Dados do Trabalho

Título

COMPARISON OF THE STABILITY OF FREE AND ENCAPSULATED BLIS INCORPORATED INTO A BIOPOLYMERIC MEMBRANE, RELEASED IN A SIMULATED FOOD MATRIX

Introdução

Biopreservation has proven to be a potential alternative for food safety. Bacteriocin-type inhibitors (BLIS) are natural compounds of protein origin with very pronounced antimicrobial activity, but which can be inactivated in foods with a high protein and lipid content. Encapsulation techniques can be used to improve their stability and bioavailability. The objective of this work was to develop a biopolymeric membrane added with BLIS in free form and liposome-encapsulated, to evaluate the release in a simulating fluid.

Material e Métodos

The L. sakei strain was grown in Man, Rogosa, and Sharpe (MRS) medium without shaking at 32.5 °C for 96 h. After centrifugation, the supernatant containing BLIS was encapsulated in liposomes by the thin-layer hydration method. It was evaluated the influence of three fat-free soybean lecithin types with a minimum content of 45, 70 and 95% (mm-¹) phosphatidylcholine and 6.39, 8.68 and 11.93 mg.mL-¹ protein as hydration solution, respectively, using the one-factor-at-a-time (OFAT) approach. The liposomes with the best stability and antibacterial activity were added to a biopolymeric membrane of agar and chitosan, produced using total polymer ratio of 1:100 (m/v). The membrane was in contact with the fatty food simulant solution by RDC resolution Nº 51 of 2010 for 4 h at 100 °C. The release of BLIS was evaluated by antibacterial analysis of the simulant solution using the microdilution technique.

Resultados e Discussão

The liposomes obtained using lecithin with 45% phosphatidylcholine showed the greatest colloidal stability, which was confirmed by the ζ-potential of -33.98 mV, the polydispersity index of 0.33 and the hydrodynamic diameter of 3.54 µm. The protein concentration of 8.68 mg.ml-1 and 45% (mm-¹) phosphatidylcholine content resulted in a liposome with antibacterial activity of 100% inhibition of Escherichia coli and Staphylococcus aureus. The liposome-incorporated membrane showed a release of BLIS capable of inhibiting 86.93% of S. aureus, while the blend added with free BLIS showed a release capable of inhibiting 46.58% of the same bacterium in the simulating fluid.

Conclusão

This suggests an increase in the stability of encapsulated BLIS, highlighting the potential for investigating stability in situ.