Microbial modulation of Catharina sour beer: Effects of indigenous lactic acid bacteria and yeasts on chemical composition and sensory attributes.

Catharina Sour beer is the first Brazilian beer style to gain international recognition. The style typically involves sequential fermentation with lactic acid bacteria and yeast, as well as the addition of tropical fruits. This study aimed to evaluate the fermentative performance of indigenous strains of Lactiplantibacillus plantarum and Saccharomyces cerevisiae and their impact on the chemical and sensory profile of Catharina Sour beer with acerola (Malpighia emarginata). Wort fermentation was carried out in batches using Lpb. plantarum CCMA 0743 in combination with previously selected yeast strains (S. cerevisiae CCMA 0200, CCMA 0233) and a commercial strain SafAle™ S-04. After fermentation, 20% acerola pulp was added, and the beers were cold-aged and carbonated. Microbial population dynamics, physicochemical parameters, organic acid (HPLC), and volatile compounds (GC-MS) were monitored throughout fermentation. After 12 h of fermentation, Lpb. plantarum CCMA 0743 efficiently produced lactic acid (10.6 g/L), enabling the reduction of the wort's pH to 3.39. Sensory evaluation using the Temporal Dominance of Sensations (TDS) and Acceptance Test indicated that the indigenous yeasts produced beers with fruity and acidic sensory attributes, including acerola and lemon notes, in contrast to the malty, carbonated profile observed with the commercial S-04 strain. Both CCMA 0200 and CCMA 0233 yielded beers with alcohol content within the BJCP guidelines for Catharina Sour (4-5.5% v/v) and complex aromatic profiles, which are suitable for Catharina Sour production. Thus, beers produced with indigenous strains feature an interesting innovation rooted in Brazilian biodiversity. However, large-scale evaluations are still necessary for industrial use.