Combination of probiotic yeast and lactic acid bacteria as starter culture to produce maize-based beverages

Cereal-based fermented beverages are non-dairy products which are considered possible carriers for probiotic strains and alternatives for use by vegans and lactose-intolerant consumers. In the present work, the commercial probiotic, Lactobacillus paracasei LBC-81, was used singly and in co-culture with potential probiotic yeasts, Saccharomyces cerevisiae CCMA 0731, S. cerevisiae CCMA 0732, and Pichia kluyveri CCMA 0615, to ferment a maize-based substrate. All tested strains showed viability higher than 6 log CFU/mL, as recommended for food probiotic products, except for the yeast P. kluyveri which decreased during fermentation and storage time. A reduction in pH value, from approximately 7 to 4, was observed. This decrease was due organic acid production, which did not affect the microbial viability. Lactic and acetic acids were the main organic acids produced during fermentation, and they decreased over 28 days of storage (<0.5 and 0.1 g/L for lactic and acetic acids, respectively). Ethanol was detected in the S. cerevisiae assays; however, the content was <5 g/L in a non-alcoholic beverage. Seventy volatile compounds were detected, including acids, alcohols, aldehydes, esters, ketones, and other compounds. Sensory analysis showed score of 5.93-4.57, respectively for appearance and taste. This is an important result, considering that the beverage had no flavoring additive and lacked a sweet taste. Therefore, probiotic beverages were successfully obtained by maize fermentation inoculated with co-culture of S. cerevisiae (CCMA 0731 or CCMA 0732) and L. paracasei LBC-81.