Scale up of layer-by-layer microencapsulation of probiotic lactic acid bacteria

GINA TAVARES; NELSON ROMANO; STEPHANIE PASSOT; GUERRERO-SÁNCHEZ, MARÍA; SONIA CAMPOY; MARINA GOLOWCZYC; FERNANDA FONSECA; PEDRO SIMOES; ANDREA GÓMEZ-ZAVAGLIA

Nantes

Congreso; ICEF 14 INTERNATIONAL CONGRESS ON ENGINEERING AND FOOD; 2023

Société Française de Génie des Procédés

This study aims to optimize the scale up oflayer-by-layer microencapsulation of Lactiplantibacillus plantarumWCFS1. Chitosan and alginate were used as cationic and anionicpolyelectrolytes, respectively. Processing parameters like biomass production,number of polymers layers and biomass/polymers ratio during the encapsulationwere evaluated. The efficiency of encapsulation was assessed by plate countingthe microorganisms before and after coating, after spray-drying withfructo-oligosaccharides (FOS) and maltodextrin as protective matrix, and afterexposure to simulated gastrointestinal conditions. Bacteria cultured at constantpH and harvested at the early stationary phase showed lower decrease ofcultivability (0.5 to 1 Log CFU/mL) than those produced under non controlledconditions (overnight culture without pH control, 4 Log CFU/mL decrease). Theaddition of up to two coating layers (first layer of chitosan and second layerof alginate) did not significantly affect bacterial cultivability, which wasnegatively affected by the incorporation of additional layers. The coatingprocess was monitored by ζ-potential measurements to determine the optimalratio of polymers-to-biomass. Results showed that bacteria coated only withchitosan or by chitosan/alginate, exhibited constant ζ-potential up to 1:10polymers:biomass ratio (p>0.05). The encapsulation capacity of chitosan andalginate was insufficient at a higher ratio (1:25) as suggested by noticeablechanges of ζ-potentials. Spray-drying induced a decrease of cultivability of 0.8 and0.4 Log CFU/mL in control uncoated bacteria and layer-by-layer coated bacteria,respectively. After rehydration, coated bacteria withchitosan and alginate were protected against simulated gastrointestinalconditions, while the cultivability of control uncoated bacteria droppedsignificantly. The results obtained support the feasibility of scaling-up thelayer-by-layer encapsulation process for the delivery of sensitive lactic acidbacteria strains while ensuring their safe arrival to the gut.