Survival of commercial probiotic strains in dark chocolate with high cocoa and phenols content during the storage and in a static in vitro digestion model

Abstract

The effect of phenols on the microbial growth is still debated, as they could act as antimicrobials or as protective agents. In this study, we evaluated the survival of different lyophilised probiotic strains in dark chocolate with 80% cocoa and high total phenols content. Our results showed that the survivability of probiotics in dark chocolate stored at 18 °C for 90 d is a strain-dependent character and is strongly influenced by the inoculum mode, whereas phenols did not seem to influence the survival. In particular, the pre-suspension of probiotics in UHT milk before the addition to dark chocolate caused a great loss of survival during the storage, even if metabolic activities of possibly reactivated cells were not observed. The probiotic chocolates were characterised, for the entire storage period, by an excellent sensory quality. Moreover, the dark chocolate offered a good protection to probiotics during the simulated gastrointestinal transit.

Keywords

• Dark chocolate
• Probiotic
• Viability
• Gastro-intestinal survival
• Phenols