Layer-by-layer encapsulation of Lactobacillus delbrueckii subsp. Bulgaricus using block-copolymers of poly(acrylic acid) and pluronic for safe release in gastro-intestinal conditions. (August 2017)

• Record Type: Journal Article
• Authors: Quintana, G.; Simões, M.G.; Hugo, A.; Alves, P.; Ferreira, P.; Gerbino, E.; Simões, P.N.; Gómez-Zavaglia, A.
• Is Part Of: Journal of functional foods. Volume 35(2017)
• Page Start: 408
• Page End: 417
• Publication Date: 2017-08
• Subjects: [(CHI/PPP)1/0] Bacteria coated with a layer of chitosan and no layers of PPP -- [(CHI/PPP)1/1] Bacteria coated with a layer of chitosan and a layer of PPP -- [(CHI/PPP)2/1] Bacteria coated with two layers of chitosan and a layer of PPP -- [(CHI/PPP)2/2] Bacteria coated with two layers of chitosan and two layers of PPP -- 1H NMR Proton Nuclear Magnetic Resonance -- AA acrylic acid -- ATR-FTIR Attenuated total reflectance Fourier Transform Infrared Spectroscopy -- CFU colony forming units -- CHI chitosan -- DMEM Dulbecco's Modified Eagle's medium -- EO ethylene oxide -- FITC fluorescein isothiocyanate -- FITC-inulin fluorescein isothiocyanate bound to inulin -- GRAS Generally recognized as safe -- LbL layer-by-layer -- Mn number-average molecular weight -- MRS de Man, Rogosa, Sharpe medium -- MTT 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide -- NMR Nuclear Magnetic Resonance -- PAA poly(acrylic acid) -- PBS phosphate buffer saline -- PLU pluronic -- PO propylene oxide -- PPP polymer composed of PAA-PLU-PAA -- PPP12 PPP with molecular weight ∼12 kDa -- PPP24 PPP with molecular weight ∼24 kDa -- THF tetrahydrofuran; Layer-by-layer -- Lactic acid bacteria -- Pluronic -- Polyacrylic acid -- Bacterial safe delivery -- Storage; Functional foods -- Analysis -- Periodicals; Food -- Biotechnology -- Periodicals; Nutrition -- Periodicals; 613.2
• DOI: 10.1016/j.jff.2017.06.007
• Languages: English
• ISSNs: 1756-4646

Abstract

Highlights: Pluronic-acrylic acid block-copolymers were synthesized and characterized. L. bulgaricus CIDCA 333 was encapsulated with copolymers by layer-by-layer. Bacteria were plate counted after gastro-intestinal conditions simulation. Coating with 2/3 layers protected microorganisms from gastro-intestinal conditions. Coated bacteria were not toxic to eukaryotic cells and unchangeable during storage. Abstract: Lactobacillus delbrueckii subsp. bulgaricus CIDCA 333 was encapsulated by layer-by-layer (LbL) technique. Copolymers of pluronic and poly(acrylic acid), were synthesized and characterized, and chitosan was selected as cationic polyelectrolyte. The efficiency of encapsulation was evaluated by plate counting the microorganisms before and after coating, after freeze-drying with sucrose, and after exposure to simulated gastrointestinal conditions. Coated microorganisms with 2/3 layers were also protected against simulated gastro-intestinal conditions, while cultivability of uncoated bacteria significantly dropped. Confocal microscopy allowed determining the integrity and permeability of the coated and uncoated microorganisms. Coated bacteria were non-toxic to eukaryotic cells, by the MTT assay, and showed no significant decrease of cultivability before and after freeze-drying and after 60 days of storage at 4 °C. Considering the GRAS status of the used polymers, the results obtained revealed a potential delivery system of sensitive lactic acid bacteria strains in food products, ensuring their safe arrival to the gut.