Effects of microencapsulation of CLA-producing lactic acid bacteria

GONZÁLEZ, IVANNA; ROMINA ROSS; CARINA VAN NIEUWENHOVE; GONZÁLEZ, SILVIA.

Simposio; IV International Symposium on Lactic Acid Bacteria: Food, Health and Applications; 2013

MICROENCAPSULATION OF CLA-PRODUCING LACTIC ACID BACTERIA. EVALUATION OF CLA-BIOPRODUCTION. I. González1, G.R. Ross1, C.P. Van Nieuwenhove 2 1 Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán. Ayacucho 491 ? 4000 ? Tucumán, Argentina. E-mail: romiross23@yahoo.com.ar 2 Centro de Referencia para Lactobacilos CERELA-CONICET. Chacabuco 145 ? 4000 ? Tucumán, Argentina. Conjugated linoleic acid (CLA) is a mixture of positional and geometric isomers of linoleic acid (LA) with conjugated double bonds. It is produce 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 physiologically 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 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 CRL 353, Lactobacillus plantarum CRL 355 and Lactobacillus acidophilus CRL 44) were encapsulated by ionic gelation method using: 1.8% (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 At different time intervals, samples were withdrawn from the SGI medium.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 determinate 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 μg/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 μm of thickness). Fatty acids were identified by comparison with the retention times of methylated standards. Results were expressed as μg/mL of culture. Results show that encapsulation increased significantly viability of Lactobacillus plantarum CRL 353, Lactobacillus plantarum CRL 355 and Lactobacillus acidophilus CRL 44 under SGI conditions than Control. Also it was demonstrated that LA conjugation capacity of these strains was not affected by this process. Therefore, encapsulation could be a useful and efficient way to vehicle microorganisms widely in functional foods.