Characterisation of litchi juice fermented by probiotic lactic acid bacteria

In this research, production of probiotic litchi juice through its fermentation by three strains of lactic acid bacteria: Lactobacillus plantarum, L. Rhamnosus and L. acidophilus were examined. Fermentation was carried out at 37 °C for 72 h under microaerophilic conditions. Changes in pH, titrable acidity, sugar content, microbial population, color, total phenolic content and antioxidant were measured during the fermentation period and the viability of all strains was also monitored during storage at 4 °C for 4 weeks. The results indicate that L. plantarum and L. rhamnosus lowered the pH at the initial stages of fermentation along with greater sugar consumption than L. acidophilus and showed better microbial growth during fermentation. L. plantarum and L. Rhamnosus showed higher viability during the storage time. Viable cells remained at maximum level up to 2 weeks but decreased dramatically after 4 weeks. Total phenolic content and DPPH radical scavenging studies showed that fermentation of litchi juice using these strains of Lactobacillus increased the antioxidant activity with L. acidophilus exhibiting highest antioxidant capacity. The results indicated that litchi juice provides scope for use as a suitable medium for delivery of the probiotics on fermentation to enhance the health benefits of the juice.