Table 3 Microencapsulation of EOS bacteria using either pectin, κ-carrageenan, gellan gum or protein as a core scaffold matrix
EOS bacterial strain | Encapsulation technique (including cross-linker and critical oxygen exposure time) | Microcapsule Matrix Material | Purpose of employed anaerobic conditions | Bacterial Viability Following O₂ Exposure | Additional notes | Reference/study |
|---|---|---|---|---|---|---|
B. animalis BB-12 | Emulsification (0.8 M CaCl2; 30 min gel formation/hardening time) | Pectin | Bacteria culturing for encapsulation | High viability during storage (4 °C, 30 days) and under in vitro GI conditions (SGF: 2 h; SIF: 2.5 h) | HM Pectin PS was critical in protection (500–3000 nm); EE > 92% | |
B. bifidum R0071 | Emulsification (internal gelation) (0.05 M CaCl2; 1 h separation/hardening time) | Pectin | Bacteria culturing for encapsulation | High viability following in vitro GI conditions (SGF: 1 h; SIF: 1 h) | LM Pectin Pectin provided better protection than alginate | |
B. longum NCIMB 8809 | Extrusion (0.15 M CaCl2; 30 min hardening time) | Pectin | Bacteria culturing for encapsulation | High-to-poor viability during storage (4 °C, 4 weeks, in phenol- containing acidic pomegranate and cranberry juices), depending on the fruit juice environment | LM Pectin Coating with chitosan/gelatine/glucomannan improved storage stability Higher acid and phenol levels in fruit juices may further reduce storage stability PS = 2.7 mm | |
B. longum B6, B. longum ATCC 15708 | Emulsification (0.3 M KCl, no gel formation/hardening time reported) | Κ-carrageenan | CFU plating | High viability during storage (in yogurt, 4 °C, pH 4.6, 30 days) | PS = 22–350 μm | |
B. animalis subsp. lactis BB-12 | Emulsification (0.5 M CaCl2; 30 min gel formation/hardening time) | Κ-carrageenan (blended with alginate and glucose) | Bacteria culturing for encapsulation | Moderate viability during storage (4 °C and −18 °C, 30 days); Moderate viability in SGF (1.5 h) and SIF (1.5 h + 30 min pH adjustment)) | Provided better viability protection than alginate only microcapsules EE = 96.68– 98.85% | |
B. lactis | Extrusion (air knife technique) (0.1 M CaCl2; 1 h hardening time) | Gellan gum (blended with Xanthan gum) | Bacteria culturing for encapsulation | High viability during storage (in sodium-phosphate buffer, 4 and 22 °C, pH 6.8, 21 days) | Bacteria demonstrated a high degree of oxygen tolerance; PS = 20–2200 µm; EE = 10–12 log CFU/g | |
B. adolescentis 15703 T | Emulsification (0.12 mM genipin; 30 min stirring for emulsion formation and overnight gel formation) | Gelatine | Bacteria culturing prior encapsulation | Moderate viability in SGF (2 h) and sequential SGF (1 h), and SIF (4 h) | Viability was improved with alginate coating PS = 49.0– 53.1 µm; EE = 43.5% (most optimal) | |
B. bifidum F-35 | Emulsification (10 U transglutaminase per g of protein; 3 h stirring (emulsification/gelation) time) | WPI | Bacteria culturing prior encapsulation and CFU plating | High viability during storage (in yogurt, 4 °C, 14 days) | Storage stability was not significantly higher than unencapsulated bacteria; PS ~ 10 µm | |
B. animalis subsp. lactis Bb-12 | Emulsification (10 U transglutaminase per g protein; 180 min gelation time) | Sodium caseinate | CFU plating | High viability in SGF (90 min) | PS ~ 165 μm EE = 9.6 log CFU/g | |
B. animalis subsp. lactis Bb-12 | Emulsification (no cross-linker agent temperature-induced gelation; 180 min) | Skimmed milk concentrate | CFU plating | High viability in SGF (90 min) | PS ~ 68 μm (median) (d90,3 < 93 μm after pre-emulsification step) EE = 9 log CFU/g | |
B. bifidum | Extrusion (no cross-linker agent was used; 30 min self-gelation time) | WPI | Bacteria culturing prior encapsulation | High viability during storage (in yogurt, 4 °C, 28 days), and in SGF (4 h) and SIF (4 h) | PS = 1.53–1.90 µm EE = 95% |
