Yeasts from Canastra cheese production process: Isolation and evaluation of their potential for cheese whey fermentation

摘要

Canastra cheese is a cheese with geographical indication recognized by the Brazilian National Institute of IndustrialProtection under number IG201002. It is produced in seven municipalities in the state of Minas Gerais in aregion called Serra da Canastra. In thiswork, samples of milk, “pingo” (natural starter),whey and Canastra cheesewere collected on a farm inMedeiros-MG/Brazil to evaluate the yeast microbiota and select yeasts for whey fermentationto produce ethanol and volatile aromatic compounds of relevance in the production of cheese. Thirtynineisolates capable of fermenting lactose in a synthetic medium were identified by MALDI-TOF asKluyveromyces lactis (29), Torulaspora delbrueckii (7) and Candida intermedia (3). Eleven isolates of K. lactis andthree of T. delbrueckii efficiently fermented lactose until 4th day, and due to this reason were selected for cheesewhey fermentation with Brix 12, 14 and 18. Generally, the isolates T. delbrueckii B14, B35, and B20 and K. lactisB10 were the most effective regardless of the initial Brix value. The identification of these four isolates byMALDI TOF was confirmed by sequencing of the ITS region. In the fermentation of cheese whey 14 Brix, T.delbrueckii B14 and B35, respectively yielded 24.06 g/L and 16.45 g/L of ethanol, while K. lactis B10 was more efficientin the consumption of lactose. In sequential culture with K. lactis B10 inoculated 48 h after T. delbrueckiiB14, 97.82% of the total sugars were consumed resulting in the production of 19.81 g/L ethanol and 39 aromaticvolatile compounds. The most abundant compounds were 3-methyl-1-butanol, octanoic acid and ethyldecanoate, which are reported as important for the aroma and flavor of cheeses. Based in our results, B10 isolateinoculated 48 h after B14 isolate is a promising yeast inoculum to be used for fermentation of dairy substrates.