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

Abstract

SummaryThe 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 °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 tert‐butyldimethylsilyl 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.