Seleção de novas cepas de leveduras para fermentação de cafés arabica (Coffea arabica L.) e conilon (Coffea canephora P.)

Abstract

Coffee is the most consumed non-alcoholic beverage in the world and Brazil is the largest producer and one of the largest exporters of it. There is a great diversity of microorganisms naturally present in coffee, such as bacteria, fungi and yeasts that can beneficially influence the final quality of the product. In this work, new yeast strains were evaluated for possible use as starter cultures in arabica and conilon coffees. A total of 56 strains of the species were evaluated Cystofilobasidium ferigula (10), Rhodotorula mucilaginosa (5), Debaryomyces hansenii (1), Wickerhamomyces anomalus (4), Hanseniaspora uvarum (7), Hanseniaspora opuntiae Čadež (2), Pichia kluyveri (2), Pichia fermentans (2), Meyerozyma guilliermondii (6) and Meyerozyma caribbica (17). Enzyme tests were carried out to evaluate the activity of pectin lyase and polygalacturonase in the strains and, in the end, 34 were selected that showed better enzymatic activity. Fermentation in coffee husk and pulp medium was carried out to evaluate the growth and also the organic and volatile compounds obtained from the fermentation with different strains. The techniques of high-performance liquid chromatography and gas chromatography with mass spectrometer were performed to characterize the profile of organic acids and volatile compounds. The growth of strains in the last fermentation time was around 107CFU/mL for arabica and conilon coffee. The organic compounds detected were malic, citric and succinic acid. The strains: Meyerozyma guilliermondii CCMA1737 and Meyerozyma caribbica CCMA1993, Meyerozyma caribbica CCMA1617, Meyerozyma caribbica CCMA1992, Meyerozyma caribbica CCMA1950, Meyerozyma caribbica CCMA1735, Pichia kluyveri CCMA1658, Cystofilobasidium ferigula CCMA1647, and Hanseniaspora uvarum CCMA1944 were selected as potential starter cultures for Arabica coffee. The strains: Hanseniaspora uvarum CCMA1895, Rhodotorula mucilaginosa CCMA1663, Pichia kluyveri CCMA1652, Meyerozyma caribbica CCMA1950, Hanseniaspora uvarum CCMA1944 were selected as potential initiator cultures for conilon coffee. In addition, the behavior of potential starter cultures should be evaluated during the fermentation process of arabica and conilon coffee.