From Pollen to Bee Bread: A Reservoir of Functional Yeasts

Nowadays, yeasts are widely used for food and beverage fermentation as well as for their functional traits, as there has been an increase in scientific interest in their contributions to human health. Microbial competition in habitats with adverse abiotic factors could force yeasts to activate competitive tools, such as bioactive compound production. Here, bee pollen, fresh bee bread, and aged bee bread were analyzed as a reservoir of potential new functional yeasts. Microbiological analyses of pollen showed a dominance of bacteria and molds, although yeasts were present in all samples and increased in fresh and aged bee bread where osmophilic yeasts appeared. Functional traits such as antioxidant activity; polyphenol and flavonoid production; antimicrobial activity toward molds, yeast, and pathogenic bacteria; phytase activity; and potential probiotic aptitude were studied. Out of fifty-eight isolated yeasts, four showed antioxidant activity higher (around 70%) than Codex® due to having the highest levels of polyphenols or flavonoids. One strain possessed phytase activity, and three strains belonging to Starmerella and Metschnikowia genera had wide antimicrobial activity. Nine strains exhibited the ability to resist gastrointestinal conditions, and four possessed all probiotic traits tested. All these findings demonstrate the effectiveness of pollen and bee bread as natural sources for new bioactive and functional yeasts.