Enhancement of Spirulina platensis bioactivity by probiotic fermentation and encapsulation by spray-drying

The enhancing impact of fermentation with Lactiplantibacillus plantarum and drying/coating on bioactivity properties of Spirulina platensis was investigated. The fermentation with Lp. plantarum took place anaerobically for 72 h at 37 C. Encapsulation of fresh and fermented samples was made by spray-drying with a 170 degrees C air inlet temperature, a 20 mL/min feed flow rate and different ratios of coating material (1:0, 1:1 and 1:2 maltodextrin). Fresh Spirulina capsules exhibited different shapes, mostly rod form whilst fermented Spirulina exhibited a generally spherical shape. 1,1-diethoxy-ethane (34.02%) and tertbutyldimethylsilyl 2,2,3,3,3-pentafluoropropanoate (26.70%) were identified as the major compounds in fermented Spirulina. The total phenol content of Spirulina was in range from 14.22 mg gallic acid equivalent (GAE)/g for fermented wet spirulina to 77.27 mg GAE/g for fermented spray-dried Spirulina coated with maltodextrin at a ratio of 1:1. The drying and fermentation processes significantly increased the total phenol content, total antioxidant activity and diphenyl picrylhydrazyl (DPPH) radical scavenging capacity of Spirulina (P < 0.05). Bacteriostatic concentration of fermented spray-dried Spirulina was 25 mg/mL against Salmonella Paratyphi A, Staphylococcus aureus and Enterococcus faecalis, whereas bactericidal effect was at a concentration of 25 mg/mL vs. Pseudomonas aeruginosa and E. faecalis. The combination of fermentation with Lp. plantarum and drying after coating with maltodextrin of Spirulina enhanced its antimicrobial and antioxidant properties by 0.7-20-fold compared to fresh, wet Spirulina.

Automated summary

This study investigated the effects of fermentation and drying/coating on the bioactivity properties of Spirulina. The results showed that fermentation and drying/coating processes significantly enhanced the antioxidant and antimicrobial properties of Spirulina.