Development of coffee kombucha containing Lactobacillus rhamnosus and Lactobacillus casei: Gastrointestinal simulations and DNA microbial analysis

Abstract

Kombucha is produced with a symbiotic culture of bacteria and yeast (SCOBY). Sugared coffee has potential as a fermentation substrate for kombucha production. Objectives of this study were to: (1) produce coffee kombucha (CK) with Lactobacillus rhamnosus (LG) and Lactobacillus casei (LC) and characterize its microbial diversity, (2) evaluate the physicochemical properties and determine viability of CK inoculums under simulated gastric and intestinal conditions during refrigerated storage. Coffee was fermented for 8 days at 23 °C. LG and LC were inoculated into CK (5% v/v) and stored for 15 days at 4 °C. Acetobacteraceae were predominant for the control and Lactobacillaceae for both treatments after 15 days. CK with LG or LC stored for 15 days had 7.44 and 8.77 log CFU/mL, respectively, after exposure to simulated gastric and intestinal conditions. The DNA sequencing analysis revealed that the addition of LG and LC to the CK shifted the proportion of microbial families from Acetobacteraceae to Lactobacillaceae. This study suggests that added Lactobacilli can subsist in CK for 15 days and survived simulated gastrointestinal transit.