Influence of fermentation by lactic acid bacteria and in vitro digestion on the biotransformations of blueberry juice phenolics

Enzymes secreted during fermentation by lactic acid bacteria (LAB) may induce structural changes, e.g., promote the transformation of polyphenols in fruits and vegetables and thus influence their bioavailability and antioxidant capacity. This study describes the effects of fermentation by different LAB types (Streptococcus lactis and Pediococcus pentosaceus) and simulated gastrointestinal digestion on the biotransformation and antioxidant capacity of blueberry phenolics, revealing that upon the digestion of fermented samples, antioxidant capacity increases with increasing biotransformation extent because of the concomitant formation of more potent antioxidants. Moreover, the fermentation of blueberry puree increases the bioavailability and bioacceptability of phenolics and thus promotes the survival of LAB after digestion. The best results are obtained for S. lactis, and this LAB type is therefore concluded to hold great promise for the food industry. •Effects of fermentation and simulated digestion on blueberry phenolics were probed•Two lactic acid bacteria were used, Streptococcus lactis and Pediococcus pentosaceus•The biotransformations and antioxidant capacities of phenolics were investigated•Fermentation benefitted both bioavailability and antioxidant activity•S. lactis was the most suitable LAB type for blueberry fermentation