Microencapsulation of Lactobacillus plantarum in W/O emulsions of okara oil and block-copolymers of poly(acrylic acid) and pluronic using microfluidic devices

QUINTANA, GABRIEL; GERBINO, ESTEBAN; ALVES, PATRICIA; SIMÕES, PEDRO NUNO; RÚA, MARÍA LUISA; FUCIÑOS, CLARA; GOMEZ-ZAVAGLIA, ANDREA

FOOD RESEARCH INTERNATIONAL

ELSEVIER SCIENCE BV

Año: 2021 vol. 140

0963-9969

Okara oil is a by-product remaining from defatting okara, the solid residue generated after extracting the aqueousfraction of grounded soybeans in the elaboration of soy beverages. The goal of this work was to encapsulate theprobiotic Lactobacillus plantarum CIDCA 83114 into W/O emulsions composed of a block-copolymer constitutedof pluronic® and acrylic acid (PPP12) and okara oil, prepared in microfluidic devices. For comparative purposes,alginate was also included as a second dispersed phase. Lactobacillus plantarum CIDCA 83114 was suspended inPPP12 or alginate giving rise to dispersed phases with different compositions, named I, II, III and IV. Controlswere prepared by suspending microorganisms in water as dispersed phase. 6-carboxyfluorescein was added asbacterial marker in all the emulsions. The presence of green dyed bacteria in the dispersed phases, inside thedroplets of the emulsions and the absence of fluorescence outside them, confirmed the complete encapsulation ofbacteria in the dispersed phases. After being prepared, emulsions were freeze-dried. The exposure to gastricconditions did not lead to significant differences among the emulsions containing polymers. However, in all casesbacterial counts were significantly lower than those of the control. After exposing emulsions to the simulatedintestinal environment, bacterial counts in assays I, II and III (emulsions composed of only one dispersed phase orof two dispersed phases with bacteria resuspended in the PPP12 one) were significantly greater than those of thecontrol (p < 0.05) and no detectable microorganisms were observed for assay IV (emulsions composed of twodispersed phases with bacteria resuspended in the alginate one). In particular, bacterial cultivability in emulsionscorresponding to assay I (only PPP12 as dispersed phase) exposed to the intestinal environment was 8.22 ± 0.02log CFU/mL (2 log CFU higher than the values obtained after gastric digestion). These results support the role ofPPP12 as an adequate co-polymer to protect probiotics from the gastric environment, enabling their release inthe gut, with great potential for food or nutraceutical applications.