Dados do Trabalho

Título

Selected biological activities of freeze-dried Bifidobacterium animalis paraprobiotic obtained by ohmic heating

Introdução

Paraprobiotics are known as inactivated form of probiotics, which have been reported to have several health-promoting benefits (HPBs) to their consumers. This study aimed to evaluate antimicrobial, glucosidase inhibitory, and angiotensin-converting enzyme (ACE) inhibitory activities of the paraprobiotic obtained from Bifidobacterium animalis Bb-12 (BB) through the ohmic heating (OH) process.

Material e Métodos

A bacterial suspension of BB (8 log CFU/mL) was treated by OH for 3 min. After ensuring the complete bacterial inactivation by evaluating the culturability, BB paraprobiotics (BBP) was freeze dried at 50 mTorr and –60˚C for 100 h, and the powder was then vacuum packaged and stored at 4˚C until the use. The serial dilution method was used in a 96-well microplate to determine minimum inhbitort concentration (MIC) of BB and BBP. To analyze α-glucosidase inhibitory activity, 50 μL of BBP (100 mg/mL) added to the same amounts of 4-nitrophenyl β-d-glucopyranoside and α-glucosidase (0.2 U/mL). After incubation of microplate at 37°C for 30 min, the absorbance was read at 405 nm. To analyze ACE inhibitory activity, a mixture of paraprobiotic (50 μL, 100 mg/mL), ACE enzymatic solution (50 μL, 10 mU/mL), and substrate solution (100 μL hypuryl-histidyl-leucine, 4.15 mmol/L) was incubated at 37°C for 30 min. After the preparation steps, the absorbance was read at 228 nm. In addition, a metabolomic analysis was performed using 1H NMR spectroscopy to identify the metabolites present in BB and its paraprobiotic.

Resultados e Discussão

BBP showed antimicrobial activity against Salmonella Enteritidis and Staphylococcus aureus, so that its MIC against them was measured 75 mg/mL, which was equal with the MIC of BB. The ACE-inhibitory activity of BB and BBP were measured 66.35 and 76.53%, respectively. As well as the glucosidase inhibitory activity of BB and BBP were measured 17.44 and 39.61%, respectively.

Conclusão

The significant increase in these activities could be attributed to the presence of higher concentrations of available metabolites in BBP compared to BB. Glycerol, ethanol, and lactate were measured respectively as the main metabolites in BB, while for BBP were respectively glycerol, acetate, and lactate. According to the results, BBP obtained by OH can be introduced as a health-promoting agent.