EFFECTS OF MICROENCAPSULATION OF CLA-PRODUCING LACTIC ACID BACTERIA.

GONZÁLEZ, I.; ROSS, R.; VAN NIEUWENHOVE, C.;; GONZÁLEZ, S.

S.M. de Tucumán

Simposio; IV Simposio Internacional de Bacterias Lácticas-; 2013

CERELA-CONICET

Conjugated linoleic acid (CLA) is a mixture of positional and geometric isomers of linoleic acid (LA) with conjugated double bonds. It is produced during the hydrogenation of dietary LA in rumen, being dairy foods and ruminant meats the main natural sources of CLA. It has received great attention for their beneficial health properties such as cancer and atherosclerosis prevention, immunomodulation, and body fat reduction. Natural CLA production is far below physiological effective level; so it is necessary to obtain CLA enriched food. Certain strains of lactic acid bacteria (LAB) are able to conjugated LA in vivo. Therefore, microencapsulation is an excellent alternative to protect bacteria through gastrointestinal tract. The aim of this work was to encapsulate CLA-producing LAB, evaluating viability in simulated gastrointestinal (SGI) conditions and CLA-production after encapsulation process. CLA-producing LAB (Lactobacillus plantarum CRL353, Lactobacillus plantarum CRL355 and Lactobacillus acidophilus CRL44) were encapsulated by ionic gelation method using: 1% (w/v) sodium alginate sterile solution, LAB suspension (109 CFU/mL) in 20% (w/v) non fat milk and 0.1M calcium chloride (hardening solution). Non fat milk (20%, w/v) bacteria suspension (109 CFU/mL) was used as Control. To evaluate SGI resistance, LAB alginate beads obtained were resuspended sequentially in gastric (NaCl 2 g/L, pepsin 3.2 g/L, and HCl 7 mL; pH 1.2) and intestinal solutions (KH2PO4 6.8 g/L, 0.2N NaOH 250 mL, and pancreatin 10 g/L; pH 7.2). At different time intervals, samples were withdrawn from the SGI medium. Viable cell counts were determinated by spreading on MRS agar and incubation at 37??C for 48 h. CLA-bioproduction was evaluated before and after encapsulation process. Capsules and Control suspension were inoculated in MRS broth containing LA (60 ?Êg/mL) as substrate, and were anaerobically incubated at 37??C for 24 h. Lipids were extracted using chloroform/methanol (2:1, v/v) solution, they were saponificated with 0.9% (w/v) methanolic NaOH, derivatized to methyl esters and finally injected in a gas chromatograph equipped with flame ionization detector and a HP-88 capillary column (100 m ?~ 0.32 mm interior diameter ?~ 0.25 ?Êm of thickness). Fatty acids were identified by comparison with the retention times of methylated standards. Results were expressed as ?Êg/mL of culture.