistical difference in ethanol and succinic acid production. MS showed higher consumption of TRS (0.07 g/L) and higher malic acid production (0.25 g/L). However, T. delbrueckii did not show statistical differences only for ethanol production. MT had higher TRS consumption (0.023 g/L) and higher malic acid production (0.87 g/L). Finally, M. caribbica showed no significant difference in citric and malic acids. MM showed higher production of ethanol (0.61 g/L) and succinic acid (0.67 g/L). Therefore, some differences were found in the fermentation of the CPM medium. However, microencapsulated yeasts maintained their biotechnological characteristics and could be promising in coffee fermentation.
Palavras-chave: coffee fermentation, HPLC, spray drying, organic acids Agência de fomento:CAPES; CNPq; FAPEMIG; Syngenta Proteção de Culturas Ltda | |||||